F115 testing high pressure fuel pump

[Yamauser]

My Yamaha F115 is currently in the shop. It would idle but would not power up. My mechanic is just starting into it and says it is showing no pressure in the high pressure fuel pump. I can't afford to pay for a pump I may not need and was wondering if that is the best way to check the pump. I was also concerned about what would be a fair cost of replacing the pump. I also broke rodbolt's cardinal rule and did not check the mechanics Yamaha certificatioin.

 

[capt sam]

Re: F115 testing high pressure fuel pump

I want to say they are around $350 just for the pump. Alot of times you can get a lot of crap in there and in the injectors and that will cause a restriction, see if he will try and clean everything out first.

 

[kissmywake]

Re: F115 testing high pressure fuel pump

If you had NO pressure, it would not run at all. He is probably "dead heading" it at the vapor seperator tank with a ford type automotive gauge. This can give you faulty results, I have been there. I have never seen a high pressure pump causing your symptoms, which doesn't mean it can't happen, but it is unlikely. Ask him if he has hooked it up to the YDIS system (computer interface). If he has not, or does not have the capability go somewhere else.

If it truly is a high pressure fuel pump, expect to pay around $400-550 parts and labor.

 

[Yamauser]

Re: F115 testing high pressure fuel pump

Thanks for the responses, Sam and Wake. Now I have a couple good questions I can ask.

 

[rodbolt]

Re: F115 testing high pressure fuel pump

normally if the pump runs at all its good.
another quick test is to pinch of the rail return line and see if the pressure comes up.
could be a bad regulator or as simple as a clogged VST pump inlet filter.
takes about 1.5 hours to clean the VST filter.
the later F115 motors, and thats 2 rules ya broke (no model number), also have a 10 micron inline filter just before the VST that can clog as well.
but if the pump actually runs most likly its not the cause.

 

[Yamauser]

Re: F115 testing high pressure fuel pump

I talked to the mechanic, he said by no pressure, he meant it was completely dead. It doesn't run even when hooked directly to the battery. A new pump for a F115TXRA is about $420.

 

[rodbolt]

Re: F115 testing high pressure fuel pump

you or your mechanic isnt being quite truthful.
on an EFI 4 stroke if it runs AT ALL it means the high pressure pump is working some, not dead.
when was the last time it ran ok?

 

[Yamauser]

Re: F115 testing high pressure fuel pump

The last time it ran was last fall. I idled out of the no wake zone but it would not power up. I idled back to the ramp and loaded it up. At home I was able to start it up and flush it out both with earmuffs and the flush out attachment at idle speed. Thinking it might be a gas problem, I changed the in-line 10 micron filter. Removed the on-board filter and pumped gas with the bulb making sure the new canister was fully primed and that any old gas between the filter and motor was purged. I replaced the on-board filter and primed that. When I tried to start to motor it would not start. Since it was already flushed, I went ahead and winterized it. So, to sum up, it did run at idle the last time I tried to use it, but it would not run at all when I took it the mechanic.