Mercruiser Low Speed Idle Adjustment

[HellRaZoR004]

I have a 1999 Mercruiser 5.7L EFI engine that runs great but I think the low speed idle is a little high (800rpm).

I would like to dial down it down to what I've read on the internet should be around 650, but would rather do it myself and learn something along the way than having the shop do it for me.

That being said, can anyone give me some help on how to do this? I do not have a service manual for the engine (Serial Number: 0L095724).

Thanks,
Rob

 

[Bondo]

Re: Mercruiser Low Speed Idle Adjustment

I have a 1999 Mercruiser 5.7L EFI engine that runs great but I think the low speed idle is a little high (800rpm).

I would like to dial down it down to what I've read on the internet should be around 650, but would rather do it myself and learn something along the way than having the shop do it for me.

That being said, can anyone give me some help on how to do this? I do not have a service manual for the engine (Serial Number: 0L095724).

Thanks,
Rob

Ayuh,... Welcome Aboard,... It's done with a 'puter,... it's Not a mechanical adjustment...

 

[Don S]

Re: Mercruiser Low Speed Idle Adjustment

There is no idle speed adjustment, that is done by the ECM and the IAC to control it. What can happen is the throttle cable wears and does not allow the linkage to go back to idle. Disconnect the throttle cable from the throttle body and see if the engine will idle down.

 

[HellRaZoR004]

Re: Mercruiser Low Speed Idle Adjustment

Thank you! These engines are getting harder and harder to work on yourself.

I'll go ahead and disconnect the throttle cable and see what happens. If it does go down what are my options?

 

[Don S]

Re: Mercruiser Low Speed Idle Adjustment

If it does go down what are my options?

Adjust the cable so it lightly pushes the linkage to the idle position.

 

[HellRaZoR004]

Re: Mercruiser Low Speed Idle Adjustment

Adjust the cable so it lightly pushes the linkage to the idle position.

Thanks, I'll give it a try and post an update.