OMC Cobra 5.0 - Turns over but doesn't stay on

swanics

Cadet
Joined
Jun 25, 2012
Messages
10
I have a 1992 Reinell with an OMC Cobra 5.0L. Getting it ready for the season and it and turns over and will stay on if I have the ignition switch in the start position. I can rev it up while holding the key in the start position but as soon as I let go of the key it'll die. I tried replacing the ignition switch and that didn't help.

After trying to find loose wires I finally decided to try starting from battery #2, which is about 5 years newer than #1. It started up and I was able to let go of the key but then it soon died and started having the same problem. So I added some gas and tried again and I still get the same problem. I haven't been able to keep it on without holding it in the start position since. It seems like a loose wire but any insight would be helpful.

Thanks
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
You shouldn't have points in a 1992 but if you did, you could get power to the coil in start but not during run. Just for fun, measure the voltage at the coil in the run position. Engine doesn't have to be running. If you don't get voltage there, check your man overboard switch.
 

swanics

Cadet
Joined
Jun 25, 2012
Messages
10
Good call, I'm heading out of town but will give it a shot when I get back and provide an update. Thanks
 

swanics

Cadet
Joined
Jun 25, 2012
Messages
10
Coil checks out okay, I get power in the run position and I checked the ohms and they are at specs in both primary resistance and secondary resistance.

I tried testing the resistor wire which the boat has instead of a ballast resistor and I think it might be working. My multimeter slowly climbs up to 2-4 ohms and the slowly drops down below 2ohms and then back up. I don't know if it's a crappy multimeter, the fact that I didnt disconnect the wire from the alternator and coil, or the resistor wire is bad. I understand it's suppose to read at 2ohms from reading this:

http://forums.iboats.com/forum/engi...ves/279780-1988-omc-ballist-resistor-location

I'm going to disconnect the resistor wire and see if I can get a better reading. Please let me know if you have other ideas. Someone told me another way to try it out is to Hotwire the thing using the wires coming off the carb?
 

swanics

Cadet
Joined
Jun 25, 2012
Messages
10
After lots of work poking and prodding the thing with my multimeter I'm starting to think the gas is just bad or the fact that I didn't fog it this year are to blame. I switched to battery 2 again and was able to get it to run for a little while. After letting it run and revving it up for a few minutes it started working more consistently. I'll let it sit for a day or two then see if it will continue to start and run.
 
Top