Intermittent Stalling on Idle When Hot

Wondering if anyone can point me in the right direction. I have searched around and can't find a similar problem to this.

I have a 5.7 Mercruiser, with a 2 Barrel Carb TKS, from 2005-06. I have no problem starting, cruising, accelerating etc. But when the engine gets hot, after an hour + of use, when I take it back to idle I will see the RPMs start to go below idle range of 700 and then eventually the engine will cut out 5 secs or so. I have no problem restarting it, but not great when coming into dock.

I thought it was the ignition coil, so have replaced that, but didn't fix it. Carb is recently rebuilt, by previous owner. I sprayed Seafoam in the carb and added to the fuel. Fuel filter doesn't have any water in it. I have tuned the idle mixture by ear, trying to find a place to attach the vacuum gauge (can't find where though?).

My only thinking is this:
1) change spark plugs
2) change water fuel separator filter
3) adjust idle mixture screw (just one on this carb), might be running too rich when hot causing a stall?
4) go into the rest of the ignition electrical system (this feels like chasing the unknown)

Anyone experienced similar to this, or ideas on a fix?

You might have a 'slow flooding' issue that, when you adjust the idle mixture, the motor will idle fine. But after a run, when you throttle down,, the carb is now too lean until it "catches" (so to speak) by flooding. I've seen that happen before.

If I am correct, if you wait long enough at idle this situation will correct itself.

Jeff

fastjeff said:

You might have a 'slow flooding' issue that, when you adjust the idle mixture, the motor will idle fine. But after a run, when you throttle down,, the carb is now too lean until it "catches" (so to speak) by flooding. I've seen that happen before.

If I am correct, if you wait long enough at idle this situation will correct itself.

Jeff

Click to expand...

Would this not cause starting issues if there was flooding? I can start immediately after a stall.