Yamaha Outboard Low Pressure Fuel Pump Replacement 

Glad it was helpful!

Awesome, glad you were able to get this done on your own 👍🏽

These fuel pumps are all basically the same. hope it helps

thank you sir, what is the issue you have with yours?

Thanks for the tip!!

that sounds like a great setup, I will look into that. and yes ethanol really beats these components down

@@ReelTeaseFishing When 10% Ethanol was first introduced Lexus and BMW had 100K fuel related warranty problems. What few dealerships took fuel samples found up to 20-23% Ethanol when it's suppose to be 10%. Ethanol is a cousin of Alcohol and destroys common rubber. Yamaha and Mercury both suffered from the introduction of Ethanol as well as their customers.

@@robertjackson7590 ethanol, being an alcohol, chemical compound (-OH) naturally wants to attract another hydrogen thus causing H20. (Hydrogen Bonding) this is why ethanol fuel and water issues are such a large problem along with other issues in the marine industry when the fuel is left in tanks sitting for months.

hopefully this video makes that job easier. always remember to take photos to revert back to. good luck!

Thank you!

Thank you Trey

Thank you!! Thanks for the support

Thank you Steve

just yesterday i had the same problem on my yamaha 200 outboard 2004, it won’t stay running, only cranks. any suggestions?

I would try to manually pump gas with the primer bulb and try to start it. See if that keeps the engine running. (try to have a buddy continue pumping while you star the engine.) if that works it could be a failed low pressure pump. It can also be a bad fuel pump in the VST. However these engines really need clean fuel so I would start with that test and replace filters in the spin ons as well as the filter in the VST. Thats my approach

@@ReelTeaseFishing Thank you very much, I got new low pressure pumps because of the problem, but a more advanced friend of mine also suggested to manually start pump the engine and it seemed to work. again thank you for the response!

its hard to tell what the issue is, but definitely a lack of power. it can also be non engine related. such as water in the boat, improper trimming etc. I would check fuel filters first and move my way through the fuel system.

I had an HPDI and I would say your issue is fuel related with 95% confidence. You can easily check to see if the low pressure pumps are faulty by loosening the two bolts that hold them to the block. just loosen them enough to be able to free them from the block but not so loose that the bolts come out. then have someone pump the primer bulb. if fuel leaks from behind the low pressure pump, you have a bad pump and will need to replace. if it doesn't leak they are good to go. I would start with the easy things. if you are confident you have good fuel. (fresh and clean) then get some New spark plugs & change your spin on fuel filter as well as the fuel filter in the yellowish container under the cowling. Get back to us if that doesn't solve it.

@@ReelTeaseFishing thanks for the reply. I checked both low pressure pumps and they seem to be ok. I removed the hose from the top of the vst just before the barrel filter and started up the motor for a second and fuel came out so I’m assuming the vst is pumping fine. The only thing left to my knowledge is the high pressure pump and injectors. I’m going to try cleaning the vst tomorrow and see if I can clean the injectors. This is my first boat and I’m learning a lot by watching yours and others videos. I knew absolutely nothing a few weeks ago lol

Hey Dennis, You landed on the right video. Thank you for watching and reaching out. First things first, and may sound simple but have you tried leaving the throttle in neutral position and priming the bulb till it gets hard then turning the key to the on position. Allowing 5-10seconds to pass (this allows the fuel system to prime and fill all the rails, injectors etc. then turning the key to start the engine. Do this process maybe three times if it stutters and doesn’t start. If it doesn’t start but sounds like it wants to I’d look into your low pressure pumps. They are easy to check. Loosen one at a time (two bolts) but don’t completely take the bolts out just loosen enough to separate the pump from the block and have someone squeeze the bulb. If fuel drips or squirt out from behind the low pressure pump it has failed. Replace it. If all checks out I’d look into Your spark plugs look for good spark, perhaps a fouled plug on a cylinder. And a compression check can tell you a lot. The. I’d look into cleaning O2 sensor if your engine has one. I’d look into the temp sensor that may have failed and not letting the engine realize it is cold starting. (Temp sensor will, when engines cold, increase starting RPMs and decrease once engine hits operating temp) Lastly I’d get a link and sync performed by a mechanic. Good luck and please let us know if you solve it and what it was.

