'83 Evinrude 115 V4 Overheating

Engine has been running great but today overheat alarm sounded. I had run at WOT for about 20 mins, 5000 RPM, with no discernable problems. Then ran for 5-8 mins jsut past idle to get back into harbor, then turned engine off at dock. When I fired back up 5 mins later the alarm sounded. Noticed water is coming out of pee-hole, good stream, but it is very hot. After a couple minutes in idle / just past idle while getting boat on trailer the alarm stopped, which I attribute to engine cooling off again. The water is chilly, 55 degrees. The impeller and housing is new, 6 hours on it.

Questions are;
-Should the overheat have happened at all or was I pushing it?
-Did I damage anything?
-Where are the thermostats located and how do I assess them?
-Back in the driveway, flushing with earmuffs, engine started up readily. Should I be seeing water exiting from the two outlet ports while just under muffs? Should I be seeing water exiting from the hub with the exhaust as well?

Thanks!

Re: '83 Evinrude 115 V4 Overheating

A strong telltale is a sign that the impeller is pumping water to the powerhead. When you are on plane, there are presssure relief valves in the thermostat housing which will open, flooding the powerhead with extra cooling water. These valves close when at dead idle, and that is where your overheat occurred. At dead idle, the water excapes from the block only through the two thermostats. If water cannot excape/exit from the powerhead, it will overheat-that's where the thermostat housing comes in. Likely one or both of the thermostats in that housing is bad-stuck closed. I'd take the housing apart and consider replacing both stats. Also, make sure the pinhole(s) in the valve body are open. If these pinholes plug up, as they tend to do, the powerhead will overheat. The thermostat housing is located at the rear of the engine between the two cylinder banks, at the top of the exhaust housing. (Look for the two hoses from each cylinder bank.) You will find this is an easy job if you have the factory manual to refer to.

Re: '83 Evinrude 115 V4 Overheating

I see the thermostat housing, looks tricky to get to the three bolts - I see some people have suggested putting a couple holes in the plastic casing just to turn the bolts.

Looks like a number of possible stats and kits available, do you know what temp. rating or a rebuild kit part #?

So when in idle, the cooling water goes thru thermostats only, but then where does it exit?

Thanks!

Re: '83 Evinrude 115 V4 Overheating

The thermostat housing access problems are generally only on the bubble back 140's and later 115's. Yours is not one of the problem ones. Your replacement stat will be around 143 degrees. I'd pull the housing apart first and see if anything else in there needs replacing, like the nylon pressure relief valves/gaskets or rubber parts-then buy all your parts at one time. The thermostat housing directs the used cooling water into the midsection.