cooling issue

I have a 78 140 that I know little about besides that it checked out with my mechanic and the carbs were just rebuilt back in August. I never ran it after the carbs were rebuilt and was fogging it for winter storage. Then the warning horn went off after less then 5 minutes of running. I noticed a good stream of water from the pee hole and nothing from the exhaust. The heads felt warm but not hot. This was with muffs and a garden hose. The water from the pee hole was warm but not hot also. Any ideas?

Re: cooling issue

You can have a good impeller in the lower unit, a strong stream out of the telltale and still overheat one/both heads. All the telltale says is that cooling water is getting to the powerhead. The telltale is plumbed close to the water entry point into the powerhead, so it may be relatively cool. It does not indicate that it is circulating through the powerhead, then being discharged into the adapter/exhaust. Basically, at idle the water must flow through the thermostat for each head (2 in the thermostat housing.) If one (or both) of them is stuck shut, that head (or both) will overheat and the hot horn will sound. May be time to pull the thermostat housing apart and install new stats. Also a good time to check out the two pressure relief valves. There is a bakelite valve body inside the thermostat housing. Make sure those two tiny holes in it are open. Good luck on this procedure-it will result in some skinned knuckles on that bubble back engine.