Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

[Henkies]

Hi,

I bought a 3hp evinrude and new coils, points, capcitors. It runs now, but not smooth. Sometimes for 5 minutes, sometimes for 2. And the first time for almost 10 minutes or so. It turns very hot, and I'm affraid that's why it turns of. When I splash water against the cylinder head it instantly boils. The last time I started it, the revs are going up and down, up and down, etc, till the engine stops. I've opened the exhaust cover and it looked fine there, everything clean. The carb is clean as well. So now I have the following questions:

- To save time and money, where should I start checking the motor? I'm not from the USA, spare parts are 3 times more expensive here.
- How can I determine if the impeller is fine? I don't know if it is ever replaced, since I just purchased the motor.

Many thanks in advance!

 

[Daviet]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

Start by dropping the lower unit and checking the water pump condition, if any doubt replace the impeller.
Once you get the cooling system operating properly, double check the point setting, should be .020, make sure the spark will jump a 3/8" air gap and is bright blue.
The surging could be a dirty carb, pull it off and give it a good cleaning.

 

[Henkies]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

OK, thanks so far. I was trying to drop the lower unit, but couldn't.
What size are the bolts of this lower unit/gearing case? I'm in Europe and my Evinrude is made there, but these bolts aren't metric, since my M11 wrench is too small and the M12 too large.

The exhaust gas contains water by the way, so it circulates at least a bit...

 

[Daviet]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

If I remember correctly, they should be 7/16".
You might be able to use a M12 6 point socket if you have one, will be a little loose, but might work.

 

[Henkies]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

I've opened the lower unit. Looks like something was wrong with the rubber grommet in which the water tube (upper end) slides. It was almost closed. But it is probably worn anyways, and the grommet in the pump housing as well. They don't fit very tight around the copper water tube. The tube slides quite easy in and out. Should I seal it or can I make new grommets from some rubber tube?

 

[Daviet]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

There needs to be a tight seal there, if you can make them, go ahead and do it. Is there anyplace you can get them locally? They are made with a couple of little studs on each side to locate them in the housing, the studs also hold them in place.

 

[nwcove]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

that part would be extremely hard to duplicate. im in canada and most parts here are almost double the cost than in the usa, thats just the way it is. you should check the compression ( bad head gasket can cause an overheat). then source the parts in the most economical way. its still alot cheaper to fix that little bullet proof motor than to buy a modern "disposable" 3hp. jmo

 

[topekabill]

Re: Overheating Evinrude 3hp ligh/yachtwin (3632E 1966)

I have a 3 hp Johnson 1965, very similar motor. Had the same problem overheating as you do. After all the normal stuff changing the impeller (rotor) the old one looked new but changed it anyway. Same problem. The solution to my problem was to remove the exhaust cover, remove the the head, removed the center leg (transom mount). This gave me access to the water passages. the hole from the tube to the side passage was almost clogged with calcium. The hole from the side passage to the head was totally blocked (calcium) and did not give any idea a hole was there. Once I cleaned the passages and put it back together the thing ran like it was supposed to. This seems to be a complaint about this engine that it runs hot.

The water runs from the pump, up the tube, into a passage covered by the exhaust plate, through the passage into the water jacket around the cylinders, and out the exhaust.