@@ReelTeaseFishing dude thanks a lot for that detailed reply, i'm actually totally floored that you would took the time to do that. I'll keep you posted.

@@ReelTeaseFishing hey carlos, ok here's the update. The very first 2 steps is what it took. pumped ball til hard, turn ignition to on to let fuel system pressurize, approx 30 secs. she sputtered first 2 and fired up and stayed running on number 3 time!!!! but here is a question Carlos, is that normal, and second, should we have to do that even when the engine is warm? we still will loosen low pressure pumps to check for leak, but from what your hearing what you think? And again, dude thank you so much for taking the time.

@@triathletechink69 ok that’s great news! I’m glad she’s running with just the start up procedure. These engines are some of the best engines Yamaha made for their 2 stroke era. Keeping that in mind, they are two strokes. They love fuel and don’t like cold starts. For the most part once the engines have warmed up they should crank right up unless they sat enough time to cool off and fuel pressures to drop etc. If you stick to that start up procedure it should crank right up. Let me know if that answered the question

Hey CJ if the engine is running when you prime the bulb then you have narrowed it down quite a bit. we know its fuel issue, and its because its starving of fuel. It could be a bad fuel bulb. It could be air getting into the fuel lines via a bad clamp or a dry rotted/cracked fuel line. also pin holes in the fuel line cause air issues too. Lastly the fuel pumps could also have failed. Let us know what you find. looks like you've checked off a few of the known issues as well.

Check the filter on your VST if you haven’t done so.

it definitely sounds like a fuel issue. I would start at the simplest things. spin on filter, then id check the primer bulb, then the inline filter under the cowling. anything that restricts fuel flow will cause a surging issue especially at higher RPMS. is your priming bulb going flat at higher rpms? does it ride better if you are at higher RPMS and you squeeze the priming bulb? I would check those things first. also any chance of water in your fuel?

Hey did you ever figure out your problem? Mines doing the same thing…. Awesome video by the way. I really appreciate you teaching your knowledge bro

Yes. These pumps are very accesible and only two bolts to remove them

It could be weak pumps, could be air leak in a fuel line, could be a non working choke. Weak primer bulb, clogged fuel filters. Hard to say really. But it’s definitely going to be a cold start/fuel issue

Oil Tank Harness also know as Lead Wire PN: 6R3-85721-30-00

to check the low pressure fuel pumps. loosen them and if they leak while you have the engine on (running) its the fuel pump.

I have this same issue, mine is a 98 Yamaha 115 2 stroke. I will look at the fuel pump next. I took the carbs off and they look good. When the motor is about to kill, I can keep it running by spraying carb cleaner in the carbs. Gotta be a fuel issue. Idles rough and doesn’t want to keep running at all.

Thank you for the support. I do not have a video on that but a fellow RU-vidr has a great breakdown on the VST. @BornAgainBoating

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Qtz-9_-_dTk.htmlsi=t-JxCt0ozMFq63MI

Try Crowley Marine They have a solid parts diagram and parts store online. I get all my parts from Marine Express which is local to me in South Florida

quickest way to diagnose is to loosen the two bolts but not remove it, just enough where you can pull the pump off the engine block and have the bolts still in the block. Then pump the fuel primer bulb. If gas starts leaking behind the fuel pumps, you have a bad fuel pump.

Sounds like you are on the right path. I would change the fuel filter in the yellowish bowl as well as the spin on fuel/water filter if you have one. Check clean and tighten all your grounds especially on the battery. 👍🏽

@@ReelTeaseFishing since my post we tested the spark while in gear and noticed it wasn't firing on all cylinders, my oil tank is low maybe that was forcing it to cut off when i went over waves I will fill it in the morning and see if that solves it. if not maybe bad coil well see! thanks for the videos they are great!

