Overheated 6 hp question

[Starkonian]

I have a 1971 Johnson seahorse 6 hp. Started on 1 pull and ran perfectly except occasional konking with a soft primer bulb where if I quickly squeezed the bulb it would keep running. I think this is unrelated to my question but mentioned it just in case. Recently on a 90 degree day it was smoking a tad more than usual and the cowl was hot to the touch which I dismissed as being related to the hot sun, stupidly I now realize. I started and ran it for several 3 -5 minutes runs as I fished around my small lake. It started to have a slightly different sound to it. Finally it whined a little and came to a metalic sounding stop. It would'nt start but pulled over with the rope with a normal feel to it. No binding or odd sounds at all when I pulled the starter rope. I cruised home on the trolling motor. At the dock I pulled it over a few times and it started right up and idled nicely for a few minutes but conked out and I then had to pull multiple times to get it started again. Unfortunately this was the last night up at the cottage and I had zero time to look at further but I did seem to note there was no water coming out the top exhaust holes. There used to be a fine mist coming out there; I think the majority of the water coming out the engine comes out another port below the water line. It's a used engine I've owned for 5 years and have no idea if the water pump/impeller was ever changed so no doubt that has failed in my mind. My question regards an engine having a "soft seize" where it never permanently locks up other than an intial stop like what happened to mine. I'm wondering if it is toast or can these keep running after something like this. I've even read you can pour a couple table spoons of "Engine Restore" available from auto parts store directly into each cylinder that has good results if there was some minor piston cylinder scuffing/scratches. Sorry for this loooong post but wanted to relay the most/best info I have. Thanks for any assistance. Pete

 

[floatingwoody2006]

Re: Overheated 6 hp question

Well.. You can only hope for the best dude. If it was me i would first take a compression reading with both plugs out, and see how it looks. readings within 5-10% of eack other is a good thing. Higher the better of course. If that looks ok, replace that impeller with all associated parts, and see how she goes. Compression check is your first thing to do. If it's low, you may want to spend short money on a new head gasket to see if it helps. good luck.

 

[Mojo700]

Re: Overheated 6 hp question

You will probably see discoloring of the head (on an Evinrude it turns a golden color from the original blue/gray) if it has been really overheated. If this is the case, the head gasket will probably be loose, and the gasket will have to be replaced. Also check for water leaks (once you have new water pump) around the exhaust manifold. If you remove the exhaust manifold and head, you'll be able to see most of your cylinder walls, and the exhaust side of the pistons through the exhaust ports in the exhaust manifold (which is usually hottest), from there you'll be able to determine if it's worth repairing. If the piston or cylinder has "stripes" that you can see, but don't feel too deep, it'll probably be okay. If the piston or cylinder have "gouges" it probably needs a top end rebuild, and it's usually a better bet to buy another used motor. Good luck, Mojo