Appreciate the video. I have a 2006 Tohatsu 25hp 4 stroke EFI. ince I’ve bought it, it has been in the shop after each trip to the lake. The newest issue was when it was idling in neutral and abruptly died and shut off, no engine stutter or anything. Never have been able to restart the motor, It’ll crank (electric start) but no ignition. I replaced the kill switch, fuel hose/ primer bulb, and spark plugs. I have fuel pressure out of the fuel pump in the rear of the motor, and the fuel tank is vented. I’m going to check fuel rail next. I have no clue what the problem is though. Impeller and engine oil are also good. I just don’t want to keep taking the motor into the shop and waiting several weeks and paying tons of $$$. Thanks in advance
@@omieyouknowme the issue was the high pressure fuel filter was disintegrating sending debris/water into cylinders. That’s been replaced. Now it’ll randomly not be able to accelerate past low to mid RPMs when in forward gear as if there was a fuel leak or water in the lines. I think water keeps getting in the lines even though it’s kept in a garage and no water is being introduced to it while on the lake. I’ve had the VST cleaned and reassembled by a mechanic twice now. Each time it’ll run good once then start again. Don’t know why this keeps happening
@@sportsandhobies check the vst needle seat and low pressure fuel pump outlet pressure. The low pressure pump will put out 3psi give or take to fill the vst. If that's good take vst top off. Attach a spare line and blow air in it. You should be able to blow pretty well then raise the needle up and close it. Make sure blowing nd closing. If you are unable to blow into it remove needle, blow air pressure from inside out may be debris in the needle seat inside you can't see. Replace all fuel lines from low pressure filter to vst. Replace the low pressure filter assy if need it's cheap 15$. This sounds like you are starving for fuel from low pressure pump
@@sportsandhobies also just dawned on me. High pressure fuel filter falling apart will send debris down to injectors. This is a deadhead system, so any gunk will be at injectors. Did you remove injectors and inspect the filter on each injector. Did you blow out line from high pressure fuel filter to injectors. Fuel lines will degrade using ethanol in these motors.
@@omieyouknowme Tohatsu outboard does not get gasoline into the cylinders. The injector, ecu, spark plugs are intact. When I pour gasoline into the pistons, it works a little. When I press the starter, oily gasoline comes out of the exhaust. Could the high pressure pump have malfunctioned? How can I test it? Greetings from Istanbul, Turkey..
I'm sorry. I sold the motor and boat recently. The tiller was not bad, a 3/8" 2x4 aluminum plate was adapter. Bolt tiller to it then raise it up 1" bolt it to engine. The shift cable from Honda was used for throttle and a new mercury throttle cable was used.for shifting. Had to drill a new hole in the motor side for a shorter shift and throttle movement. All in all it works great. A tohatsu handle is probably cheaper and easier and can be found in eBay often. Honda tohatsu do share parts for some motors and larger tohatsu are Honda's
@@malcolmlund7938 no other way around. All aftermarket pumps draw to much. Not paying 700$ for OEM pump. I modified the relay to drive aftermarket pump instead
@@omieyouknowme I wonder if Quantum is aware of this? Hopefully they would FIX it. People could get the word out by leaving comments on Amazon, and maybe the Quantum website feedback.
@@malcolmlund7938 I contacted them about this issue. Believe they updated their site to exclude this motor. Believe all aftermarket pumps come from same factory in China and just get different labels.
The fuel system is a dead head design. I will have to check the manual, I sold the motor. But if memory is correct fuel comes out of pump into fuel cooler then filter. There is a T fitting before the filter and that outlet from T goes into regulator. This is pretty simple it pressurizes the line and filter and what ever is not need goes thru t and is regulated back in vst
How does all this work on a recoil start? I have a 2006 25EFI that I picked up that was sitting a long time. I know it has spark and compression because I started it with starting fluid. No fuel. I took of the low pressure fuel filter and cleaned it all out, changed gas, changed tank bulb and line. I am looking for the next step in figuring this out. Any suggestions would be appreciated. You seem to know your way around these motors quite well. Thanks in advance.
