Small Engine Repair: Checking a Vacuum Fuel Pump / Fuel System on a Kohler V-Twin Engine
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- เผยแพร่เมื่อ 3 มิ.ย. 2011
- Visit www.thesmallengineshop.net
*Always follow the instructions in your repair manual when doing repair or maintenance work on Outdoor Power Equipment. Manuals can be found at the manufacturers website.
Checking the fuel system, and vacuum fuel pump on a V-twin 25HP Kohler engine involves checking the fuel lines that attach to the pump, and checking fuel flow. The first step is to check to make sure fuel can flow from the gas tank to the fuel pump. To do this, disconnect the fuel line from the vacuum inlet fitting on the vacuum pump. Take the fuel line and lower it to a point that is below the fuel tank and see if gravity will cause fuel to flow from the tank through the line. If fuel flows, than the line is clear. If fuel will not flow, than check the fuel filter to see if it is restricted. Also check the fuel tank shut off valve if the tank is equipped with one. The valve may be in the off position, or dirty and restricted. Check the fuel tank cap to see if the vent on the fuel tank cap is plugged. If the fuel tank cap vent is plugged than fuel will not flow out of the fuel tank.
Next, check the pulse line on the vacuum pump. Make sure it is connected correctly to both the vacuum pump and the engine crankcase. Also, make sure the engine is not overfilled with oil and the pulse line is not filled with oil. If the engine oil is overfilled with oil, than oil can make its way into the pulse line and block the pressure necessary to operate the fuel pump.
The next thing to check is the fuel line from the vacuum pump to the carburetor. To do this, take the line off and make sure the line is in good condition, and there are no restrictions in the line.
The final check is to make sure the vacuum pump is pumping fuel. Disconnect the vacuum pump outlet line where it connects to the carburetor inlet, and turn the engine over. If fuel flows from the vacuum fuel pump, than the pump is working. Kohler does not provide a more precise way of checking the vacuum fuel pump, and they say if you get fuel flowing through the pump when the engine is turned over, than the fuel pump is working correctly. Kohler does say the vacuum fuel pump should pump a minimum of 2 gallons of fuel per hour with a pressure at 0.3 psi and a fuel lift of 24 in, but they do not give you a method to check these specifications. - ยานยนต์และพาหนะ
I had a ch 20 S Kohler V Twin, it was cutting out and shut off at high speed operation, I tried another carburetor, fuel pump, checked the fuel filter etc.(before watching this video) The engine idled fine all day. It was definitely a fuel starvation problem. After watching this video, it stated check the oil level. Well the engine I was working on had WAY to much oil in the crankcase. The oil level is CRITICAL to the operation of the fuel pump since it works off the crankcase. After draining about 1 quart of oil out, the engine ran PERFECT. If anyone has a similar problem check the oil level first. GREAT VIDEO!
You saved the day. You are the only person to mention the problem with too much oil affecting the pulse line. I had replaced my fuel lines, the filter and the fuel pump, but never thought to check my oil level. Sure enough, it my oil was a bit past the full mark. I drained it down to just below full and now everything works perfectly. THANKS!
Learn something new everyday. Never thought to check my oil level. Didn't know that that could affect the vacuum
Best 8 minute video on V Twin fuel system's DONE!!.. those long 15/20 videos Chit Chat drive me crazy.. again thanks for the informative video...
FINALLY! After watching numerous videos. Finding one, yours, that actually addresses the problem I'm having. Your video may not fix my problem. But it gives me a great place to start. Thank you.
Hands down the most informed and to the point in layman's terms tutorial on the fuel pump. Thanks for "nothing but the facts".
10 years and Im just now finding this video?!? Perfectly narrated and illustrated. Very simple to follow along. Thank you.
That was mighty helpful. I'll be out there at 7:30am using this method. Thanks loads.
Hey, that's gonna be tomorrow! I hope it went well for you! Thanks smallengineshop. Extremely helpful video!
Been working on fuel issue all day. Your video helped me within 2 minutes. Thanks a million!!
Thanks for the great video! I recently rebuilt the Walbro carb on my 31F series 17HP Intek, and it ran great for a couple of months, then started acting up again. I checked spark, air, and fuel, and everything seemed fine, except that it would start spitting and sputtering after running for a while, and then sometimes stop. After a minute it would crank, and then go for some more. I saw 2:52, walked to the garage and opened the fuel cap, and was greeted by the hissing of air rushing into the collapsed fuel tank (it's hidden inside the frame of the mower) and a loud pop as the tank flexed back to it's normal shape. That little diaphragm actually pulls hard enough to collapse a heavy plastic tank! The engine starts and runs fine now with the cap partially opened, I'll have to replace that soon. Anyway, thanks again, your video saved me from tearing my hair out!
