Minor (?) Idle issue '89 4.3.

[Liquid_force]

Hello,
We have a new carburetor on our '89 4.3L.
It starts and runs well (even after sitting for 2 years doing a floor replacement project).
The problem is when the engine is warm the idle is quite high. Our tach has a glitch atm but my guess is 1000 rpm or more.
Needless to say, this effects the shift system as well.

I simply need to know how to get the idle down to a reasonable level.

 

[Scott Danforth]

adjust the idle when warm. when cold, it is common to have to use the throttle only button to keep the revs up.

 

[Redrig]

Either way you are going to need a reliable tach to set it as rpms level is important for proper shifting

 

[Lou C]

True get an accurate tach and use that to make your adjustments. Do you have a 2bbl or 4bbl, Rochester or Holley?

 

[Liquid_force]

It's a rochester 2 barrel.

I believe R2-2GE is the rochester ID.

It's a new carb. We've done leak tests and replaced the vacuum line. Just need it to idle slower. As it's a cobra with ESA i believe it's supposed to idle about as low as possible -- 650?

It's also "dieseling" when it's warm and turned off.

 

[Bondo]

Just need it to idle slower.

Ayuh,.... So back off the idle speed adjustment screw,......

If the throttle cable ain't pushin' hard enough, lengthen it til it causes the throttle to rest on the idle adjustment screw,....

 

[Liquid_force]

Ayuh,.... So back off the idle speed adjustment screw,......

If the throttle cable ain't pushin' hard enough, lengthen it til it causes the throttle to rest on the idle adjustment screw,....

Yeah, that was easy enough.

I also re-adjusted the transom cable and it seems to be shifting much better on muffs. Unfortunately I also found a tear in the u-joint bellows. So another week (or 2 or 3) off the water

 

[Lou C]

The best way to adjust the idle on these is to disconnect the throttle cable, and set the idle with an accurate tach with a hot engine. Then get someone who can spin the prop for you...OMC's way was to:
With the ENGINE OFF
get someone to spin the prop and shift into FWD gear, then shift half way back to Neutral. Now go to the throttle cable, hook it to the carb and adjust the trunnion to take all the play out of the cable.
You may need to re-adjust the idle speed slightly while on the water to make up for the back pressure of the water in the exhaust system...