@@omieyouknowme I should have been clearer. I was wondering where the 12V came from and then realized it was generated it by the stator. It's been a long time since I worked on anything like this so I am rusty. Never did anything with an outboard or EFI. I took it apart and there were clearly signs of fuel crystallization. The rotor didn't budge with a dental pick or when I supplied 12V at 5A. No since I don't have a starter or battery, would I need to add a battery to work with this circuit or what other way could I be de-risk my ECU?
@@homesteadfromscratch I would then also replace the high pressure fuel filter too, I used a napa one for 5$ vs the 40$ OEM one. The stator generates ac power for ECU which has diodes to provide 12v for motor. My circuit requires output from the secondary stator. You should see the three pigtail connector on starboard side, you should be able to add a rectifier and grab power from there. Rectifier can be bought.on Amazon or eBay for after version
@@omieyouknowme First of all, I appreciate immensely you taking the time to help me. It has been a $$saver. Those are good ideas. Still figuring where that high pressure filter is located, but I believe it is below the VST. I will work on adding the rectifier.It seems like a good way to eliminate the risk. FYI, I did as a last effort, I took a soup can and filled it with SeaFoam and set the whole pump in it. After about an hour I took a flat dental pick and was able to move the impeller a bit and just wiggled it back and forth and then hooked up the 12V and after a few seconds it broke loose. I put it all back together and primed it up but needed a little starting fluid to get it running long enough to really get the fuel to the injectors. So it is running and seemingly pretty reasonable (at least in the barrel)! I will run some SeaFoam through the tank once I get the new filter. Thanks again!
Tohatsu outboard does not get gasoline into the cylinders. The injector, ecu, spark plugs are intact. When I pour gasoline into the pistons, it works a little. When I press the starter, oily gasoline comes out of the exhaust. Could the high pressure pump have malfunctioned? How can I test it? Greetings from Istanbul, Turkey..
Remove the connector and apply 12v to pump manually and try starting If no fuel then yes pump is bad. Check fuel.pressure when applying power on shrader valve should be 43psi Sounds like you have spark but no fuel. I suspect bad high pressure fuel pump make sure low pressure pump is also working it should fill the vst quickly when cranking
Also check your oil, is it over filled. When your put gasoline inside cylinder directly you can dry it out of oil for lubrication and some of it can go inside oil pan and exhaust.
@@omieyouknowme In this engine, apart from the normal injector, there is also an air injector. I do not know how to control the air injector. The compressor is very good. What does air injector do? Could the cause of the malfunction be the air injector? Thank you very much.
@@ayhankucukozer1478 air injector? The engine is very basic If you put fuel into cylinders and it tried to fire that means you have air and spark. What's missing is fuel. There is air valve but that is attached to throttle body to regulate low speed idle and cold engine warmup. It will not prevent engine from starting. From what you said it sounds like fuel pump is not getting power or fuel pump is not working. When trying to start engine, there should be 13v at fuel pump at connection. If you have 13v and still no start, then apply 12-13v to fuel pump manually and see if it starts. If no start you have bad fuel pump.
@@omieyouknowme Greetings my dear friend.. There is a 50 hp thatsu engine. 3 injectors are intact, the brain is intact, the fuel pump is working... but I think there is no fuel reaching the pistons. It works when I spray brake lining spray inside. I am a mechanical technician myself. Apart from the 3 injectors of the engine, there are also injectors inside the compartment called the log, I think they adjust the air and gasoline mixture. Could it be one of these? What is your advice? I wish you a good day... From Tuzla, Istanbul Greetings... Gasoline reaches the injectors. In addition to the fuel pump, there is also a pressure box that pushes the fuel forward.
