Any recommendations for my honda bf20. Original prop is 4 blade 9-1/4x10 I change to prop 3 blade 9-1/4x9 one down lower pitch but my rpm is still 4500. Do i need more lower my pitch?
You're sure your tachometer is reading accurately or is set to the correct pulse/pole setting? What kind of boat is it on? That motor should be able to run up to 5500 to 6000 usually, so in theory you'd want less pitch, but you may not have much lower options to drop to. You could also try raising the motor on the transom to help reduce drag. If it's on a pontoon boat and you can't get the RPMs up I would just recommend avoiding using the higher throttle ranges unless absolutely necessary. That should at least help prevent doing harm to the motor. Slow putting around with the wrong prop isn't going to do as much harm as trying to run the motor hard with it.
any recommendations for a Honda bf50d with a range of 5500-6000, im running a SOLAS Amita 12-2/5 x 8 RH 3311-122-08 prop with a max rpm of 3400-3600..... the propeller house i got it from said this was good and they wouldn't change it.. but i didn't think that was right and after watching this i know its not..
What kind of boat is it on? Pontoon? I would be concerned that your tach might not be reading properly. 8" pitch is very low and would usually have RPMs quite high. For instance, we usually run an 11" pitch on the 60 hp Mercurys that we install and that puts those motors in the sweet spot of around 5700 RPM.
@@tomspontoons all appearances it seems to work properly, idle is correct and it comes up smooth and consistent. it doesn't sound like it is running in the upper rpm range but i will find a way to check that. it is a 23ft pontoon. not sure how to verify the gauge is working correctly but i will do some investigating. Thanks!
@@stockenterprises9391 The only way I really know how to check is to hook in another gauge to the tach sending wire that is new and should be operating correctly. Otherwise you can check the pole/pulse setting on the back of the tach (if it's not a Honda brand gauge). It may need to be changed. They can seem to read accurately to a point in the RPMs and then miss, or they can be way off. I've seen both.
The owners manual will tell you what your operating range of RPMs should be at wide open throttle, but will not give you any guidance to prop diameter and pitch. That will have to come through testing with a tachometer.
What should an old school Johnson 15 HP run at at wot? Just installed a tach and I’m sure i can get a little more out of it. Seems to be low on rpm. From my understanding it should be in the 6000-6500 range.
I refer to this chart for all of my WOT numbers: www.kirschbaum.at/ki_prop/pdf/2015/RPM%20Chart.pdf It looks like you're correct, according to the chart an older 1980s vintage Johnson/Evinrude 2 cycle should run somewhere between 5500 and 6500 RPM.
Good, glad you found my channel. I have a few gauge install videos for different brands. I primarily use Faria Gauges as I've found them to be the most universal and user-friendly with outboards. Check out my playlists for electrical stuff and engine rigging.
You'll get cavitation or ventilation from two things typically...the motor being mounted too high on the transom OR a disturbance of water flowing to the propeller. The first has an obvious fix...lower the motor until the cavitation stops. The second is a little trickier because every boat is different. In my observance, some pontoons just weren't designed with high HP motors installed. So if they ran ok out of the factory with a 25hp or 40hp then they kept making them that way. When higher speeds are reached with higher hp the flow of water changes and can cause issues with how it feeds the motor. Again, lowering the motor would be the first way to fix it. Other things that can help with it are hydrofoils (aka whale tale) on the motor to help smooth the flow of water feeding the prop. Also, moving the entire transom back can help as well. The flow of water off the pontoons (standard pontoon, not tritoon) is very interesting to watch at higher speeds. The water will sort of flow down off of the pontoons just forward of the backs of the toons...if the motor is tucked up in front of the outer toons that flow down will make the better flow of water go "under" the prop. Water will always rise back up after being displaced by a hull, so moving the motor back a couple feet can help with that. Lots of variables here, but usually step one is lower the motor if that's possible!
@@tomspontoons i forgot too add that I'm not able to trim the motor up at all it will just cavitation /ventilation thanks again for your help hope you all have a great weekend!!!
