Engine shuts down after a little time on the water

[Roadguy330]

I have a 1990 Sunbird with a 5.0 OMC COBRA I/O. Starts great and runs great for a little bit on the lake (10-15 minutes) at wide open throttle. After a short period of time it shuts off as if you turned off the key. It will not restart. After being towed back to the dock (10-15min. or so) it restarts. It runs at 4200 rpms at 42 mph. While it is running it runs great without any miss or hesitation. Any help in this matter would be great. I have already lost a whole summer and had it in and out of the shop several times with alot of $$$ spent.

 

[64osby]

Sounds like a temp overheat shutoff of some kind.

 

[Scott Danforth]

My guess is the ignition module is starting to fail, or you have a loose connection somewhere. next time it fails, check for spark, and remove the spark arrestor and check for fuel when you give it throttle, you should see two streams of fuel being sprayed in the carb.

 

[Roadguy330]

Thank You guys, I'll look into this. The only problem is I can't duplicate it on a hose and the closest lake is 45 minutes away.

 

[64osby]

Drop it in your neighbors pool.

 

[appman@centurylink.net]

I have a 89 bayliner and tuned it up over the winter, mine did same thing all summer, ROTOR BUTTON , imagine that and I am old school never seen this

 

[Roadguy330]

Im not familiar with a Rotor Button.

 

[64osby]

Im not familiar with a Rotor Button.

Google it.

I would refer to it as the "rotor". Never have seen the "button" part.

 

[Roadguy330]

Appman, how did you determine it to be the Rotor?

 

[garbageguy]

I have a 1990 Sunbird with a 5.0 OMC COBRA I/O. I have already lost a whole summer and had it in and out of the shop several times with alot of $$$ spent.

What did the shop do? That might shed some light on the matter.

 

[jerryjerry05]

Different parts of the country and the parts names can change.
Roadguy is from the upper midwest (ohio) I'm from Michigan and we called it a rotor button????

Not sure they had a temp overheat shut down on that model.

Also not sure they had an ignition mod on that year.

They had points. What did the mechanics do???


It sounds like the coil's getting hot and breaking down??

What's the voltage into the coil?
I think it's supposed to be 9v.

Start it and let it warm up.
Then try touching the coil.
It should get hot but not so hot you can't keep your fingers on it.

 

[Roadguy330]

I ended up replacing the coil, rotor, points, condensor and distributor cap. I had it on the water for about an hr yesterday, it never shut off and ran pretty decent. It runs a little rough but I am going to replace the plugs and wires before next season and hopefully solve that issue. Thank You everyone for the input.

 

[bruceb58]

You set the points with a dwell meter and then check timing?