Yamaha F150 too much presure from the mechanical fuel pump!

[the sand flea]

I've been fighting ethanol issues for some time now. I've replaced the electric pump, filters, fuel lines under the cover, the vst pressure regulator and now I'm perplexed! The engine idles great in the driveway but after a short run it will run rough, dump fuel overboard and eventually flood itself at idle.

I test the PSI from the mechanical pump and get up to 12 PSI. How can this happen and what is the remedy? I prefer not to just change out the pumps at over $200.00 each and really fix the issue.

 

[ondarvr]

What are the Ethanol issues you've been fighting?

What year is the motor?

Why were all those components replaced?

 

[the sand flea]

What are the Ethanol issues you've been fighting?

What year is the motor?

Why were all those components replaced?

Ohh it is a multi beverage saga!!

The motor is 2007 and now has about 200 hours on it. Ethanol has caused me to replace the electric fuel pump (it was covered in a rust like material), the fuel tank (it may have been compromised but the original pickup was dissolved and its replacement lasted less than an year), all of the engine hoses (had pin holes in the curve from the injector rail back towards the VST and was almost eaten through), the needle valve and seat (the seat had a mild indentation and was replaced for cause), the pressure regulator (if the electric pump looked like it did then the inside of this had to be as bad).

The only thing I'm left with is the original float, which I should have dumped while I was in there.

 

[Capt Ken]

You have a different problem than ethanol. Yamaha fuel systems will withstand up to 10% ethanol with no damage.

 

[the sand flea]

You have a different problem than ethanol. Yamaha fuel systems will withstand up to 10% ethanol with no damage.

The engine can handle it but some of the internal parts were not alcohol compliant and have suffered from it.

 

[GA_Boater]

The engine can handle it but some of the internal parts were not alcohol compliant and have suffered from it.

I'm sorry, but internal engine parts can't handle ethanol in an engine designed for E10? Even 100% alcohol won't rot a fuel tank or pickup in 12 months.

You have something else going on. Possibly an electrical bonding problem.

 

[ondarvr]

Since I've run E-10 in everything for the last 25 years with none of those issues, plus I have many friends, many of them guides, that run E-10 in their Yamahas and have for more than a decade, I can tell you that what you're experiencing is not normal alcohol poisoning. The motor sounds like it injested a large amount of water that was left in the system, or it was there for a long period of time while it was being used, possibly someone tried adding a large amount of fuel dryer to remove the water, which is typically just more alcohol, and that created probelms. Is this a saltwater motor?