A great example of step-by-step, Point A>Point(x) troubleshooting. I use the same principle whether it's gas or electrical flow. Start at the source & test every junction in sequence until you find the failure. Once you've built up your knowledgebase, then you can start "most likely problem" troubleshooting. :)
And thanks for having your lighting set up well!
Excellent. No wasted time, no needless music, just the facts and demo. Thank You.
I expect this will be the same check procedure on my 22HP B&S with similar pump. Takes a lot of cranking but then it runs fine. New everything but Carb, pump and hoses..
Thank you. Your video is the first one I have seen that shows a comprehensive fuel delivery troubleshooting everything. Most focus on the fuel pump. Been chasing my problem and ended up being a clogged vent on the gas cap.
Thank you for a great video, I will definitely follow all you steps and am feeling up to the task. You have great patience and remarkable calmness (a trait we would all love to have) when gas started coming out of the hose toward the end of the video.
Much appreciate you posting the video and documenting the troubleshooting steps well. I've not dealt with a vacuum fuel pump before and this helped with some of the diagnosis of a tractor I'm working on. Thanks!
Nice job, thanks. Excellent camera work, tool selection and narration!
As others have mentioned, could troubleshoot in a way that avoids air filter removal, but it's always good to have a visual check of the entire fuel line and carb.
Those notes: (thanks wonka & quantumrift)
1. Vacuum gauge is a good, inexpensive tool to help with troubleshooting
2. Can remove fuel lines from fuel pump line to save time and add a small piece of spare fuel line to do checks, if fuel pump is fine, then you know it is a line condition issue or obstruction
3. If gas cap vent is an issue, a tooth pick can be the right tool for a fix
Any votes on how long most fuel lines last before their condition affects performance in hot, humid climates? 3, 5 or 7 years?
Excellent video! Well photographed, showed all parts perfectly, great commentation with a very good description of just exactly how to check the pump to be sure of good working order without too much useless vocabulary. Even telling me the size socket to use! Thank you for putting this here!
Thanks
Great video! Thanks for doing this video!
Excellent and thorough. Brief and clear, thanks!
Excellent video and well put together. Outstanding camera work as well as a concise and succinct commentary. Wish all DIY videos were this good! Great job!
Thanks
Thanks for explaining the different openings on the fuel pump. Had hoses wrong. Fixed now. Much appreciated
very informative, educational video. Thanks for the clear, concise, no nonsense presentation.
Hey just wanna let you know you did a outstanding job you’re to the point and explains it very well. Thanks for your help
Nice presentation of the troubleshooting flow chart! I went at it from a different approach,based on my personal mechanical knowledge, but didn’t think about the possibility of the crank case being over full causing this issue🤯. Thanks! That’s the first thing I’m going to look at tomorrow morning. I’ll be back with a comment,if my problem is solved by this inspection.
One of the best videos on TH-cam! Thanks!
Thank you for making this video!
Thanks for the video.I see a lot of people asking why take off the air filter assembly. I’m glad you did! My was already off and I was ready to buy a new fuel pump.I am working on a Honda GX610 and it keeps cutting off starving for gas. Now I know the lines, filters, and fuel pump are all clear and working properly, I KNOW now to keep searching for that low oil sensor. I’ve bought a new one but can’t find the one on the engine.Anyway, Thanks Again!
I'm usually critical of video's but this one is great. Thanks for not having any wasted time.
Thanks, checking a motor fuel pump on a Hasquavna ride on mower, this video great, so clear!
Nice. Thanks for the walk through!
Very helpful video. Thanks.
Great video, lots of usefull information and no wasted time talking about crap that has nothing to do with mowers. You should teach a class on how to make videos for TH-cam about mowers. There is more useful information in your eight minute video than I have found in hours of other videos. A lot of people that post videos about mowers waste so much time doing ignorant crap that I turn the video off before they ever get to anything useful. And yes, Taryl fixes all, I'm talking about you.
I’ve been searching for this. Thanks.
As many others have said, nicely done. I'm checking my fuel pump tomorrow. It runs when I drizzle gas into the evaporation chamber before the carburetor. If the fuel pump is not it, it's probably jets, also simple.
Thank you so much for making this!
Very helpful video. Thank you for posting it.
Simple and straightforward!
Very well done. Most on TH-cam are not watchable due to such bad video. Yours is very professional looking and informative. Thanks.
oh thank you so for this video, it helped me so much and yes, I did the work/checks myself.... now to get a new vacuum pump.
Thank you for clear explanation of workings.
