Cobalt Boats Forum

Pull the distributor cap and clean the contacts & rotor. (It has a distributor and not coil-on-plug, right?)
Easy and cheap first steps...
Pull a few plugs to assess condition in addition to the above suggestions.
Ignition switch is possible but I don't go in this direction first since a warm start ...

ok. Thanks for that. I'll keep searching for a cause.

Put it on the water yesterday.
Ran it for a couple of hours at all sorts of speeds, long durations at 30mph. Several WOT runs, lots of idling, etc.

It stays cool throughout (under 175) during all of that ...until I come off plane and the engine returns to idle. At that point the temp rises to what ...

Shaft appears fine. The props came off and went back on with no binding if that is a reasonable way to assess a bent shaft.

Going to try the cylinder switch actuation soon. Thank you! Mine's doing the same thing, has been for years. I tap it and it responds but I'm starting to just ignore it.

Ever figure this out?

'99 Cobalt 253 7.4 Volvo DP. Open cooling, fresh water use only. 350hrs.

I hit a big log on the lake, bent up the props, got them fixed, reinstalled a few weeks later and went out.
Since then, when on plane at about 30mph, the gauge goes to 190 and will keep climbing until the throttle response is ...

bmac,
What did you come up with for a light?