overheating dumb mistake

[Towman066]

I have a 1975 Trojan 25ft boat with 318 chrysler fresh water cooled when I ran engine I forgot to open up sea cock and ran engine for about 5 minutes before I saw steam coming from exhaust and no water, could someone tell what to check and what damage I caused. Thanks for and information on this dumb problem.

[mikeandanne]

Probably ok except you will have destroyed the raw water pump impeller that feeds your heat exchanger to cool the antifreeze......change out the impeller and give it a shot to see what happens but if you did not run it under load for that length time ( 5 Min) my guess is you will be ok,( heres hoping)

Now if you mean your engine has no heat exchanger and is cooled by lake water etc the same thing would apply in my opinion, nothing to lose except the cost of a new impeller....

[Big D]

See if your exhaust hoses still feel solid too. Best to remove at the elbow and check the inner wall. That's a lot of heat for 5 minutes. If there's any doubt about their condition, replace them. Not sure if your exhaust manifolds are closed cooled or not but check any hoses, wires, cables, plug wires etc., that are in contact with the exhaust manifolds. You're looking for anything that might be melted.

[WayWeGo]

If you destroyed your impeller, you should look downstream from the raw water pump and make sure none of the impeller pieces have traveled there and clogged up the system. If you can piece together all the impeller pieces, you should be OK. If not, I put a sock or stocking on the hose that I remove from the raw water pump and backflush each segment until I have all the pieces.

Don't feel too bad, it can happen to anyone. Last fall, we had friends aboard and I did the same thing. Got distracted and forgot to open one of the seacocks:

[prowlersfish]

All the above

[BobCT]

Definitely recommend a raw water temp alarm for exactly this reason. They're not expensive and an easy install. Mine went off last year and my initial reaction was "great, a false alarm I need to troubleshoot". Sure enough, my impellor vanes were broken. The alarm went off before my temp gauge even moved.

Bob