Lightwin 3 HP gets hot

[wick83]

So the other day I acquired this 52 or 53 Evinrude 3 horse before I even attempted to start it I replace the impeller and did a carb kit and clean the place up and reset them. I have it to where it will run fine, except after running for a few minutes the power head gets extremely warm and I shut it down. Now I’ve taken the motor flush plug out while running to make sure it’s getting water to that point and it is getting a good amount coming from the hole. I have water coming out of the exhaust Outlet down below that never really seems to get too warm I’ve tried to blow air and flush out the Porsche behind the cylinder head and the one in the exhaust cover but still keeps getting way too hot any ideas?

[lindy46]

Those little motors run pretty hot. If you’ve replaced the impeller and have a good spray of water coming out, it’s most likely ok.

[wick83]

but it got so hot that it burnt the paint off the head, that was the first time I realized it was getting hot. I head left the motor running in my tank and walked away for about 3-4 minutes and came back to it not running and smoke coming off of the cyl head. At this point I left it alone to cool before looking into the problem. And this is when I tried to flush the powerhead out the best i could. But the same thing keeps happening except I’m not walking away whilr it running now.

[beerman57]

That was hot, feel like pulling the cyl. head off? I think I would.

[fleetwin]

You mention replacing the impeller, was it broken apart? If so, little pieces of impeller debris love to jam up cooling passages. You are sure the water pump impeller housing is OK, and the water tube grommet is not pinched, how about the sealing surface between the SS impeller plate and gearcase? I know you mentioned that there seems to be a decent spray mist coming from the exhaust reliefs, but that doesn’t mean the cooling system is AOK.
Did the engine appear to have overheated before you worked on it? If not, I would suspect something is not quite right with the water pump, perhaps the water tube is bent and rubbing the driveshaft also. Otherwise, it is time to pull the head and exhaust cover to clean out the tiny water passages. There is an elbow on the stbd side of the powerhead that loves to get plugged up as well. Sometimes, just running these little engines in our dirty test tanks (pine needles?) will introduce enough debris to plug things up as well.

[seakaye12]

I believe you are correct in your feeling that there IS a problem. Those engines have pretty small water passages that can (and do) get clogged with sediment etc.

I would pull the powerhead and check the grommet where the copper tube connects at the top…..and then pull the covers and look at the passages. Plan to spend some time figuring out exactly where the water flows. Some of the passages are hard to see.

If the motor was run in salt-water (as most of mine have) ….then there is even more reason to check these areas out.

Photo courtesy of Paul Moir

See the bend in the water tube? And see the Grommet (#12)

[wick83]

I have had the head off and cleaned the coolant ports the best I could but I think Ill have another look. This inst the first I’v worked on as a matter of fact its probably getting close to the 200th. I also pulled the exhaust plate and cleaned the small port in there. I’m pretty certain that its getting plenty of water up the tube as when i pulled the flush plug on the lower side of the powerhead it would shoot water about 4 feet out the plug hole. the old impeller was whole and no veins were missing or broken, it was just getting hard and wanted to make sure that it wouldn’t be the cause of a problem. I like the idea of pulling the powerhead and inspecting te lower ports I’ll report back to let yall know what I find and maybe get some pics up. Thanks for the helpful replies.

[wick83]

Well I pulled the power head off and looked at the bottom side she is full of neglect. There did appear to be some debris plugging a few of the holes, blew it out with the air hose as best I could blew air again through the pickup tube that seemed to be very open and clear we’ll see what happens in about an hour when I get a chance to run it again

[Brent Bergen]

I own a several of the OMC threes, and they definitely run on the hot side. Before you left it to run unattended for a few minutes, were you running it at a high rate of speed? They heat up very quickly at high RPM, and may not be able to cool down in a barrel without shutting down for a while. That tank water temperature just keeps going up with run time which leads to a hotter motor, which leads to hotter tank water.

Larger motors just seem to cool better, but with the threes they can easily be overheated in the tank. The flush plug is showing good flow, but as you know, that is prior to the water entering the powerhead. With both the plug and the relief ports having good flow, it seems as though the impeller, water tube grommet, and water tube are functioning ok. Still, pulling the powerhead and cylinder head, and blowing out the cooling ports with compressed air is something that can only be a good thing.

Improvise-Adapt-Overcome

[wick83]

Well after cleaning the debris out underneath of the powerhead blowing air through seems to be pumping water find through the power head now and staying Within it’s heat range

[Author]

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