Injectors fuel pump idle valve all run off same 12v line. Removed one injector plug cranked it saw 12-14v in that wire. Then plugged a diode into that plug pulled again the diode lit up. Injectors where firing. You can rent or buy injector noid testers for 10$ they do same thing. Spark pull the spark plug and wire. Leave wire attached to plug zip tie threads if plug to nearest ground or bolt. Cranked over saw spark. Done deal.
That that left the high pressure pump and air, since it was sucking in air the fuel pump was only cuplrit. I also found the wires inside the vapor canister where corroded and were arcing I inside fuel possibly. Had to pull those wires and heat shrink them to re insulate
@@omieyouknowme did you have to go with the original ome part mercury fuel pump or did the quantum pump burn up your ecu I'm curious because I have one coming tomorrow. My engine is a 2010 efi 25 hp. If it provides to much amp do you think it would be ok to run it for like 2 minutes just to see if the fuel pump is the problem with the engine then turn off or would it burn up the ecu when I try to start it? My pump wouldn't move when I tried cranking it or by hand too
@@shortdrawwhitetail1222 the quantum pump would run fine for two minutes, but I would not run it more than a test. I did not buy the OEM pump it was more than what I paid for motor. But the replacement ECU cost me.
Start with basic. Does it have spark? Get a can of starting fluid and a quick 1 second squirt inside intake and try to start. If it fires for few seconds you have spark and no fuel.
Then if no fuel can you rig up a 12v power supply to high pressure fuel pump, the yellow connector. Apply 12v does it run and shut off and not restart them pump is giving bad. If it runs and restarts.and stays running your ECU is about.to.go.out
@@omieyouknowme It will run fine in the tub or on the muffs and then when i do a lake test it will run fine and then when I shut it off it will start several time and then i do this run it some up the river and back a ways and turn it off near the launch so if it does not go im not stranded and every once in a while it will not restart .If i let it set a while it will start.I think its fuel starved but next tim out in taking something to check spark and fuel pressure if i can fine a fp gauge locally
@@terrymunn1224 get a cheap tire gauge from Walmart for 3$ stick it on shrader valve when motor is running to check fuel pressure, should be 40psi Fuel starvation hmm. Have you taken vst tank out and cleaned it? If you can get a vacuum pump gauge, stick the outlet from low pressure pump into gauge and crank engine, see if it's got at least 2 psi. If so low pressure pump is good. I had a piece of fuel line break off from hose and it went into vst and plugged the needle caused fuel starvation between low pressure pump to vst. Motor would run great at idle and 1500rpm. Anything more it would starve of fuel. Crank crank and crank to slowly fill VST then it runs. Run it at 2500rpm and it would die again
I am cleaning the vst right now and it was dirty and screen looked plugged.I will remove the low pressure pumpump and see if it ir serviceab le as well. @@omieyouknowme
Vapor separation tank. It houses the high pressure fuel pump a float so low pressure pump feeds it. It also cools the fuel. You can also look for surge tanks commonly used in efi kits
@@customdecals3983 leave the screw go get another. To remove that lower cover you have remove the motor. The bolts for motor are from the bottom you can remove the 4-5 10mm bolts for lower plastic cover.you will see it more clearly why.
Appreciate the video. I have a 2006 Tohatsu 25hp 4 stroke EFI. ince I’ve bought it, it has been in the shop after each trip to the lake.
The newest issue was when it was idling in neutral and abruptly died and shut off, no engine stutter or anything. Never have been able to restart the motor, It’ll crank (electric start) but no ignition. I replaced the kill switch, fuel hose/ primer bulb, and spark plugs. I have fuel pressure out of the fuel pump in the rear of the motor, and the fuel tank is vented. I’m going to check fuel rail next. I have no clue what the problem is though. Impeller and engine oil are also good.
I just don’t want to keep taking the motor into the shop and waiting several weeks and paying tons of $$$. Thanks in advance
If you have fuel pressure on rail is it 40-43 psi? Random shut down are the hardest, when it is running is the ECU hot?