@@ronaldsmith4068 That's a tricky one! Lowering the motor should eventually take care of the issue. I would probably lean towards that instead of moving the transom back, unless you're tearing the boat down to restore at the same time. Crest doesn't allow for access to the transom bolts from the underside...Their crossmembers only give access when the deck is removed.
I have a 16ft alumacraft with a 90 hp Yamaha. At 4500 rpm it porpoises. I've changed props and it still porpoises . I have tried a 17 and 15 inch props. 15 inch I get less porpoise but still there. Rpm went up, of course with the 15 pitch. I'm running at 5000 rpm and have lots of throttle left
Your porpoising (bouncing of the bow) has more to do with needing more weight up front OR more negative trim (or both). Make sure your motor’s trim is adjusted to be able to go all the way down so that you’re getting as much negative trim as possible to help get the bow down. Sometimes there’s a bolt or a pull pin that allows more negative trim. Worst case you can install negative wedges between the motor and boat that will give more negative trim.
A 4 blade prop will tend to lift the stern somewhat, thus may help. Try to borrow one for testing. It's very important your engine can operate to it's maximum rpm, thus a known calibrated tachometer should be used. One big cause of porposing is a hull with too much rocker shape, weight in the front to bring the bow down will probably help as well.
Thanks for this video! We purchased a new to us 2006 Sun Tracker Fishing Barge 21 with a Mercury 90ELP T 4-stroke. The boat came with a Solas 14" 11 pitch prop which doesn't seem right. We took it out the other day and got to 5500 RPM way before WOT. We got to 18mph at that RPM. I didn't want to push it any more past that as far as the RPM goes. We also got what seems to be cavitation?...not sure what that really is, but my husband says that's what it is! LOL. It performed well at 3500 RPM but only doing about 10mph...going nowhere fast! Any tips or suggestions? Thanks!
That does seem like a low pitch for that motor and boat combination. That motor should run up to around 5,800 to 6,000 RPM at wide open throttle with a light load. I would expect to see 25 mph out of that boat. I'd start by going up to a 13" pitch which should drop the RPMs a little bit and might give you better bite. Your 11" might be so flat of a pitch that it's having slipping issues. Really hard to say without being there to see and hear everything happening, but I'd start by going up in pitch a couple inches to where you can really test wide open throttle without going over 6,000 RPM.
I have a Merry Fisher 605 with a 2021 Merc 60CT(Bigfoot) with a Aluminum 3 Blade Blackmax 13x21P Prop. Its hard to bring the Boat on Plane. WOT 5600rpm. Someone told me switch to a 4 Blade. Would you change also the Pitch. I dont care about highSpeed i yust want quick Plane. Would you go with higher Pitch on a 4 Blade ?
Those look like fairly heavy boats for a 21P prop on a 60CT. I think a 4 blade would help, but I would also drop down to at least a 19" pitch, maybe even a 17" to get those RPMs up to 6000 at WOT with an empty boat. I think it needs the lower pitch more so than a four blade personally. Even if the boat can push 6000 RPM with a couple people it's not a bad thing, and it will get you on plane way faster. That's what I'd do!
Outstanding information Tom, and caputation queen. It's almost shameful the expense of a stainless prop and the added potential damage they can cause. Questions: How much of performance loss can I expect from prop damage like not smooth blades? Are 4 blade props best for top end performance? Does 3 or 4 blade props do the best reverse handling. There used to be a local prop shop near me for decades, which is nla. When should a prop be restored? What are things to look for besides decreased performance? I try to keep an extra prop and hardware onboard bc you never know right. I saved the day of fellow boaters having extra sheer pins, plugs, and hose.