​@@jaredzeno keep in mind the HPDI is meant to drop cylinders at idle. This is normal, and supposedly makes them more fuel efficient. While at idle if you rev the engine it will start dropping more cylinder as the RPM's increase. its a fail safe for the engine. Low oil, water in the gas and overheating will put these engines in "limp mode" (this mode will drop cylinders too) Hope this info helps your diagnosis

Yes. It was cutting out while in gear and running. I pulled my spark plugs and they were loaded with carbon. I cleaned them and it ran much better I’ll put nee plugs in tomorrow.

is it holding at 3k rpm and not moving? it could be limp mode. Limp mode is enabled by three things. Low oil (or bad oil sensor in the reservoir both the tank or the one under cowling) Overheating & lastly water in the fuel. if you don't believe you are in limp mode, then I would suspect your fuel filters are clogged. try replacing the VST filter, your spin on filter and your water/fuel separator and see if you gain any RPMS. It wouldn't be a bad idea to put fresh plugs and run the boat on an auxiliary tank with fresh fuel (non ethanol preferred) while you diagnose. let us know if you find any new details.

The gasket comes separately

Part number for gasket is in video description

Ive noticed that the fuel in the bowl also doesn't stay full all the time. I would check simple things like fuel lines, fuel bulb. make sure they are clamped tight. hooking an HPDI to a computer via the diagnostic adapter would be the best bet.

@@ReelTeaseFishing Is software and cabling to connect to a computer available to public? Is it difficult to use/diagnose?

@@michaelphenix2557 you can buy the software and cable on eBay for about $100. its is called YDS (Yamaha Diagnostic Software ) then you will need a laptop to download the software and from there you can run the whole system diagnostic on your engine. fairly simple once you start messing around with the different options

@@ReelTeaseFishing thank you sir. Nice job

ok so a few things can cause this. air leaks are the number one culprit. make sure that all clamps on the fuel lines are tight. (don't use zip ties) #2 a bad primer bulb can cause the fuel to lose prime if its failing. #3 clogged fuel/water filter or the spin on filter may be lose and needs tightening #4 pick up tube in gas tank sometimes have a small mesh that gets clogged. #5 are you sure you aren't out of fuel, and getting a false reading of the gauge. #6 a small pin hole in your fuel line can be a PIA to find and will introduce air into your system. that's what I would be looking for. please let me know if you solve it, if not we can keep trying

@@ReelTeaseFishing Thanks for your help. It seemed we had everything running well. But now, after a short run, it seems after the engine is warmed up a bit, it quits running. I have been able to idle, only. any increase in fuel over 1100rpm and the engine quits running. Starts easily, but will not take fuel. It runs perfectly until it gets warmed up. I'm a shade tree mechanic and can't afford my local dealer. Thanks, again, for any assistance you can offer. Sam

@@kennaspade3607 I would check for spark in all cylinders. you may have a cylinder not firing. (bad coil, bad spark plug?) If they are all firing then I would check filters. on the engine itself I believe you have three filters. one in the front of the engine in a small spin on canister. another inside the VST, and another above the VST. Make sure those are all clean and new.

Please let me know what symptoms you are experiencing. is the primer bulb going flat when you run the engine? does the boat run better if you squeeze the primer bulb while running? Are you running Rec 90 (non ethanol fuel)

@@ReelTeaseFishing I have replaced the primer bulb. It is working fine. Engine quits after warming up. I am using 10% ethanol fuel.

Here’s what I would do. Id get an auxiliary(portable tank) 3-6gal tank with new gas lines and primer bulb. Id connect it with fresh gas to the outboard and run it. If it runs good you know the issue is from the fuel line back to the tank. If it runs the same. You can really focus in on the engine. There are way too many variables to say and this test really narrows it down. Plus you will have it for future diagnostics

@@ReelTeaseFishing Thank you so much for the recommendation, and FAST response.

@@alechamid235 no problem Alec, good luck and feel free to come back and ask more questions. Let us know how that test goes and we can go from there

High pressure pumps don’t look like these in the video

@@ReelTeaseFishing I figured it out. This Z150TXRA has the same two lp fuel pumps. Problem is finding them local to upstate NY

@@bsh21wash1 glad you got it figured out! 🤙🏽

I will try to get that video. Great suggestion