Idle setting 5.7

[Mamier]

My 5.7 MerCruiser has been idling at 800rpm (even in gear) and now its jumped to 1000rpm at idle and in gear. Can anyone tell me what its suppose to idle at? I've ordered my manual.

 

[Don S]

Re: Idle setting 5.7

650-700 in neutral. Assuming you have a mid 90's engine, you don't say.<br />You may have to adjust the throttle cable a bit in order to get a "SLIGHT" amount of preload on the carb linkage at idle.

 

[Mamier]

Re: Idle setting 5.7

Thanks Don. 1985 MerCruiser 5.7 260hp. The manual should come on Monday. Can you point me in the direction of where to do the adjustment?

 

[Mamier]

Re: Idle setting 5.7

Don, got the manual today. Planning on reading up on all I can this weekend. But something baffels me. The engine runs great. When I start it, she starts right up (first key turn). Idle at that point is right at 700rpm. <br /><br />Then I take her out for a run..no WOT, just 2800-3500. Get back to the dock and she's idling at 1000rpm (in neutral). If i let it sit for an hour and re-start, back to 700rpm. <br /><br />Thoughts?

 

[Don S]

Re: Idle setting 5.7

You're just going to have to start troubleshooting. <br />Vacuum gauge tests on engine vacuum, compression tests, fuel pump pressure test and vacuum tests on the system from tank to fuel pump, ignition timing and advance tests, carb adjustments, check plug wires, tuneup...... etc.<br />You are just going to have to eliminate things systematically till you locate the problem.