2.3L Cobra Tune-Up

[Mark22]

Hey guys,

I'm trying to get my `87 OMC Cobra 2.3L tuned up and in great running shape. I've hit a snag though, I can't get the engine idle set right. Today I hooked it up on the muffs and set the timing to 10degrees BTDC and hooked up a vacuum gauge. The gauge will read 15" Hg if the idle is set around 1000rpm. The manual says the idle should be 500-600. I am having trouble shifting out of gear and I think the problem is the higher idle. The ESA is working; the engine rpm "stumbles" when I press the switch. When I lowered the idle to 600rpm the vacuum gauge bounces between 10 and 15"Hg. If the idle is raised, then the gauge stabilizes around 15"Hg. Does anyone know how to properly adjust the idle mixture screws? It is a 2-BBL Rochester carb. Also the gauge goes up to 20 and then drops to 0 or 1 when the engine is revved up. The manual says it should go to 25 and then 2 when revved up. If anyone has scans of the OMC factory manual it would be a great help. All I have is the Clymer manual and it's kinda vague.

 

[mkast]

Re: 2.3L Cobra Tune-Up

You are going to have to get the engine idling first.
Timing rpm is usually achieved by putting the drive in gear.
In a perfect world, your vacuum gauge might reach 25 inches at idle with engine at operating temperature, most engines, in very good condition reach 18-22 inches, depending on engine rpm. All engines read 0-5 inches at WOT.

 

[Gary H NC]

Re: 2.3L Cobra Tune-Up

Its impossible to set the idle speed on the muffs.
It needs to be in the lake,throttle cable unhooked at the carb then set idle speed.Adjust the cable so it slides back into place on the carb linkage.

If you set it on the muffs it will not idle in the water...it will be to low.