Great questions! It seems to be that a little chewing on the ends of the props doesn't change things terribly, but then a little more damage and you may start to see some speed loss, slippage, and abnormal vibration. On a pontoon boat the speed loss may not be noticeable until there's significant damage compared to a planing style hull. I find that three blade stainless props will yield best top speed. They allow for larger diameters and each blade can have a bit more cup to them. Obviously, there will be others out there who swear by four blade...so I'm thinking this is a "to each their own" scenario, and different hull/motor combos might react differently too. Four blade props should do best for grabbing water at the dock for fine tune handling, reversing, etc. If there's anything more significant than what I can touch up with a hand file then I would say it's time to have it restored. Things can get out of balance if you try to fix majorly damaged blades. I think the biggest signal that it's time to have it restored or replaced is when you're feeling the abnormal vibrations or shaking at certain (or all) RPMs. When I knocked most of a blade off on the river a couple years ago the boat would run slower but ok at certain RPMs. A little higher or a little lower than that sweet spot and it felt like the whole boat was going to shake apart! We got home ok, but had to swap that prop out right away!
Im only getting about 5000 to 5200 out of my 90hp Mercury in my 17 foot flats boat at 30 mph at full throttle when i put the trim tabs up the boat starts to porpois but i pick up speed. im running 19p prop should i go down to 17p?
Yes, I would drop down in pitch to get those RPMs up, assuming it's a four stroke. You may need to check where your tilt pin is at in the lowest position. Sometimes there's a pull pin or bolts that limit the amount of negative trim the motor can get. Porpoising is usually from not enough negative trim or not enough weight in the bow. You might need to keep those trim tabs down just a bit to limit the porpoising. Either way, I'd want to get those RPMs back up in the operating range which should level out all around performance with whole shot and top speed.
No, it really should not have any impact as there is little to no resistance to the motor/boat from the air. It's the load from the motor pushing the boat through water with a load that impacts the RPMs the most.
I would run it through the same steps discussed in the video running it wide open throttle paying attention to the tachometer and where the RPMs are in relation to the recommended range for that motor. You can go check out Mercury's Prop Selector to get a start too.
Hey Tom, I’m new to owning a boat and looking for advice on my new to me(used ) pontoon. I just watched your video and I’ve learned a little from it but looking for more clarification. I have a 21ft pontoon with a 75 hp merc 2 stroke. I’m only able to run at best 17 mph at 5000 rrpms. I’m also having a problem with the pontoon plowing through the water and unable to plane on top of the water. Currently running a 15 pitch prop and was advised to possibly look at changing it as well as getting a hydrofoil Any advice? Thanks
Looks like a 75 hp (1990-2005 years, non optimax) should run 5250 at wide open throttle with an empty boat. You could look to drop to a 13 inch pitch, but might have to watch your RPMs if you’re alone at wide open…however it’ll probably help a lot with when there’s a load of people and it might help with torque to get the bow up a little when trimmed up. A hydrofoil would help too, but not a fix for every boat. It’s a lot of boat to move for a 75 hp so I’m not sure you’ll see a big speed change or improvement either way.
@@tomspontoons thanks for the feedback. Loaded or unloaded (people or gear) it will only hit 5000 rpms. I put a hydrofoil on today and ran it, no improvement. I still can’t get the front end up on the water. I’m assuming the front furniture is too heavy for it. I was hoping to overcome that by the help of a hf and a new prop. I can’t afford to build the motor or buy a bigger one for now so I will try a prop next. So my question now is if I’m trying to gain top end speed do I go to a higher pitch or lower, to the 13 ?
@@MrCornbread1980 I think you’re pretty much seeing your max speed. Lowering in pitch would get your RPMs up slightly, but I don’t see that making any changes to top end speed. There’s a point with every pontoon boat or other non-planing hull where the motor just can’t move enough water to make the boat go faster, despite RPM changes. The boat just doesn’t lift enough compared to a planing hull like a fishing boat or speed boat.
Hello Tom I have a 24’ pontoon boat with a 75 Yamaha at WOT tac 3500 rpm 21mph the prop is a 125/8x21-k could you give me bast way to to up the rpm mph ?? Thanks Bill
Is it a two or four stroke? Assuming your tach is accurate that's way low for either 2 or 4 stroke motor. You'll want to drop in pitch...remember that each inch you drop in pitch is going to add about 200 rpm to your WOT. Also, make sure you're testing those numbers with an empty boat...not a boat full of people and gear!
