2005 F90 Fuel Issue

[jlelectricllc]

I have a 2005 F90, fuel injected, 70hrs. I recnetly had water in gas, motor quit. I removed all the bad fuel, pull plugs and they looked good. Drained hose on fuel pump. Changed fuel filter in cup. Added a yamaha 10 micron fuel/water seperator. put 20 gallons of ethanol free back in. Runs great at idle. took out in the water. wont go over about 10mph, bogging down, and intermittent miss. I purchased some injection cleaner, will let it runs for a while tonight. If that doesnt work, is it work cleaning the injectors with carb cleaner? All the post I have read it seems to be an injector issue.

[boscoe99]

More likely than the injectors is the VST pump filter being clogged. An inspection of the filter is needed.

If the filter is cleaned and if you have rated fuel pressure at the injectors at all times but the motor still bogs down then yes I would agree with you that perhaps the injectors need to be cleaned. Hopefully it is just the VST filter.

[jlelectricllc]

Can the vst filter be cleaned or does it have to be replaced? Its not cheap. Im going to try some injector cleaner first.

[jlelectricllc]

I removed the vst, full of gelled fuel. looked like yogurt. Cleaned out VST tank and cleaned filter. Pulled injectors, let them soak for about 6 hrs in carb cleaner. Then sprayed them out with carb spray. Now the motor runs better than ever. Let it run at 2500 RPMs for about 30 minutes to get the injector cleaner flowing. Ran awesome. Thanks for the input and previous posts, saved plenty of $$$.

[kajikikai]

Where is the VST filter? Is it the strainer attached to the bottom of the fuel pump?

[jumpfiend]

Hi guys,

New to the site, have a 2010 F90TLR that sat for awhile and is having similar issues, I suspect I need to pull/clean the VST filter.

I'm trying to find a service manual for my engine, are there any available for free online?

Cheers!

Steve

[99yam40]

buy from Yamaha.
Not good to post on others old threads,
start you own to ask questions of your own

[FLCoyote]

F90 Fuel issue

I also have a 2005 F90. About three years ago my fuel lines disintegrated and clogged the VST and probably left a lot of small debris in the tank. I had to have all of the fuel lines and the VST filter replaced. My dealer said that Yamaha did not go to ethanol resistant fuel lines until 2006. The VST/fuel line issue comes up fairly often on this forum. At the time my fuel lines came apart my dealer said that I was the 5th or 6th F90 he had repaired with this problem. I've also had wiring harness problems and had to replace the entire harness once and had it repaired once. Yamaha does not recommend repair. I understand that the wiring harness problem also happens frequently on the F90. So far the wiring harness, fuel lines and VST have cost me $2700. By the way Yamaha only warrants replacement electrical parts for 30 days. I found that out when my replacement wiring harness broke down in less than 12 months and Yamaha didn't want to know.

FLCoyote