Good video 👍 precise and to the point. Kawasaki fh 641 v have you ever heard of the fuel pump being relocated because the mower manufacturer put the muffler to close and causing vapor lock. This is on a snapper zero turn mower that none of the half dozen small engine shops in my area will work on. One mechanic told me there was a recall but nobody works on snapper because they don't pay the shops when they perform warranty work. The mower starts great when cold and will not start when hot
Very well explained. Thank you for sharing.
I have now signd up to your channel thank you for showing me good stuff.
Thanks brother you saved me a bunch o $$$
A very common, but not well known at all, reason for bad flow from the vacuum fuel pump to the carb is air in the gas line somewhere between the gas tank and the fuel filter. The line isn't "plugged" with dirt or debris. The air simply prevents the relatively weak vacuum pump (even when new) from being able to suck a sufficient quantity of fuel through the system per minute. Most often what happens is that the user runs out of gas, or gets to the point where then engine is sputtering from being starved. Gas is put in the tank, it starts, but air may be hiding somewhere in that long line on a zero turn. After 10 to 30 minutes it cuts out. Solution is simple but not OSHA approved. Blow into the gas tank while your face makes a tight seal so pressure builds up. This will clear out the line. (By the way to test a fuel pump just blow into its plastic tube that is ordinarily connected to the valve cover. If it totally resists you blowing into it, it's likely still good. This video explaining this which I found today was a revelation. Won't be buying an annual fuel pump. th-cam.com/video/eQf1BDmyUCw/w-d-xo.html
I like the way you make these steps simple and helpful, step by step to eliminate and find problem, good job.
I would have first checked the vacuum side with a VACUUM gauge first.
Thanks! Very helpful.
This video was very helpful. Why would some ‘dislike’ the video
Great video. I got lucky and loosened the fuel cap (JD X300) and it started. Checking the pump would have been my next step though.
good video. now i can test mine before just going and buying a new one. thanks
THANK YOU FOR YOUR HELP
Love your vid. Well explained thx for sharing
One thing you missed is that some tanks have a wire mesh screen mounted to the pick-up inside the gas tank, these can become plugged or actually collapse and restrict gas flow. This happened to my Simplicity it would idle but was not getting enough gas to run at higher rpms. After removing screen and installing a good inline filter the tractor runs great.
Thanks for the video!
Very cool. Well done. Thanks.
Excellent video.
Thanks brother. Great class!!!
Excellent video!
very well done. Thank you. I will be ordering a new fuel pump.
Real nice video though. Clear and concise.
Great video...I tested my pump as shown in the video, and everything worked as shown, but my problem continued, the engine would start up fine ...but only run for a minute or so, then die (as if it ran out of gas). Letting the engine sit for a while would then allow it to start up again for a minute or so. I watched a couple of videos and one video mentioned how you could tell if the pump was old by checking the small screen on the front of the pump....if it was black it was "old" if it looked metallic, then it was "new"....hmmmm I wonder?....so I got out some alcohol and a small brush and cleaned the screen from the outside (it was black and dirty) ....once cleaned the engine started right up ( as usual) but insteadf of dying out I mowed the entire yard with no further issues (about a 40 minute job)....so you may not even need a pump at all....you may only need to clean the small screen....worked for me !!! Give that a try !!!
Thanks for that tip.
How is your machine running this year? ,i jave tried everything so im gonna try the screen cleaning next after reading this
My problem on a 22HP Kawasaki in my X320 JD turned out to be a bad connector (12 Socket) with 3 yellow wires. One of these had low (10VDC) and was not opening the Fuel Shut Off Solenoid. I checked the solenoid direct from Battery. I went at the Connector (very small connectors) with Brakleen and plugged it back in and heard the Solenoid click. I had started at the solenoid checking connectors and voltage. There are 2 other connectors. One 5 pin, one butt connection at engine.
This after pulling the carb twice, blowing out line from pump to tank, replacing Filter, Fuel Pump and a lot of beer. Works perfectly now.
nice video very informative
Thank you for the great video. Last season I bought a new Ariens zero turn mower from Lowe's. It ran well at first. I fueled it up today and cut for about 3-4 minutes then it cut off and will not start. It only has 4.2 hours on it. Please advise. I took the fuel line off going to the fuel pump, held it down towards the ground and no fuel is coming out. I didn't go any further than that because it's a new unit. The 4.2 hours came from 2. something from last season and less than 2hr this season. Please advise.
Well done. Thanks.
That is MY mower. I bought it for $100 cause the owner didn't know how to change the $12 PTO switch.
I removed the deck, and just buzz around the 9 acres with it since it has a fast forward speed.
SIDE NOTE: Dig around your garbage and find a tin can that doesn't have sharp edges.
As usual...
THanks for THinking!
Nice video. Thank you.
Well done, thanks! I don't have a Kohler, but I can use these principles to check my fuel pump.
SpockMcoy Issmart Thanks for watching!
