Yamaha 200 HPDI fuel problems solved-HP fuel pump

If you’ve searched for a solution to HPDI fuel problems, this is it. I wanted to get this on here so that if anyone ever runs into this problem they know there is an easy solution. This is an all-in-one summary of how the fuel system works and what went wrong. I have never been into one of these motors before, but everything I did was extremely straightforwards. Nothing was more than some nuts and bolts. Total cost this way - $100, total cost at Yamaha’s solution - over $1800

Problem-
05’ Yamaha 200 HPDI started losing top end power. Would run fine wide open but slowly start slowing down (started 4200 then fell to 3400 RPM). Motor would run fine at certain throttle levels, but once you went above it would start bucking. It eventually got the point that I couldnt get on plane. It was odd because it idled fine and ran perfectly normal up to a certain RPM.

Diagnosis-

From reading about these motors, I found they are extremely sensitive to bad fuel. What I eventually realized this meant was any fuel. The fuel system flows in this order- Main tank - fuel/water seperator - primer bulb - on motor filter/seperator - (2) low pressure fuel pumps - VST filter and mid pressure pump - mid pressure inline canister filter - high pressure belt driven pump - fuel injectors. The crucial system that fails is small filters in the HP pump as well as injector filters (more on this later)

I took a few shot in the dark guesses at first because they would be simple, cheap fixes. I pulled apart the VST and cleaned the pick-up filter. It did have some sediment built up on it. Some seafoam and compressed air cleaned it up. Replaced mid-pressure inline filter. Still no fix. Next, I pulled the fuel rail to check filters on injectors. They looked pretty clean, so I didnt assume this to be a problems.

From here, I needed a Yamaha tech to test my HP fuel pump. The LP pump is an easy test. If you can squeeze the primer bulb and the motor picks back up, you have a bad pump. Easy fix. Always check to make

Thanks for the info. I ran into a similar situation with a Mercury recently, and resolved it with minimal cost and my labor.

Blackwaterkatz

I have an 01 200 HPDI.
Thank you very much for posting. Please post pics if you can.

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Luke 8:22-25

due to the EXTREME pressures, Yamaha doesnt want the pumps taken apart
as yamaha techs they dont even want us to work on them. take them off and send them to flag ship is what they tell us.
just an FYI
the little flexible metal tube that connects the HP pump to the fuel rail…
is about $600, so be careful when flexing it.
if the rest of the filters are replaced every 100 hours like they should be, and the racor kept clean, those filters arent usually a problem.
glad you were able to fix it without having to replace the pump

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Well done and good post

i just wanted to add that my 2001 HPDI z150tlrz engine had similar issues due to bad gas/filtration from the boat fuel tank. it probably would have cost me a WHOLE lot of money to let the dealer fix/repair the hi pressure pump. i was surprised how simple it was to take it apart. once you know how to do it , it can easily be done in an afternoon. it aggravates me that most sources say don’t touch it as well as offer very little info on taking it apart. i was surprised at the performance of the motor after the filter was cleaned. i only ran the motor for 30 minutes due to weather, but the difference was immediately noticeable. the best book i found on how to remove the pump was the yamaha Clymers manual. my local library had it online for free to review.

this is a link with some pict and more info
http://forums.iboats.com/showthread.php?t=338269&highlight=high+pressure+pump

http://forums.iboats.com/attachment.php?attachmentid=34071&d=1248667172

http://forums.iboats.com/attachment.php?attachmentid=34145&d=1248736138