@@omieyouknowme the issue was the high pressure fuel filter was disintegrating sending debris/water into cylinders. That’s been replaced.
Now it’ll randomly not be able to accelerate past low to mid RPMs when in forward gear as if there was a fuel leak or water in the lines. I think water keeps getting in the lines even though it’s kept in a garage and no water is being introduced to it while on the lake. I’ve had the VST cleaned and reassembled by a mechanic twice now. Each time it’ll run good once then start again. Don’t know why this keeps happening
@@sportsandhobies check the vst needle seat and low pressure fuel pump outlet pressure. The low pressure pump will put out 3psi give or take to fill the vst. If that's good take vst top off. Attach a spare line and blow air in it. You should be able to blow pretty well then raise the needle up and close it. Make sure blowing nd closing.
If you are unable to blow into it remove needle, blow air pressure from inside out may be debris in the needle seat inside you can't see. Replace all fuel lines from low pressure filter to vst. Replace the low pressure filter assy if need it's cheap 15$. This sounds like you are starving for fuel from low pressure pump
@@sportsandhobies also just dawned on me. High pressure fuel filter falling apart will send debris down to injectors. This is a deadhead system, so any gunk will be at injectors. Did you remove injectors and inspect the filter on each injector. Did you blow out line from high pressure fuel filter to injectors. Fuel lines will degrade using ethanol in these motors.
@@omieyouknowme Tohatsu outboard does not get gasoline into the cylinders. The injector, ecu, spark plugs are intact. When I pour gasoline into the pistons, it works a little. When I press the starter, oily gasoline comes out of the exhaust. Could the high pressure pump have malfunctioned? How can I test it? Greetings from Istanbul, Turkey..
Please make a video of switching over to tiller. Enjoyed this video
I'm sorry. I sold the motor and boat recently.
The tiller was not bad, a 3/8" 2x4 aluminum plate was adapter. Bolt tiller to it then raise it up 1" bolt it to engine.
The shift cable from Honda was used for throttle and a new mercury throttle cable was used.for shifting. Had to drill a new hole in the motor side for a shorter shift and throttle movement. All in all it works great.
A tohatsu handle is probably cheaper and easier and can be found in eBay often. Honda tohatsu do share parts for some motors and larger tohatsu are Honda's
Thanks for this. So, the pump you bought/installed drew the proper current and did not damage the computer? If yes, what brand was it?
@@malcolmlund7938 no other way around. All aftermarket pumps draw to much. Not paying 700$ for OEM pump. I modified the relay to drive aftermarket pump instead
@@omieyouknowme thanks so much - really appreciate your guidance!
@@omieyouknowme I wonder if Quantum is aware of this? Hopefully they would FIX it. People could get the word out by leaving comments on Amazon, and maybe the Quantum website feedback.
@@malcolmlund7938 I contacted them about this issue. Believe they updated their site to exclude this motor. Believe all aftermarket pumps come from same factory in China and just get different labels.
What connects to the fuel regulator?
The fuel system is a dead head design. I will have to check the manual, I sold the motor. But if memory is correct fuel comes out of pump into fuel cooler then filter. There is a T fitting before the filter and that outlet from T goes into regulator. This is pretty simple it pressurizes the line and filter and what ever is not need goes thru t and is regulated back in vst
How does all this work on a recoil start? I have a 2006 25EFI that I picked up that was sitting a long time. I know it has spark and compression because I started it with starting fluid. No fuel. I took of the low pressure fuel filter and cleaned it all out, changed gas, changed tank bulb and line. I am looking for the next step in figuring this out. Any suggestions would be appreciated. You seem to know your way around these motors quite well. Thanks in advance.
If you apply 12v to pump do you hear it running
If you hear pump running then pull in starter. If it starts then issue is ECU not triggering pump if pump does not run manually then it's shot
@@omieyouknowme I should have been clearer. I was wondering where the 12V came from and then realized it was generated it by the stator. It's been a long time since I worked on anything like this so I am rusty. Never did anything with an outboard or EFI.
