Yamaha Fuel Problems

red968

Recruit
Joined
Mar 18, 2017
Messages
4
Hey Guys,

I've been reading posts and trying to diagnose my fuel issues. I have an 08 F90 TXR on a 22' Sundance. Last June we took it out 8 miles in the gulf trolling. It seemed to run ok at first but hours later progressively lost power coming in until it would barely plane off. There was a good chop so I adjusted the trim back in forth thinking it was a trim problem. At the ramp the trim motor bit the dust and would just click the relay. In November I replaced the trim motor, changed the engine oil and filter, replaced the small fuel filter on the back of he motor. I changed the big fuel filter on the transom. Siphoned out the old fuel from the tank and replaced it with a couple of gallons of Rec fuel unleaded with no ethanol with a dab of Stabilize. I pulled fresh fuel through to the bulb and ran the motor on a hose for 5 minuets or so. Last weekend, I added 10 gals of fresh Rec Unleaded and took the boat out on the lake. Cranked right up at the ramp. I idled out and tried to accelerate, no dice. I starts to run erratic and acts starved for fuel and won't accelerate past idle speed. We sat and fished out from the ramp. I thought it may just be some bad fuel in there that needed to work out but it never did. I was able to idle it around and get it back on the trailer.
Now I am reading about cleaning the fuel filters, checking VST pump, and possibly checking other filters. I would like to fix it myself if possible but not sure where the most likely area is to start my efforts. I'm reluctant about going to my local boat repair place. They wanted about 8 to 900 to replace the trim motor. I got it on amazon for 175 and swapped it in 35 minutes after watching a u-tube video. Any advice would be appreciated. I have a 18 sec video from the lake. Video available via email. :)
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Welcome aboard.

Why limit the help by sending the video via email? I'm not giving you my email address to see your vid and very few will. Post the video here or upload it to Youtube and give the link.
 

red968

Recruit
Joined
Mar 18, 2017
Messages
4
I've got the video public now. Please forgive my mixup. I drained the VST this afternoon and the fuel that came out looked good. I did not see any water or sediment. Pulling the motor parts off to change the VST filter looks like a real pain. I don't know why yamaha burred it like they did.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
they did it to try and keep people not experienced at working on these motors from playing with them.

It is not that bad once you get your mind around it.
Most important things in life are not simple
 

red968

Recruit
Joined
Mar 18, 2017
Messages
4
I fixed it! Checked the fuel pressure and I was good so I sent the injectors off for cleaning. The injector cleaning guy said to go ahead and clean the VST tank and filter or the cleaned injectors would most likely clog back up in a short time. I ask him about fuel additives for future protection. He said they cause corrosion and does not use them. Said that maintaining fresh fuel with or with out ethanol seems to work best.
I pulled the VST tank, no big deal, it looked more complicated than it actually is. I changed the filter and cleaned the tank. Had to wire brush the high pressure fuel pump housing because it was covered in loose powdery corrosion!! Wow, those fancy external filters aren't gonna keep that crap out of the injectors! The VST filter screen is the only defense. Thanks Yamaha for brilliant engineering. Maybe Honda or Suzuki do it better, I will find out on my next one.
Anyway, put it back together, new spark plugs too.. Out on the lake it runs like a banshee.
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