@@mrbowfam dropping 4” would get you to the 4300 rpm range. If it’s a two stroke I’d still want to see it higher. You might end up all the way down at a 15” or even 13” depending what motor you’re running and the specs for WOT operating range. Super common for pontoons to run those lower pitch props!
@@mrbowfam That's not a super common motor around where I'm from! It looks like it should run anywhere from 4500 to 5500 WOT range from what I found online. The diameter will likely change a little, but I wouldn't be concerned about the diameter. I would probably drop right down to the 13" if it were my boat to try to get those RPMs up in the healthier range!! Not sure you'll see a speed change, but all around torque and control will improve, plus it'll be better for the engine to get the proper high RPMs.
Evinrude props are often labeled on the backside where the exhaust comes out. It may be covered by a nut and washer or just dirty from exhaust. Did you check there? Otherwise you’d need to have a prop shop take a look and they should be able to tell you. If it were my boat, that size with that HP motor I would probably run a 10” or 11” pitch.
Need help !! I will get a new pair of Suzukis DF 150 APX for a boat AS MARINE 26 GL. I need a set up for speed weight is 5700 pound wet with fuel , water etc. What kind of props du you recommend? Thank`s for help
Oh man, that’s far beyond my scope of rigging!!! I would call the boat manufacturer first to see what they recommend, then the dealer to see what’s worked on the other boats they’ve rigged similarly. Then search the outboard manufacturers websites for the testing they’ve done with different boats and motors. From that research you should be able to come up with the information you need to make the smartest purchase possible!! Sorry I can’t be of more specific help on this one!
@@tomspontoons Thanks for your answer, but the manufacturer doesn´t test the twinn rigging. But thanks, It seems I have to get the long way and check by myself dif. setups.
@@7markshark that’s wild that they don’t offer some info. I’d also check with other boat manufacturers of similar hulls and motor setups before making the purchase of two stainless props!!
I’m hoping you can help me. I’ve made tons of phone calls. My tack doesn’t work. I have a 1993 four winns horizon 190 with a 5.0L Volvo penta with a OMC cobra standard outboard (not the xs) I have no idea what my RPMs are. The prop on the boat when I purchased was a 15x17 hole shot is good pulls tubes nicely, but my top speed is only about 30-35 mph according to what I did find I should be able to reach 46-50mph. I would love to have a good holeshot. Still pull tubes but I really want to increase my top end speed. Again I don’t know what my RPMs are. Please help
Best bet is to wire in a new tachometer to see if your tach is just bad. Only a few wires to switch over to the new tach. Without knowing RPMs there’s not much else that you can do. Sounds like you’re probably running a little low of pitch if you have good wholeshot but slow top end. Worst case, might have to have a repair shop take care of it.
literally the best video out of the 12 videos that I saw before this one, thank you.
Awesome! Thank you for watching and leaving a comment. I’m out here to teach as much as possible when it comes to boating!
That was a really really great breakdown! Thanks Tom
Thanks for watching, I'm happy to help!
Excellent explanation could not be any better perfect
Thank you so much for the kind words!!
Thanks for the well rounded and full explanation of props. Much appreciated
That’s what I was going for, glad it helped!
Thanks Tom very interesting
Cheers from Aus
Thanks for watching!
Any recommendations for my honda bf20. Original prop is 4 blade 9-1/4x10
I change to prop 3 blade 9-1/4x9 one down lower pitch but my rpm is still 4500.
Do i need more lower my pitch?
You're sure your tachometer is reading accurately or is set to the correct pulse/pole setting? What kind of boat is it on?
That motor should be able to run up to 5500 to 6000 usually, so in theory you'd want less pitch, but you may not have much lower options to drop to. You could also try raising the motor on the transom to help reduce drag. If it's on a pontoon boat and you can't get the RPMs up I would just recommend avoiding using the higher throttle ranges unless absolutely necessary. That should at least help prevent doing harm to the motor. Slow putting around with the wrong prop isn't going to do as much harm as trying to run the motor hard with it.
Cori brings up a great point!!!!
She’s got lots of great points…especially regarding cavitation.