I took it apart and there were clearly signs of fuel crystallization. The rotor didn't budge with a dental pick or when I supplied 12V at 5A.
No since I don't have a starter or battery, would I need to add a battery to work with this circuit or what other way could I be de-risk my ECU?
@@homesteadfromscratch I would then also replace the high pressure fuel filter too, I used a napa one for 5$ vs the 40$ OEM one.
The stator generates ac power for ECU which has diodes to provide 12v for motor.
My circuit requires output from the secondary stator. You should see the three pigtail connector on starboard side, you should be able to add a rectifier and grab power from there. Rectifier can be bought.on Amazon or eBay for after version
@@omieyouknowme First of all, I appreciate immensely you taking the time to help me. It has been a $$saver. Those are good ideas. Still figuring where that high pressure filter is located, but I believe it is below the VST. I will work on adding the rectifier.It seems like a good way to eliminate the risk.
FYI, I did as a last effort, I took a soup can and filled it with SeaFoam and set the whole pump in it. After about an hour I took a flat dental pick and was able to move the impeller a bit and just wiggled it back and forth and then hooked up the 12V and after a few seconds it broke loose. I put it all back together and primed it up but needed a little starting fluid to get it running long enough to really get the fuel to the injectors. So it is running and seemingly pretty reasonable (at least in the barrel)!
I will run some SeaFoam through the tank once I get the new filter. Thanks again!
Tohatsu outboard does not get gasoline into the cylinders. The injector, ecu, spark plugs are intact. When I pour gasoline into the pistons, it works a little. When I press the starter, oily gasoline comes out of the exhaust. Could the high pressure pump have malfunctioned? How can I test it? Greetings from Istanbul, Turkey..
Remove the connector and apply 12v to pump manually and try starting If no fuel then yes pump is bad. Check fuel.pressure when applying power on shrader valve should be 43psi
Sounds like you have spark but no fuel. I suspect bad high pressure fuel pump make sure low pressure pump is also working it should fill the vst quickly when cranking
Also check your oil, is it over filled. When your put gasoline inside cylinder directly you can dry it out of oil for lubrication and some of it can go inside oil pan and exhaust.
@@omieyouknowme In this engine, apart from the normal injector, there is also an air injector. I do not know how to control the air injector. The compressor is very good. What does air injector do? Could the cause of the malfunction be the air injector? Thank you very much.
@@ayhankucukozer1478 air injector?
The engine is very basic
If you put fuel into cylinders and it tried to fire that means you have air and spark. What's missing is fuel.
There is air valve but that is attached to throttle body to regulate low speed idle and cold engine warmup. It will not prevent engine from starting.
From what you said it sounds like fuel pump is not getting power or fuel pump is not working. When trying to start engine, there should be 13v at fuel pump at connection.
If you have 13v and still no start, then apply 12-13v to fuel pump manually and see if it starts. If no start you have bad fuel pump.
@@omieyouknowme Greetings my dear friend.. There is a 50 hp thatsu engine. 3 injectors are intact, the brain is intact, the fuel pump is working... but I think there is no fuel reaching the pistons. It works when I spray brake lining spray inside. I am a mechanical technician myself. Apart from the 3 injectors of the engine, there are also injectors inside the compartment called the log, I think they adjust the air and gasoline mixture. Could it be one of these? What is your advice? I wish you a good day... From Tuzla, Istanbul Greetings... Gasoline reaches the injectors. In addition to the fuel pump, there is also a pressure box that pushes the fuel forward.
How did you check spark and injectors
I have a 2007 tohatsu 25 4 stroke that wont fire
Injectors fuel pump idle valve all run off same 12v line. Removed one injector plug cranked it saw 12-14v in that wire. Then plugged a diode into that plug pulled again the diode lit up. Injectors where firing. You can rent or buy injector noid testers for 10$ they do same thing. Spark pull the spark plug and wire. Leave wire attached to plug zip tie threads if plug to nearest ground or bolt. Cranked over saw spark. Done deal.
