4.3GL Idle Issue (Am I missing a spring)

[barthel]

Evening All,

In an attempt to solve a dieseling issue, I tried to adjust the idle on my boat tonight. Here's what I noticed;

Once the engine was warm, I adjusted the idle screw, there was no change in engine speed. Turned back the other way ( few turns), same thing, no change. I grabbed the linkage to exercise it and found that it apparently wasn't seating all the way against the idle screw. When I seated it, the idle pulled down.

So, I got it adjusted to about where I want it (700 to 750 in gear), but if I move the throttle then reset it to neutral or idle, it idles about 1000 to 1100. If I gently nudge the linkage, it goes back down to 700/750. The throttle linkage to the binnacle seems to be adjusted in about as far as it can, so I've got nowhere to go there.

After surveying it, it looks (to me anyway) like I may be missing a return spring. Attached is a pic of the linkage, can someone please confirm or deny my thinking?

Much Obliged.

IMG_2744.jpg

EDIT: This is a 2bbl Holley on a 2000 4.3GLPEFS with an SX-M sterndrive.

[Don S]

Disconnect the throttle cable, then adjust the idle screw. Then adjust the throttle cable end so it puts light pressure to idle on the carb linkage.

[barthel]

Is there another way to adjust the throttle cable? I thought about doing that Don, the turnbuckle would need to be screwed in 2 or 3 turns, but the throttle cable end seems to be screwed in as far as it will go. Would I try to adjust it from the binnacle?

[Don S]

Check to make sure the cable is hooked up correctly.

7797282 EF Installation Manual 40.pdf 7797282 EF Installation Manual 41.pdf

[barthel]

10-4, I'll check it tomorrow and report back.

Thanks Don.

[barthel]

UPDATE:

Don, the diagrams for the cable hook up were invaluable!

The trunnion was mounted in the incorrect location, 4.3 for NON VP engines. I moved it to the proper location, backed the linkage out and now have the idle adjusted at 750RPM's dead on. When I pull the binnacle back to neutral, engine idles at 750!

Thanks a TON Don!

[Don S]

Sure would be nice if all problems were that easy to fix. Glad to hear it worked for you.

[barthel]

UPDATE II:

Well, had my boat in the water for the first time since I did the idle adjustments. It started and idled just fine until I put it in gear. Once I put it in gear the idle dropped to about 450RPM's. Put it back in neutral and the idle went up to 750, back into gear, back down to 450.

So, I pulled the engine hump, got a screwdriver and adjusted the idle with it in gear. Got it back up to about 700/750 and it ran good, but when I put it back into neutral it went up to 950/1000. The dieseling issue returned, although not as bad as before.

So I'm sort of wondering what now?

[skydiveD30571]

I was fighting the same thing on a 5.0GL. I had a mechanic listen to it and he immediately said it was idling lean. I haven't done a "proper" carb adjustment, but he backed the mixture off (more rich) a couple turns and now I have a 50-100rpm drop when put into gear. It used to drop 250-300rpm. I realize it can be a million things, but it wouldn't hurt to check that out.

He said a lean running engine becomes more apparent when a load is placed on it. Who knows, but it worked for me.

[Don S]

300 rpm is way too much rpm drop. When was the last tuneup? Have you done a compression check? Timing check? Have you tried adjusting the idle mixture screws?

[barthel]

Don,

Just got done doing a tune on it after I bought it (about a month ago) which was plugs, cap, rotor, wires, impeller, t-stat, oil and both filters (fuel and oil). Don't know about timing, compression (although it seems good, meaning good exhaust tone, fires right up and runs strong through the power band), F/A mixture or timing. Is that where I need to head next?

Old plugs looked OK, they didn't look like it had been burning lean.