That’s some good intel Tom.
Thanks! Hoping it'll help some folks get their boat dialed in.
any recommendations for a Honda bf50d with a range of 5500-6000, im running a SOLAS Amita 12-2/5 x 8 RH 3311-122-08 prop with a max rpm of 3400-3600..... the propeller house i got it from said this was good and they wouldn't change it.. but i didn't think that was right and after watching this i know its not..
What kind of boat is it on? Pontoon? I would be concerned that your tach might not be reading properly. 8" pitch is very low and would usually have RPMs quite high. For instance, we usually run an 11" pitch on the 60 hp Mercurys that we install and that puts those motors in the sweet spot of around 5700 RPM.
@@tomspontoons all appearances it seems to work properly, idle is correct and it comes up smooth and consistent. it doesn't sound like it is running in the upper rpm range but i will find a way to check that. it is a 23ft pontoon. not sure how to verify the gauge is working correctly but i will do some investigating. Thanks!
@@stockenterprises9391 The only way I really know how to check is to hook in another gauge to the tach sending wire that is new and should be operating correctly. Otherwise you can check the pole/pulse setting on the back of the tach (if it's not a Honda brand gauge). It may need to be changed. They can seem to read accurately to a point in the RPMs and then miss, or they can be way off. I've seen both.
would the one in an owners manuel detemine all
this
The owners manual will tell you what your operating range of RPMs should be at wide open throttle, but will not give you any guidance to prop diameter and pitch. That will have to come through testing with a tachometer.
What should an old school Johnson 15 HP run at at wot? Just installed a tach and I’m sure i can get a little more out of it. Seems to be low on rpm. From my understanding it should be in the 6000-6500 range.
I refer to this chart for all of my WOT numbers:
www.kirschbaum.at/ki_prop/pdf/2015/RPM%20Chart.pdf
It looks like you're correct, according to the chart an older 1980s vintage Johnson/Evinrude 2 cycle should run somewhere between 5500 and 6500 RPM.
Thank you for the reply. I appreciate it.
@@doctordifferentialspeedsho9506happy to help!
Just looking at getting a new prop, Very Helpful, and timely. Question; do you have gage recommendations videos ?
Good, glad you found my channel. I have a few gauge install videos for different brands. I primarily use Faria Gauges as I've found them to be the most universal and user-friendly with outboards. Check out my playlists for electrical stuff and engine rigging.
hello thanks for the awesome video can you give me some info on cavitation /ventilation issues. i have a crest 24 foot with 120 hp evenrude tia
You'll get cavitation or ventilation from two things typically...the motor being mounted too high on the transom OR a disturbance of water flowing to the propeller. The first has an obvious fix...lower the motor until the cavitation stops. The second is a little trickier because every boat is different. In my observance, some pontoons just weren't designed with high HP motors installed. So if they ran ok out of the factory with a 25hp or 40hp then they kept making them that way. When higher speeds are reached with higher hp the flow of water changes and can cause issues with how it feeds the motor. Again, lowering the motor would be the first way to fix it. Other things that can help with it are hydrofoils (aka whale tale) on the motor to help smooth the flow of water feeding the prop. Also, moving the entire transom back can help as well. The flow of water off the pontoons (standard pontoon, not tritoon) is very interesting to watch at higher speeds. The water will sort of flow down off of the pontoons just forward of the backs of the toons...if the motor is tucked up in front of the outer toons that flow down will make the better flow of water go "under" the prop. Water will always rise back up after being displaced by a hull, so moving the motor back a couple feet can help with that.
Lots of variables here, but usually step one is lower the motor if that's possible!
thank you so much my motor is all the way down would you cut the transom down or move it back thanks again @@tomspontoons
@@tomspontoons i forgot too add that I'm not able to trim the motor up at all it will just cavitation /ventilation thanks again for your help hope you all have a great weekend!!!
@@ronaldsmith4068 That's a tricky one! Lowering the motor should eventually take care of the issue. I would probably lean towards that instead of moving the transom back, unless you're tearing the boat down to restore at the same time. Crest doesn't allow for access to the transom bolts from the underside...Their crossmembers only give access when the deck is removed.