That that left the high pressure pump and air, since it was sucking in air the fuel pump was only cuplrit. I also found the wires inside the vapor canister where corroded and were arcing I inside fuel possibly. Had to pull those wires and heat shrink them to re insulate
What is the part number for the napa oil filter? Thanks for the video!
I won't be near the motor for few weeks. You can cross ref.existig filter on wixx filter that gets you the napa #
@@omieyouknowme Thank you!
Did you try turning the blade in fuel pump with a small tool by handl? or do you have to run power to test if blade is turning?
I applied power and it did not even twitch. Tried a small pick to move the blades it was frozen from something
@@omieyouknowme did you have to go with the original ome part mercury fuel pump or did the quantum pump burn up your ecu I'm curious because I have one coming tomorrow. My engine is a 2010 efi 25 hp.
If it provides to much amp do you think it would be ok to run it for like 2 minutes just to see if the fuel pump is the problem with the engine then turn off or would it burn up the ecu when I try to start it? My pump wouldn't move when I tried cranking it or by hand too
@@shortdrawwhitetail1222 the quantum pump would run fine for two minutes, but I would not run it more than a test. I did not buy the OEM pump it was more than what I paid for motor. But the replacement ECU cost me.
@@omieyouknowme thanks your video just save my butt brother.
I have the same motor and it will run a while and then when I shut it off it will not start.Any ideas what it could be
Start with basic. Does it have spark? Get a can of starting fluid and a quick 1 second squirt inside intake and try to start. If it fires for few seconds you have spark and no fuel.
Then if no fuel can you rig up a 12v power supply to high pressure fuel pump, the yellow connector. Apply 12v does it run and shut off and not restart them pump is giving bad. If it runs and restarts.and stays running your ECU is about.to.go.out
@@omieyouknowme It will run fine in the tub or on the muffs and then when i do a lake test it will run fine and then when I shut it off it will start several time and then i do this run it some up the river and back a ways and turn it off near the launch so if it does not go im not stranded and every once in a while it will not restart .If i let it set a while it will start.I think its fuel starved but next tim out in taking something to check spark and fuel pressure if i can fine a fp gauge locally
@@terrymunn1224 get a cheap tire gauge from Walmart for 3$ stick it on shrader valve when motor is running to check fuel pressure, should be 40psi
Fuel starvation hmm. Have you taken vst tank out and cleaned it?
If you can get a vacuum pump gauge, stick the outlet from low pressure pump into gauge and crank engine, see if it's got at least 2 psi. If so low pressure pump is good.
I had a piece of fuel line break off from hose and it went into vst and plugged the needle caused fuel starvation between low pressure pump to vst. Motor would run great at idle and 1500rpm. Anything more it would starve of fuel. Crank crank and crank to slowly fill VST then it runs. Run it at 2500rpm and it would die again
I am cleaning the vst right now and it was dirty and screen looked plugged.I will remove the low pressure pumpump and see if it ir serviceab le as well.
@@omieyouknowme
What is the "VST"?
Vapor separation tank. It houses the high pressure fuel pump a float so low pressure pump feeds it. It also cools the fuel.
You can also look for surge tanks commonly used in efi kits
I have the same motor but can't locate the mechanical fuel pump? can you tell me the location? thanks
Mounted on valve cover back of motor. Look at valve cover where oil filler cap is right below square box with fuel going in and out
awesome, found it but can't get that lower cowling off? any tricks? I dropped the fuel pump screw in there? thanks@@omieyouknowme
@@customdecals3983 leave the screw go get another. To remove that lower cover you have remove the motor. The bolts for motor are from the bottom you can remove the 4-5 10mm bolts for lower plastic cover.you will see it more clearly why.