4.3 Inconsistent Idle

[Jmunk]

2003 Sea Ray 182
Engine serial # 0M369570

This boat is newer to me and recently noticed the idle was a tad high at around 850rpm. I turned it down on the idle speed screw on the carb to 650rpm per the factory tach.

Boat runs great and with the idle speed now around 650rpm. After coming off a run for a few minutes or more the idle is around 900-1000rpm in neutral. Didn't know if this is normal and how the carb engines are or if it should return back to 650rpm after coming off plane and taken out gear.

When I come off plane and its idling high if I turn it off and then turn it back on it's lower around 650-700rpm.

The idle screw is resting on the choke cam when placed into neutral with pressure for forcing it closed.

 

[Docksidemarineservices]

If you let it run does it come back down to idle on its own after a minute or so?

 

[Jmunk]

If I let it idle a minute it seems to come down 50-100rpm then I shut it off. Never waited much longer then a min or two to see what happens before I shut it off or put back into gear.

 

[Docksidemarineservices]

On a wetted intake engine it is not uncommon for the engine rpms to hang after running at WOT.

 

[Jmunk]

Thanks for the replys. I had it out yesterday and noticed that after coming off plane and going into neutral it 1st idles at 900, then after a minute or so goes down to around 800rpm. If I turn it off and start back up right away it back around 650rpm.

I can live with it just don't want to hurt the outdrive shifting in and out of gear at 800rpm.

 

[kghost]

Back the idle down some and see if that helps. Say 600 rpms.

 

[sandkicker]

Re: "the idle screw is resting on the choke cam when placed into neutral with pressure for forcing it closed."

Not clear... You need to force it against cam, or throttle cable does???

When adjusting idle, disconnect throttle cable and adjust idle. Readjust throttle linkage to make sure it reconnects with carb without disturbing idle adjustment. You want a small amount of "bias" on that linkage to make sure throttle cable keeps carb throttle arm up against the idle screw when in neutral. It linkage worn, may need to fiddle a bit. And a Chris said, sometimes idle speed is high and drops, sometimes you need to very slightly "blip" the throttle.

 

[Jmunk]

Sandkicker - there is light pressure seating the idle screw against the stop.

On this setup the idle screw is on the throttle arm that pivots and open the throttle plate. The screw it's comes to rest on the choke cam.

I will turn down the idle speed a hair more and report back. Perhaps the factory tach is off some, at 650 it idles very smooth. My timing light unfortunately does not have a rpm read out like some to very the factory tach.