@@tomspontoons thanks again I really appreciate it
I have a 16ft alumacraft with a 90 hp Yamaha. At 4500 rpm it porpoises. I've changed props and it still porpoises . I have tried a 17 and 15 inch props. 15 inch I get less porpoise but still there. Rpm went up, of course with the 15 pitch. I'm running at 5000 rpm and have lots of throttle left
Your porpoising (bouncing of the bow) has more to do with needing more weight up front OR more negative trim (or both). Make sure your motor’s trim is adjusted to be able to go all the way down so that you’re getting as much negative trim as possible to help get the bow down. Sometimes there’s a bolt or a pull pin that allows more negative trim. Worst case you can install negative wedges between the motor and boat that will give more negative trim.
I have the same set up with a 10 1/2 inch 14 pitch prop and it does good.
A 4 blade prop will tend to lift the stern somewhat, thus may help. Try to borrow one for testing.
It's very important your engine can operate to it's maximum rpm, thus a known calibrated tachometer should be used.
One big cause of porposing is a hull with too much rocker shape, weight in the front to bring the bow down will probably help as well.
Thanks for this video! We purchased a new to us 2006 Sun Tracker Fishing Barge 21 with a Mercury 90ELP T 4-stroke. The boat came with a Solas 14" 11 pitch prop which doesn't seem right. We took it out the other day and got to 5500 RPM way before WOT. We got to 18mph at that RPM. I didn't want to push it any more past that as far as the RPM goes. We also got what seems to be cavitation?...not sure what that really is, but my husband says that's what it is! LOL. It performed well at 3500 RPM but only doing about 10mph...going nowhere fast! Any tips or suggestions? Thanks!
That does seem like a low pitch for that motor and boat combination. That motor should run up to around 5,800 to 6,000 RPM at wide open throttle with a light load. I would expect to see 25 mph out of that boat. I'd start by going up to a 13" pitch which should drop the RPMs a little bit and might give you better bite. Your 11" might be so flat of a pitch that it's having slipping issues. Really hard to say without being there to see and hear everything happening, but I'd start by going up in pitch a couple inches to where you can really test wide open throttle without going over 6,000 RPM.
I have a Merry Fisher 605 with a 2021 Merc 60CT(Bigfoot) with a Aluminum 3 Blade Blackmax 13x21P Prop. Its hard to bring the Boat on Plane. WOT 5600rpm.
Someone told me switch to a 4 Blade. Would you change also the Pitch. I dont care about highSpeed i yust want quick Plane.
Would you go with higher Pitch on a 4 Blade ?
Those look like fairly heavy boats for a 21P prop on a 60CT. I think a 4 blade would help, but I would also drop down to at least a 19" pitch, maybe even a 17" to get those RPMs up to 6000 at WOT with an empty boat. I think it needs the lower pitch more so than a four blade personally. Even if the boat can push 6000 RPM with a couple people it's not a bad thing, and it will get you on plane way faster. That's what I'd do!
Thank you!
@@vetdoc35happy to help!
Outstanding information Tom, and caputation queen. It's almost shameful the expense of a stainless prop and the added potential damage they can cause.
Questions:
How much of performance loss can I expect from prop damage like not smooth blades?
Are 4 blade props best for top end performance?
Does 3 or 4 blade props do the best reverse handling.
There used to be a local prop shop near me for decades, which is nla. When should a prop be restored? What are things to look for besides decreased performance?
I try to keep an extra prop and hardware onboard bc you never know right. I saved the day of fellow boaters having extra sheer pins, plugs, and hose.
Great questions! It seems to be that a little chewing on the ends of the props doesn't change things terribly, but then a little more damage and you may start to see some speed loss, slippage, and abnormal vibration. On a pontoon boat the speed loss may not be noticeable until there's significant damage compared to a planing style hull. I find that three blade stainless props will yield best top speed. They allow for larger diameters and each blade can have a bit more cup to them. Obviously, there will be others out there who swear by four blade...so I'm thinking this is a "to each their own" scenario, and different hull/motor combos might react differently too. Four blade props should do best for grabbing water at the dock for fine tune handling, reversing, etc.
