[TigerWolf]

What I have done so far:
-on YDS the TPS adjustment is good (0.728V engine off, ignition ON)
-no error code.
-Static test of ISC is good. It also rattle when I turn engine off.
-Active test, 100% request increased RPM.
-During the 30min test, it seems the engine was idling smoother, request was around 65% during all the duration of the test, not sure how to interpret this.
-I did the pressure test as per the book on the low pressure pump and it is good.
-As suggested in another post by Rodbolt, I measured the temp of the ISC after running 5 cycle of stationary test with a IR gun it was 90F. BUT after I left the engine idling for 10min it reach 195F.
On YDS the ISC demand is between 62% and 65% when the engine is idling. here

[JohnnieMc]

Engine is a F115 2004 with 441h
Went through a huge service at 404h when I purchased it:
-New fuel filters
-New thermostat, old one was in bad shape
-4 new spark plug (removed one were all carbon fouled)
-New VST
-4 Injectors cleaned by a pro
-Reset the TPS to specs
-Cleaned the ISC

[T_X]

Some described similar issue due to TPS off specs, ISC sticking, bad shift Switch, damage low pressure pump diaphragm. more

[johnhurt112]

I have intermittent stalling when going back to neutral from cruising and sometime the engine seems to idle not as regular as usual, more like wrom wrom wrom wrom(hard to explain).
Engine work really well except this issue.

[imnichol]

So correct me if I'm wrong but to me it seems the ECU is sending an high request to the ISC. because of this the ISC ends up heating. more

[L29Ah]

Someone did post to NOT use WD-40, but a Silicon based lubricant!

[Renton777]

my 2001 yamaha F100 has same squealing noise?

[Hariposter]

Re: Yamaha F115 faint squeal or whistle

[Babylon]

I've got a 2006 F115 4 Stroke that did this and periodically does the same thing. Found out it was a rubber bushing on the drive shaft at the base of the powerhead that dries up a bit and starts to squeak. I now spray a little silicon lubricant onto the shaft and the problem goes away for several months. [links]

[ReganLahne2102]

Anyone else have any ideas? more

[xswqaazz]

Am not sure if this would apply to your motor but with my 2 stroke yam there is a bushing that the drive shaft goes through at the base of powerhead. They have been known to squeak or chirp. Easily accessed when the lower unit is pulled for inspection or repair work. Not sure if your setup is same but a possibility.

[theymos]

Mechanic performed pressure test (42 psi), at start up and with engines running, pressure test did not identify any issues. Mechanic replaced Main Relay because of heavy corrosion on pins. This did not solve the problem.

[ProPuke]

My 2004 port engines starts fine after priming the bulb, run at idle for 20 minutes, run engines for 20 to 50 min at 2000 to 5000 rpms, idle for 3 minutes or so to anchor. Anchore for an hour. Restart successfully, idle for 3-5 minutes, increase throttle to around 1500 rpms, engine dies. Engine also died recently after running at 4000 rpms for 60 minutes, then throttled back to 1500 rpms or so for about 5 minutes, engine died. Prime the bulb after each failure, and I am on my way again until the next failure.

[eedcxsww]

I purchased the boat in November of 2014, at which time I had the tank drained and vacumed, sending units were replaced with perfect seal, changed inline fuel filters, changed element filters, changed fuel water separator filter, changed oil and spark plugs - in December of 2014.

[teknohog]

[links]

[Quadrosmit]

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[rainerfox]

[williamsanderson71]

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[Regent]

[bbking2010]

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