I have had numerous posts while rebuilding a 2556 1988 5.7 OMC Cobra. All of last year we could not get this engine to run correctly.
Between last season and this season I had the quadrajet rebuilt, bought a new 1/4" carb gasket. Installed new risers, had the intake boiled out, had the heads rebuilt, new exhaust manifolds, installed a new Carter fuel pump, changed the one way hose valve for the gas tank, removed the gas tank pickup to make sure it was clean, changed the gas tank hoses and vent, changed, New spark plugs, wires were changed last year, cap and rotor were clean. I installed a brand new electronic shift interrupter switch. I also installed a new electronic ignition which was specifically made for electronic and or old fashioned points ignitions. All of last year it would stall at 2500 rpms and above. This year I pulled the distributor. Was told by a mechanic no wobble looked ok. Reset timing to 3degrees. Now I can get to 3200 - it wont stall however it will not get up to 4200 where it should be WOT. After all of this it still stalls when I lower the idle enough to try to shift and the idle is lumpy. Therefore I decided enough and removed the Electronic ignition plate and reinstalled the original points, set them to exactly 17 degrees. Reset the timing again.
Finally I am able to get this engine to idle smooth at about 600 rpms or enough to allow me to easily shift. The interrupter switch works as intended. I understand idle has to be under 700 (actually 600) for this OMC shift switch to allow the dog clutches to reengage. Starts well now. It is shifting without stalling now. Next step is to get her in open waters and see if it will hit 4200 RPMs. Too windy today will try this week. Thoughts???
Between last season and this season I had the quadrajet rebuilt, bought a new 1/4" carb gasket. Installed new risers, had the intake boiled out, had the heads rebuilt, new exhaust manifolds, installed a new Carter fuel pump, changed the one way hose valve for the gas tank, removed the gas tank pickup to make sure it was clean, changed the gas tank hoses and vent, changed, New spark plugs, wires were changed last year, cap and rotor were clean. I installed a brand new electronic shift interrupter switch. I also installed a new electronic ignition which was specifically made for electronic and or old fashioned points ignitions. All of last year it would stall at 2500 rpms and above. This year I pulled the distributor. Was told by a mechanic no wobble looked ok. Reset timing to 3degrees. Now I can get to 3200 - it wont stall however it will not get up to 4200 where it should be WOT. After all of this it still stalls when I lower the idle enough to try to shift and the idle is lumpy. Therefore I decided enough and removed the Electronic ignition plate and reinstalled the original points, set them to exactly 17 degrees. Reset the timing again.
Finally I am able to get this engine to idle smooth at about 600 rpms or enough to allow me to easily shift. The interrupter switch works as intended. I understand idle has to be under 700 (actually 600) for this OMC shift switch to allow the dog clutches to reengage. Starts well now. It is shifting without stalling now. Next step is to get her in open waters and see if it will hit 4200 RPMs. Too windy today will try this week. Thoughts???
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