1991 4.3 OMC Cobra starting problem

[packinjack]

I have a 1991 4.3 OMC COBRA motor, when I am getting ready to go out I usually fire it up in the driveway, now I hook up the flusher and garden hose, and it starts right up no problem, shut it off and restarts right away. Now I tow it 15 min. down the road, put it in the water, turned it over and it won't start, I tried spraying a shot of ether in the carb with no luck. Pulled it out, came home and the next morning hook it up to the hose started again right away with no problem. Ran it for about 15 min. shut it off and restarted right away. Then let it sit for about a half hour and tried it again this time it would just crank but not start. Next morning hook it up to the hose started again right away with no problem. Thanks in advance for your thoughts!!

 

[a70eliminator]

Re: 1991 4.3 OMC Cobra starting problem

An engine will start easier on muffs with no exhaust backpressure to overcome as compared to a submerged exhaust. A basic tuneup will probably cure that. The engine will also idle a slight bit higher on land than in the water.

 

[Big_Eddy]

Re: 1991 4.3 OMC Cobra starting problem

When it doesn't start - what's the issue? Number 1 question - do you have spark? Could be as simple as a loose wire between the distrib and coil, and depending on temperature or road vibration it makes or loses contact.

If you do have spark - then timing and fuel are the next things to check. Timing is probably fine if it runs in the driveway, so check the choke linkages and choke plate. If it starts cold but not warm - it's often a choke issue. Look where the temperature sensor is attached to the linkages - is it sticking in the "cold" position?

If you don't have spark, then it's something to do with the plugs, the distrib, the coil or the points. All kinds of things it could be, but pretty simple to work backwards and troubleshoot.

 

[LowSpeedChase]

Re: 1991 4.3 OMC Cobra starting problem

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[cr2k]

Re: 1991 4.3 OMC Cobra starting problem

After you run it check you carb throat to see if it is flowing gas into the carb. Either bad float or plugged anti siphon holes in carb.

This would flood the engine between home and water, starting fluid would make flooding worse. When this happens try starting at WOT (ready to back it off) and see if it fires after a while. (flooding)