If there's anything more significant than what I can touch up with a hand file then I would say it's time to have it restored. Things can get out of balance if you try to fix majorly damaged blades. I think the biggest signal that it's time to have it restored or replaced is when you're feeling the abnormal vibrations or shaking at certain (or all) RPMs. When I knocked most of a blade off on the river a couple years ago the boat would run slower but ok at certain RPMs. A little higher or a little lower than that sweet spot and it felt like the whole boat was going to shake apart! We got home ok, but had to swap that prop out right away!
Im only getting about 5000 to 5200 out of my 90hp Mercury in my 17 foot flats boat at 30 mph at full throttle when i put the trim tabs up the boat starts to porpois but i pick up speed. im running 19p prop should i go down to 17p?
Yes, I would drop down in pitch to get those RPMs up, assuming it's a four stroke. You may need to check where your tilt pin is at in the lowest position. Sometimes there's a pull pin or bolts that limit the amount of negative trim the motor can get. Porpoising is usually from not enough negative trim or not enough weight in the bow. You might need to keep those trim tabs down just a bit to limit the porpoising. Either way, I'd want to get those RPMs back up in the operating range which should level out all around performance with whole shot and top speed.
Would the rpms be affected by the pitch even when running the motor out of water with muffs on?
No, it really should not have any impact as there is little to no resistance to the motor/boat from the air. It's the load from the motor pushing the boat through water with a load that impacts the RPMs the most.
Hi, can you help me choose my proper propeller for mi Boston whaler dauntless 2001 with 125hp Mercury 2001 2 stroke
I would run it through the same steps discussed in the video running it wide open throttle paying attention to the tachometer and where the RPMs are in relation to the recommended range for that motor. You can go check out Mercury's Prop Selector to get a start too.
Hey Tom, I’m new to owning a boat and looking for advice on my new to me(used ) pontoon. I just watched your video and I’ve learned a little from it but looking for more clarification. I have a 21ft pontoon with a 75 hp merc 2 stroke. I’m only able to run at best 17 mph at 5000 rrpms. I’m also having a problem with the pontoon plowing through the water and unable to plane on top of the water. Currently running a 15 pitch prop and was advised to possibly look at changing it as well as getting a hydrofoil Any advice? Thanks
Looks like a 75 hp (1990-2005 years, non optimax) should run 5250 at wide open throttle with an empty boat. You could look to drop to a 13 inch pitch, but might have to watch your RPMs if you’re alone at wide open…however it’ll probably help a lot with when there’s a load of people and it might help with torque to get the bow up a little when trimmed up. A hydrofoil would help too, but not a fix for every boat. It’s a lot of boat to move for a 75 hp so I’m not sure you’ll see a big speed change or improvement either way.
@@tomspontoons thanks for the feedback. Loaded or unloaded (people or gear) it will only hit 5000 rpms. I put a hydrofoil on today and ran it, no improvement. I still can’t get the front end up on the water. I’m assuming the front furniture is too heavy for it. I was hoping to overcome that by the help of a hf and a new prop. I can’t afford to build the motor or buy a bigger one for now so I will try a prop next. So my question now is if I’m trying to gain top end speed do I go to a higher pitch or lower, to the 13 ?
@@MrCornbread1980 I think you’re pretty much seeing your max speed. Lowering in pitch would get your RPMs up slightly, but I don’t see that making any changes to top end speed. There’s a point with every pontoon boat or other non-planing hull where the motor just can’t move enough water to make the boat go faster, despite RPM changes. The boat just doesn’t lift enough compared to a planing hull like a fishing boat or speed boat.
Hello Tom I have a 24’ pontoon boat with a 75 Yamaha at WOT tac 3500 rpm 21mph the prop is a 125/8x21-k could you give me bast way to to up the rpm mph ?? Thanks Bill
Is it a two or four stroke? Assuming your tach is accurate that's way low for either 2 or 4 stroke motor. You'll want to drop in pitch...remember that each inch you drop in pitch is going to add about 200 rpm to your WOT. Also, make sure you're testing those numbers with an empty boat...not a boat full of people and gear!
