Idle speed for 2001 F115

[theoldwizard1]

My 2001 F115 seems to idling lower than what I remember, about 800 RPM. What should it be ? I also is stalling after throttling back quickly. I'm guess the IAC is sticking.

[fairdeal]

I suspect 750 +/- 50 is the spec
so 700-800 is right

but stalling after throttling back is what the ISC is supposed to prevent

so maybe its "sticking"

but I suppose the ECU can't activate the ISC if it doesn't know the throttle has been closed - so does the TPS factor in there?

[theoldwizard1]

but I suppose the ECU can't activate the ISC if it doesn't know the throttle has been closed - so does the TPS factor in there?

I am sure it does, but my gut say 800 is a bit low.

[RayBersch]

Trust your owner's manual not your gut. It says:

"Idling speed (in neutral): 750 ±50 r/min"

If you are also getting a stumble upon acceleration, think TPS.

[pstephens46]

800 is low? Fairdeal just told you the specs.
Yamaha specs.

I prefer 650rpm on my F150. Less wear and tear on the lower unit when shifting.

[TownsendsFJR1300]

800 is low? Fairdeal just told you the specs.
Yamaha specs.

I prefer 650rpm on my F150. Less wear and tear on the lower unit when shifting.

+1 ^^ and Fairdeals post.

My F150 is the same spec. Its pretty much at 700, NEVER 800 (un-less cold), occasionally 600 RPM's.

The "stalling issue" (same as yours, when it was new) was repaired under warranty eventually.

[dray0151]

+1 ^^ and Fairdeals post.

My F150 is the same spec. Its pretty much at 700, NEVER 800 (un-less cold), occasionally 600 RPM's.

The "stalling issue" (same as yours, when it was new) was repaired under warranty eventually.

Please explain what the warranty fix was for the OP. Was this Rodbolt famous lync/sync and fooling the ECM?

[TownsendsFJR1300]

+1 ^^ and Fairdeals post.

My F150 is the same spec. Its pretty much at 700, NEVER 800 (un-less cold), occasionally 600 RPM's.

The "stalling issue" (same as yours, when it was new) was repaired under warranty eventually.

Please explain what the warranty fix was for the OP. Was this Rodbolt famous lync/sync and fooling the ECM?

I didn't post the "fix" as the shop was in-competent.

They REPLACED the ENTIRE THROTTLE BODY assembly (which I know wasn't the issue).

I shortly thereafter had a low idle again and literally watched a tech (with one screw driver) tune a NASTY VIBRATION into the engine. Of course I was told that was "normal" (although it idled smooth before that, just low).

Brought the boat to another shop with a MT who was able to bring the idle up and smoothed out the engine again (using the lap top, etc).

I don't know what he did but it was BEFORE RB posted his "fix" (which I have saved).

That was least 6 years ago, haven't touched it since.


.

[pstephens46]

There is a document with all the details of the F150 adjustment.
Actually, Scott sent it to me awhile back.

Little more involved than a screw, unfortunately.

[theoldwizard1]

The IAC was sticking in the closed position. I soaked it in a bucket of carb cleaner for 24 hours and the gave it a couple of shots of brake cleaner right at the pintle.

Works perfect now. The dashboard tach says the "correct" idle RpM is about 1000.

[pstephens46]

The IAC was sticking in the closed position. I soaked it in a bucket of carb cleaner for 24 hours and the gave it a couple of shots of brake cleaner right at the pintle.

Works perfect now. The dashboard tach says the "correct" idle RpM is about 1000.

1000 more than likely will stress your lower unit when shifting.
How's does your tach know the correct idle rpm?
Run any way you choose. Lower units are pricey.

[99yam40]

I had no idea the tach knew what the correct RPM should be

[pstephens46]

Reminds me of the six shorted injectors....

[TownsendsFJR1300]

The IAC was sticking in the closed position. I soaked it in a bucket of carb cleaner for 24 hours and the gave it a couple of shots of brake cleaner right at the pintle.

Works perfect now. The dashboard tach says the "correct" idle RpM is about 1000.

1000 is still way too high.

Obviously working better, but you'll destroy the LU shifting that high..

I see a new (or new to you) ISC valve in your future or a lower unit...

[rodbolt17]

it just needs an alternator.