idle speed

[burninman]

took my new to me monterey out yesterday for it's 1st test drive since i bought it. did well, but I think the idle was set high, it was running right around 2000 even after getting up to temp. I can't find anything in the manual about recommended idle speed, but it sure did make it thump into gear while it was running that fast. i dropped it to ~900 rpm and it sounded more normal to me. Is there a 'normal' idle range that i'm ignoring? it's a 4.3 if that makes a difference

 

[Bondo]

Re: idle speed

Ayuh,... It should be 650/ 700rpms at idle, in gear, in the water...

 

[burninman]

Re: idle speed

Ayuh,... It should be 650/ 700rpms at idle, in gear, in the water...

works for me. should i be concerned about why it might have been set that high? i didnt notice it at all running on muffs, but then again i never put it in gear to notice how hard it dropped in.

 

[Scag]

Re: idle speed

Always set the idle with the boat in the water. It will be different than when you do it on the muffs, but I wouldnt expect a 1000+rpm swing. I'd say put the boat in the water, set it at 650 and see if it stays there...then test that it will run on the muffs fine too.

 

[Don S]

Re: idle speed

should i be concerned about why it might have been set that high?

Absolutely you should be concerned, and you can do the preliminary adjustments on land, then the final adjustment (if needed) in the water.
DO NOT shift when it's idling at 2000 rpm, it will end up destroying your lower unit gears.
Many times engines that will not idle at the proper rpm are just adjusted to run at a higher rpm so the owners can use them.
You need to get a shop tach, (many time a digital on a timing light) to verify your tach is actually reading right.
Then disconnect the throttle cable from the carb linkage to make sure the cable isn't failing and what is causing the high idle.

 

[burninman]

Re: idle speed

Then disconnect the throttle cable from the carb linkage to make sure the cable isn't failing and what is causing the high idle.

Sounds like a plan. I have no doubt about how high it was idling. I did notice after i loosened the idle screw, i had to manually press on the throttle assembly to get it slow down. it was filthy, so i assumed it was just sticking and cleaned it with some carb cleaner and a paper towel. That could be a cable issue though