Stange Problem - Need Help- OMC Dies

[asbennett]

Hi - You guys have been a great help in getting my boat back on the water this year - However, one last problem has me stumped. I have a 1982 OMC 2.5L I/O with a Stringer outdrive. 2 barrel Rochester carb, open freeshwater cooling, and fixed trim. Symptoms: After running open throtle for about 30 minutes the engine starts to cut out(miss) then die. I can throtle back to idle and the engine will run fine. Go back to full speed and it dies again in about 5 minutes. Sounded liek a fuel problem. I replaced the fuel pump (mechanical), checked the fuel lines, rebuilt the carb and added a new float. I still have the problem! It only does this after running for a while so it might be heat related. Oil level and pressure is fine, Cooling temp is normal, unit is charging, no smoke, noises, or sounds... just dies. Strange thing is it runs great for the first 30-45 minutes. Help!

 

[Boatin Bob]

Re: Stange Problem - Need Help- OMC Dies

Maybe check your fuel tank vent, if it's partially plugged you could be building up a vacumm in the tank, easy way to check is the next time you have the problem try loosening off the gas cap, this will release the vacumm if there is any.

 

[DJ]

Re: Stange Problem - Need Help- OMC Dies

OMC Stringer,<br /><br />Check the voltage going to you ignition coil. If it's more than 10 volts, you need a resistor in the line to drop it to about 9.5.

 

[asbennett]

Re: Stange Problem - Need Help- OMC Dies

I will check the voltage - one thought - Could this be related to the Lower Unit in any way? I drained the gear lube and noticed it was milky - I assumed it was just bad seals. Could this cause the engine to "bog" down as the lower unit heats up. Although it doesn't act like the engine is "straining". It just cuts out once or twice then dies unless I throtle back.

 

[DJ]

Re: Stange Problem - Need Help- OMC Dies

OMC,<br /><br />I doubt it. But, you had beter reseal that L/U or you're looking at big $$$ down the road.

 

[SeaNile]

Re: Stange Problem - Need Help- OMC Dies

You either have a cloged fuel line, filters, or bad fuel pump. Check the vaccume in the fuel tank to see if proper air is getting in. You may also want to check your distributer advance, points, timing, and the coil to see if they are up to the specs. Does your drive whine while in gear? If so then you have to reseal that thing.

 

[asbennett]

Re: Stange Problem - Need Help- OMC Dies

The strange thing is it runs WOT for the first 30 minutes. Then sputters and starts to die. I throtle down and run 5-10 MPH just fine. Speed up to WOT again and in 3-5 minutes it dies again unless I throtle down each time. Strange - I know.

 

[BigBabyLou]

Re: Stange Problem - Need Help- OMC Dies

As bob mentioned before:<br />

Maybe check your fuel tank vent, if it's partially plugged you could be building up a vacumm in the tank, easy way to check is the next time you have the problem try loosening off the gas cap, this will release the vacumm if there is any.

Your problem really looks like vacuum buildup in the tank.<br />Check it and if that's not the problem, I would look into fuel filter and pump.<br /><br />Keep us posted.<br />Lou

 

[William B Arthur]

Re: Stange Problem - Need Help- OMC Dies

So, what did it end up being? This was the exact problem I am having with mine. I better check the tank out!

 

[DJP]

Re: Stange Problem - Need Help- OMC Dies

I like the vapor lock idea best, good call Boatin Bob from Toronto.

 

[medic]

Re: Stange Problem - Need Help- OMC Dies

Same problem here. What was the remedy?

 

[asbennett]

Re: Stange Problem - Need Help- OMC Dies

OK - the final results are in on this problem... The culprit was the ignition coil. Once it was hot it would die unless I was at idle. This has fixed the problem. While I was at it, I also replaced the points and condensor. Good Luck to those still searching.

 

[medic]

Re: Stange Problem - Need Help- OMC Dies

Thank you.