Ignition timing on 93 4.3 omc cobra?

[Fourwinnsman]

I cannot find out how to check/set the timing on this motor. I have searched and searched. I do have a timing light but it is just an old regular flashing one. Do I need an advance one? I have read something about setting the distributor in base mode but cannot seem to find out how to do that. Boat seems to run strong when given throttle. But the idle is not steady and smooth it sounds lopey as if it has been cammed. (It hasn't).

 

[Fourwinnsman]

I have checked the timing with my light. It is at 12 degrees btdc. Idling around 800rpms on muffs in my driveway I know it is supposed be 600 but it really does not like low rpms it gets more stumble. Besides the higher idle, is this the correct timing? I am running 87 octane pump gas.

 

[Lou C]

I don't have specs on the later model OMC 4.3s but I can tell you the older ones like mine were set to 6*BTDC. So that sounds too advanced. Yours has electronic ignition, correct?
Someone needs to look this up in a '93 OMC shop manual, I only have one for my '88 which is an ancient points distributor set up the old way.

 

[Fourwinnsman]

I don't have specs on the later model OMC 4.3s but I can tell you the older ones like mine were set to 6*BTDC. So that sounds too advanced. Yours has electronic ignition, correct?
Someone needs to look this up in a '93 OMC shop manual, I only have one for my '88 which is an ancient points distributor set up the old way.

Yes electronic distributor. On a good note I just rebuilt the carb and now it is idling very smooth. I will try setting it to 6 degrees btdc and see how it likes it. I thought 12 btdc was too advanced as well. If anyone knows the exact numbers that would be great. Thanks!