Idle adjustment

[mainiak1]

I have 1998 21i with 350 mag mpi Mercruiser #OL008538 is there an idle adjustment ? Mine when warm idles at 500 rpm.

Thank you,
mainiak1

[lee]

The idle is controled by the ECM so there is not much adjustment.

[jsz]

I recently thought about adjusting the throttle too. It would stall about every other time I slowed down to pick up a skier unless I caught it in time and gave it a little gas. I changed the fuel filter but that didn't seem to help. Only other quik fix I can think off is the spark plugs if there's no way to up the throttle. Anyone else have any ideas?

BY the way LEE... are you saying it can not be adjusted at all because of the ECM or can it be adjusted a little???

[lee]

You can tighten the throttle cable and make it rev up a little that way.

[jsz]

Well another year is gone and I still have the same problem (stalling). I thought it might go away but since it hasn't, I'm ready to ask LEE or anyone else how to tighten the throttle cable?

The boat runs great at all other RPM's and only stalls at very low RPM's.

[FIC]

There is normally a sealed base idle setting on the throtlle body which requires a specified procedure to adjust. Next is the idle control motor some times needs to be removed and cleaned because they get dirty and stick. If I can answer any other questions for you call me at 1 888 517 3178. Dom@ Fortes Inboard Connection.

[chpthril]

the idle control motor some times needs to be removed and cleaned because they get dirty and stick
I 2ND THAT. ALSO 'CRUD' CAN BUILD UP AROUND THE THROTTLE PLATES AND AFFECTS THE 'MINIMUM AIR RATE' (BASE IDLE).

[jsz]

Originally posted by FIC
There is normally a sealed base idle setting on the throtlle body which requires a specified procedure to adjust. .

Is this the same thing that lee was talking about earlier - "The idle is controled by the ECM so there is not much adjustment."???

[jsz]

Originally posted by FIC
Next is the idle control motor some times needs to be removed and cleaned because they get dirty and stick.

I'm not a mechanic but I like to do small things myself. Is this a DIY project (no specialty tools)?

[lee]

The IAC, Idle Air Control is a do it your self. Two bolts and a plug in wire. It is located by the air intake under the plastic breather cover.

[jsz]

Thanks Lee, I'll give it a shot.

[jsz]

Originally posted by lee
The IAC, Idle Air Control is a do it your self. Two bolts and a plug in wire. It is located by the air intake under the plastic breather cover.

Ok Lee, you were pretty specific and I still can't tell where the IAC is. Can you point it out for me? Thanks. I'm going to try and post a pic.

[lee]

From the artist!:cool:

[jsz]

Thanks Lee. It's a good thing I asked. I was looking somewhere else.

[jsz]

I gave it a look yesterday and noticed the whole thing you circled in red has a thick black coating on it, even the 2 screws. It looks like it is not supposed to come apart.

[FIC]

The coating is just a pretective for corrosion it is made to come apart, that valve is a plunger that is electronically controlled to move in and out to regulate how much air bypasses the throttle to raise or lower your idle, it gets gumed up and will stick .

[jsz]

I removed the IAC and sprayed Throttle body cleaner in it several times. I even filled it up, covered the holes and shook it up. The liquid came out very dirty at first but I kept doing it until it came out clean.

I also sprayed the cleaner on a rag and wiped the air intake butterfly and everything else I could reach. A fair amount of build-up was there also.

Lastly I hosed the spark arrestor off. That didn't do much so I sprayed it with the cleaner and again much build-up came off.

Now the good news. IT WORKED. :ro: I ran the boat 4 days in a row and it didn't stall once. Thanks to all of you who helped with this.

Since this thread is titled "Idle adjustment", I will copy this post to a new thread. sorry for getting:ot:

[whitlock87]

Thats good to know
Thanks Lee