Yamaha F115 Fuel problem

Pet982

Cadet
Joined
Apr 9, 2013
Messages
11
We have a F115 EFI with about 800hrs on it. On Saturday it went in for the first time this season, it cranked slow and took a little bit to fire off but it did. It ran beautifully, full power and idling.

I went to take it out Monday and it did not start, cranked fine but would not fire. Today I tested spark (yes) and changed the battery. I did get it start but only after cranking it for a while (many cycles). After I got it running it ran beautifully (plenty of speed, no hesitation, perfect idle). Let it sit for a few hrs and it will not start easily. I am leaning towards fuel and not spark.

When I push the schrader valve on test port on the fuel rail I get a spray of gas, then if I crank it and push again I get a spray again so fuel is getting to the rail.


What else should I look at? restricted VST filter?
 

charleso

Petty Officer 2nd Class
Joined
Nov 13, 2006
Messages
179
Check your actual fuel pressure. Not sure what spec is, but you can probably find it online. If pressure is low, then it may well be VST. If pressure is ok, then check to make sure injectors are getting voltage and are delivering fuel.
 

charleso

Petty Officer 2nd Class
Joined
Nov 13, 2006
Messages
179
One other thing. Double check and make sure fuel has not got water in it for some reason.
 

Pet982

Cadet
Joined
Apr 9, 2013
Messages
11
Today I went to take it out of the water to work on it and it would not start again (almost killed the battery). I shot some starting fluid into the air intake and she fired right off and ran beautifully. Immediately I got a high temp alarm, so I think i found the problem, a bad temp sensor telling the computer its warm/overheated so it's firing too lean for a cold start.
 

charleso

Petty Officer 2nd Class
Joined
Nov 13, 2006
Messages
179
Isn't all the electronic devices on engines wonderful? Be careful with that starting fluid, you can mess things up big time with it.
 
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