Fatboy, look at the lines. I've noted 3 on any I've worked on. 1 is from the fuel tank, 1 is out to the carb, 1 goes up into the engine, where the vac is drawn from. hope this helps.
Thanks for your clip you just saved me a ton of money thought the fuel pump was stuffed mean time it was the gardener over filling the mower with oil
Thanks for watching
Very helpful, good job.
very clear and helpful.
Subscribed!!! Excellent video
THANK YOU. for this Video. God Bless You>>!!
Thank you Sir. My issue was a gas cap not venting, so thank you for mentioning that!
How do you know if the gas cap isn't venting
@@user-iy1be6gj3k when you unscrew the cap air either blows out or sucks in. Makes a psst sound.
Very good video and explanation..
Thanks this video was very helpful
outstanding explanation, even I understand that, thanks
Great video and very instructive. Just curious where you got your hose gripping pliers, shown in the video?
great video.. helped me out
Thanks for posting this! Good work.
Very informative and helpful.
Thank you much
Thanks!
Very informative 👍
Thanks man. Great delivery and "if nots" thanks so much!! I should give you my money!! I'm subscribing
Thank you, I'm gonna try it
Very clear, very helpful. Thank you!
Thanks for watching!
@@smallengineshop What if I can't get fuel from the inlet line BEFORE the fuel filter. Clog in tank? You mentioned in tank shut off switch? Thanks in advance.
Thanks for the information. My father has a Kohler engine that is having problems but, I wasn't sure how to verify the operation of the fuel pump. I wasn't sure if the pressure was high enough. From what you said, it appears that the pressure isn't as important as the fact that an ample amount of fuel is flowing. I'll now focus on the carb float etc.
Thanks again.
Thanks for the video. I have a question the pump on my riding mower works fine I’m getting gas to the carburetor it turns but won’t start you think is the carburetor?
Thank u. verry helpful!!!
Very helpful info and clear instructions, thanks very much!
This is a “dam” good video.
Good video. This is a new one for me. Engines I've had before ran straight from the tank to the float bowl. Are these gadgets actual pumps, or are they just a vacuum fuel cutoff switch? I'm wondering because I have a Honda GC160 with a crankcase full of gas. Obviously the float needle failed to do it's job, but I'm wondering if this little gadget wasn't supposed to be cutting off the fuel before it even got to the carb. Anyone know?
Thank you well explained
How do you test this for one of the Briggs and Strattons with the fuel pump diaphragm built into the carburetor? The 42D707 models? (2280 E3 specifically).
I've already replaced the fuel filter, the carb gaskets, carb is clean, new diaphragm. Engine starts easily with Engine Starter fluid, and I can run it by spraying the carb with starter fluid, but when I stop, the engine stops running once it burns off the starter fluid. Seems to me it's acting like it isn't getting gas pumped into the carb? Gas flows through fuel line easily at least up until it gets to the carb. All carb jets are cleaned. Good compression in engine. I just can't figure out how to tell if the pump is actually working. Thanks!
Hi there. I followed these and all looks good. Riding mower still surges. If move gas throttle to mid or above runs more "stable". Drop below mid and starts to surge. Any thoughts are appreciated.
So helpful. Thank you for making the video. Helped us fix the problem on our mower. Subscribing to your Chanel now lol
Good clear and concise video. You instill confidence. I have a craftsman mower with a Briggs & Straton 18 HP OHV engine that will start well then after an hour or so it dies. The battery has just been changed to a new one but like I said the engine stopped after about an hour of use. This has been happening for a couple of seasons now. It is very temperamental.
Thanks
smallengineshop ive got a ? Could u email me i have this motor in a 20 hp and cant get it started ive had 3 engine shops look and none can figure out y it wont start
Very helpful!
Question for you: Should there be fuel flowing out of the pump without the engine running/cranking? Or would that be a sign of a bad diaphragm?
You would probably have some pressurized fuel in the line (as you did), but should it continue flowing once the pressure is relieved?
Having issues with fuel flowing out of the throttle opening on the carburetor after sitting overnight. Already took apart and cleaned the carb and float bowl, and that helped for a while, but still having the issue.
Thank you for the informative video!
Useful video - thank you. But I have a vee-twin Kohler with a pulse pump and it's filling the sump up with petrol, preventing the engine from starting. Does this mean that the valves in the pump are not working correctly and it is drawing the petrol straight into the engine ? In which case I need a new pump ?
The way he calls a push lawn mower a tractor is hilarious
This video is awesome. Just bought a used gt5000 and I dont think its getting enough fuel. The video should help me find the problem. Thanks.
Thanks buddy😎
Where did you find those pliers?
Excellent video, I was looking for information on vacuum pumps, thanks for putting this up.