2001 Yamaha F115 four stroke won't idle - help!

hustler1961

Cadet
Joined
Mar 14, 2011
Messages
8
I have a 2001 F115 Yamaha four stroke with 850 hours on it that was idling rough.



Figured it was time for a little overdue maintenance.



I've done most of the work in the past on all my motors with very few issues.



Decided to change:



The timing belt and tensioner. Everything came off and went back in without a hitch. Located TDC on flywheel and lined up the arrows on the cam gears. Replaced belt. Adjusted tensioner. Smooth as butter.



Replaced old thermostat with a shiny new one. Smooth as butter.



Replaced the four fuel injectors. Everything came out easy-peasy and went back together again (checked the pressure in the fuel rail and had a bit over 40 psi - right in spec). Smooth as butter.



Removed the idle control valve and soaked it (completely submerged) for two days in Marvel Mystery Oil (after reading here that this method has worked for other guys). Replaced the old O ring and reinstalled the valve. Seemed smooth as butter.



Took the boat down to the water and initially it fired right up, but then it died out within moments. I was able to put the shifter in neutral and with about half throttle, was able to get the engine started, and and it ran smooth at 2000 rpm. However, every time I dropped it back down into idle/neutral, the engine would die out. Also wasn't able to get it started again in neutral.



WTF???



Could it be that soaking the idle control valve in the Marvel Mystery Oil screwed it up? I'm scratching my head thinking that - simply because it won't idle. BTW, I tried disconnecting the ICV while I had it running at high idle, but didn't notice a change - or when it was reconnected - just died out again.



Help!
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Last edited:

hustler1961

Cadet
Joined
Mar 14, 2011
Messages
8
Hummm,
I used a universal pulley holder with two pins that went down through the flywheel holes (to help hold the flywheel-and was a major pain in ass, when trying to pop the flywheel off the shaft with the flywheel puller).
After a long battle, the flywheel popped off, and underneath, I discovered that I had damaged one of the copper wires on the stator with the flywheel holder (must have went in too far).
Now I'm wondering if that may be the reason the engine won't idle?
Any feedback on that thought?
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Bottom line, you are going to have to replace the stator but not the cause of the idling. I wouldn't have submerged the IAC in anything and is probably the cause of the idle problem.
 

Charkra

Recruit
Joined
Jul 22, 2015
Messages
4
Is this injector or carburetor engine. If Carburetor, I had a similar issue with a carb engine and it ended up that there was dirt impeding the fuel flow out of those jets. It basically allowed me to idle(on what was 1 and a bit cylinders) with 2 cylinders totally blocked and the 4th partially. When I went to accelerate, it was spluttering, but eventually allowed me to go faster. Once above 2k rpm, it was no longer an issue. . Once I cleaned those out, it was like magic, all was good afterwards. Hope this helps.
 
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