Thanks I thought the pitch was to high so a 17p would probably work better ? Thanks Bill
@@mrbowfam dropping 4” would get you to the 4300 rpm range. If it’s a two stroke I’d still want to see it higher. You might end up all the way down at a 15” or even 13” depending what motor you’re running and the specs for WOT operating range. Super common for pontoons to run those lower pitch props!
@@tomspontoons thanks Tom yes it’s a two stroke 75 the boat is 1850 dry ! Do I stay with the same diameter at 12 5/8 ?? Thanks again
@@mrbowfam That's not a super common motor around where I'm from! It looks like it should run anywhere from 4500 to 5500 WOT range from what I found online. The diameter will likely change a little, but I wouldn't be concerned about the diameter. I would probably drop right down to the 13" if it were my boat to try to get those RPMs up in the healthier range!! Not sure you'll see a speed change, but all around torque and control will improve, plus it'll be better for the engine to get the proper high RPMs.
Awsome knowledge well tought
Thank you! Hoping it helps some folks out who aren’t sure where to start.
What if I cant read the number on the prop? I have 2007 24ft manitou 50 HP Evinrude 2 stroke. I just want to cruise on speed
Evinrude props are often labeled on the backside where the exhaust comes out. It may be covered by a nut and washer or just dirty from exhaust. Did you check there?
Otherwise you’d need to have a prop shop take a look and they should be able to tell you. If it were my boat, that size with that HP motor I would probably run a 10” or 11” pitch.
@@tomspontoons I did not I’ll take a look thanks
Very good video
Thanks so much!!
Need help !! I will get a new pair of Suzukis DF 150 APX for a boat AS MARINE 26 GL. I need a set up for speed weight is 5700 pound wet with fuel , water etc. What kind of props du you recommend? Thank`s for help
Oh man, that’s far beyond my scope of rigging!!! I would call the boat manufacturer first to see what they recommend, then the dealer to see what’s worked on the other boats they’ve rigged similarly. Then search the outboard manufacturers websites for the testing they’ve done with different boats and motors. From that research you should be able to come up with the information you need to make the smartest purchase possible!! Sorry I can’t be of more specific help on this one!
@@tomspontoons Thanks for your answer, but the manufacturer doesn´t test the twinn rigging. But thanks, It seems I have to get the long way and check by myself dif. setups.
@@7markshark that’s wild that they don’t offer some info. I’d also check with other boat manufacturers of similar hulls and motor setups before making the purchase of two stainless props!!
DUDE! Thank you!
Happy to Help!!!
I’m hoping you can help me. I’ve made tons of phone calls. My tack doesn’t work. I have a 1993 four winns horizon 190 with a 5.0L Volvo penta with a OMC cobra standard outboard (not the xs) I have no idea what my RPMs are. The prop on the boat when I purchased was a 15x17 hole shot is good pulls tubes nicely, but my top speed is only about 30-35 mph according to what I did find I should be able to reach 46-50mph. I would love to have a good holeshot. Still pull tubes but I really want to increase my top end speed. Again I don’t know what my RPMs are. Please help
Best bet is to wire in a new tachometer to see if your tach is just bad. Only a few wires to switch over to the new tach. Without knowing RPMs there’s not much else that you can do. Sounds like you’re probably running a little low of pitch if you have good wholeshot but slow top end. Worst case, might have to have a repair shop take care of it.
Thanks, great job
Thank you for watching!
Great information thank you
Happy to help, thanks for watching!
I wish I would have found your channel sooner, I probably would have just bought an older pontoon instead of building a barrel boat.
Glad you found us now though!! There’s always the option to build another out of an old pontoon!!!
Propeller selection! The most accurate and simple method
-> th-cam.com/users/shortsHpxgtUxJOpQ
lmao that intro tho. haha
Glad you got a kick out of that!!
awesome presentation. every man needs a smart chick in the background
She’s got me covered!