F115 difficulty starting when warm

[greenfshrmn]

Hi folks, this motor is a 2004 with 100 hours on a 17ft Lund. Been flawless since new but suddenly has difficulties starting. It cranks fine, just refuses to fire, as if the emergency lanyard has been pulled. Not sure if it's a coincidence, but it starts after sitting for few minutes and giving the fuel ball a couple of pumps. Once it starts, it idles and runs perfectly. For whatever reason, I cannot get this to act up when connected to a water supply in the driveway.

After reading a few posts, I have checked to hear the ISC motor rattling when the motor is turned off. Has new plugs, old ones looked good, and fuel filter. The last time I changed the oil, I noticed that the oil level was way too high, I wish I had thought to check for gas in the oil, but at that time the motor was running well. Fuel pump diaphragm perhaps? Anyone have any suggestions or experienced this problem before? Thanks for any help you can give.

[boats.net]

Load test battery, check voltage at engine is 10 volts or more while cranking engine over.

[angjackson]

115 4 stroke yamaha 2003

I have been having same problem. Starts fine then will not start for a while has taken as long as 20 minutes to start. have ask a lot of folks about problem. Some thing it could be nuetral switch on motor control. Mean while I ran mine very hot, putted in late night with no water pumping. I can get it started but runs very rough. I have changed water pump,oil,pulgs,injectors,did compression test, spark test(seemed weak)and pulled intake manafold, cleaned screen filter in high pressure fuel pump. I had bad carbon build up in intake head valve area, cleaned everything as well as I could. Trying to decide to scrape or keep on trying