4 Hp Evinrude, TLC part 2

[bill fish]

Hi guys....<br /><br />Posted a couple days ago about my 4 Hp Evinrude, model # 4806E, 1978.<br /><br />Regapped the plugs to .03 from the old .05 and still plan to do a decarb this weekend.<br /><br />Put the engine in a large garbage can and ran it this evening...<br /><br />Changing the spark gap helped a lot and it seems to start more reliably under various conditions now....<br /><br />However, I got to wondering how well the water pump/cooling was going...<br /><br />With ALL the churning and foaming in the water....I could not tell at all where the cooling water comes out or even IF any was...<br /><br />Were is the cooling water exit on this little motor?<br /><br /><br />Then, I got to touching various parts of the engine with my finger.<br /><br />The "head" (the metal plate that the spark plugs screw in) was very hot to the touch, anything more than a momentary touch started a burn...<br /><br />On most places on the the "block" itself, I could keep a finger on for a few seconds, and some spots a lot more than that....<br /><br />Except for one place. Looking at the engine from the rear direction (so that you see the head and spark plugs), there is a roughly 3 inch by 5 inch thin flat metal plate bolted to the left side of the block....now that plate was hot as all get out as well....<br /><br />Does this sound normal/reasonable?<br /><br />Oh yeah, does this little motor even have a thermostat?<br /><br />take care<br /><br />Blll

 

[Xcusme]

Re: 4 Hp Evinrude, TLC part 2

Bill, Your motor should have a horizontal row of small idle relief holes on the rear of the leg. These holes will 'spritz' a fine spray of water if the water pump is working. I pretty sure your motor does not have a thermostat. My '73 and '76 don't have them either.<br /><br />The metal post on the side of the powerhead that gets really hot is the exhaust cover port and it should be hot, that's normal.

 

[Paul Moir]

Re: 4 Hp Evinrude, TLC part 2

No, there's no thermostat.<br /><br />The head gets pretty darn hot on that engine. If you get signs of preignition on the spark plugs or they read 'too hot' then I suggest you pull the head and clean out the cooling passages. A new head gasket is something like $3 for that engine, but you may need to get a new powerhead base gasket as well if you have to remove the powerhead to access the head properly. Don't forget you'll have to torque it to spec to put it back on.

 

[Chinewalker]

Re: 4 Hp Evinrude, TLC part 2

The exhaust cover is not cooled on that motor, so it will be very hot to the touch. I've also found that the cylinder heads on those motors also run fairly hot, due in part to the water only circulating around the edges . The motors are simply too small to receive the "deluxe" cooling treatment that the big motors get with multiple passages, thermostats, telltale pissers, cooled exhaust covers, etc.<br /><br />As was mentioned, you should get a good mist of water out of the holes in the rear of the motor leg below the clamp bracket assembly. No mist, no cooling. If you're uncertain of the waterpump impeller's history - replace it. I can do one in about 15-minutes (assuming no broken bolts, etc.). New impellers un about $10-$15. Buy/borrow a manual for your motor before starting - well worth the investment.<br /><br />- Scott