evinrude 4hp

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gull1066

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Hi All,

I brought a 1985 4hp twin cylinder outboard, which is in great condition. It runs fine but seemed to pump no water.

After checking the impellor and the water system all seems to be ok apart from there seems to be no water jetting out to indicate water circulation.

When i removed the leg from the main engine I did see that the water passes through the head then comes back out and seems to just drop down into the leg and out the holes low down. seems a bit strange as you would have no visable way of knowing if water is circulating. I can see no other way the water will can come out.

Is that right? Any advise would be good.
 
Sounds like the same engine I used to have. If so, the cooling water exits through a seriesof about 6-8 holes on the leg just above the water. It comes out in such a way that you don't really see a jet but put your hand in front of it and it should be instantly wet with warm water.
 
Depends which model it is. The one in the link is the one which is a detuned 7hp I think.

I had the small 4hp twin which has a different water tube arrangement from the pump to the power head. On mine the gasket goo some one had blathered on the leg/powerhead joint had blocked the gallery.

blockedwaterpassage.jpg


In this shot you can just see the spray of mist coming from the eight holes in the leg about 6" above the water like neale says

testrun1.jpg


The holes

Evinrude4hptwin.jpg
 
Last edited:
gull1066 said:
Hi All,

I brought a 1985 4hp twin cylinder outboard, which is in great condition. It runs fine but seemed to pump no water.

After checking the impellor and the water system all seems to be ok apart from there seems to be no water jetting out to indicate water circulation.

When i removed the leg from the main engine I did see that the water passes through the head then comes back out and seems to just drop down into the leg and out the holes low down. seems a bit strange as you would have no visable way of knowing if water is circulating. I can see no other way the water will can come out.

Is that right? Any advise would be good.
Click to expand...

Yes that is right the 4 Hp models, unlike their larger brothers, do not have a telltale.

You should see some water droplets or a mist blown out of the back pressure relief ports on the leg if all is well.

Check that it is not overheating. You should be able to touch and maintain finger contact with the engine block briefly. (but not the head around the spark plugs or the exhaust manifold cover plate on the port side) If you cannot or a splash of water sizzles and boils it is overheating.

If you see steam coming from the exhaust relief port it is an indication that it is overheating.
 
Last edited:
neale said:
Sounds like the same engine I used to have. If so, the cooling water exits through a seriesof about 6-8 holes on the leg just above the water. It comes out in such a way that you don't really see a jet but put your hand in front of it and it should be instantly wet with warm water.
Click to expand...

+1

i have one very fine mist out of the 6/8 holes
 
I had an Evinrude 4 twin, can't say I have very happy memories, and have always wondered, 'why a twin at that size ?!'

Refitting the recoil spring at a bouncy berth in Weymouth will forever remain etched on my memory, I came out with a few naughty words and maybe invented a few new ones...

I think the most pertinent comment here is 'didn't have a telltale', ie one couldn't see a reassuring stream of cooling water from the engine.

However, I run my 5hp main engine & 2hp dinghy job ( both Mariner 2 strokes ) in fresh water tanks every chance I get - our club has a freshwater tank with an outboard pad to clamp onto at the top of the slipway, incorporated with the dinghy wash-down hoses, a great idea by somebody.

Despite a good run through on fresh water last autumn, when I tried them a week ago the 2hp gave no telltale outpouring; on taking the head & leg off it became apparent there was a salt build up blocking the waterway, despite a good 5 minutes run in oily fresh water...

So a long run and keeping an eye on telltale outlets, or in the absence of a telltale taking the thing slightly apart over the winter, seems prudent.
 
I have the Johnson version, which I think is the same engine with a different badge? In defence of it, having two cyclinders was a blessing to me. I used it for trolling (fishing) which involves crawling around on minimum revs for hours on end and inevitably results in oiled plugs. On the Johnson this was never a problem because I could just motor to the bank on one cylinder to clean the plugs. With a single that had to be done in the middle of a lake. Nowadays people use 4-strokes or electrics for that job.
As others have said, there is no tell tale jet, just some holes about halfway down the leg. If you put your hand near them you will get a light spray of steamy exhaust on your hand.
 
Seajet said:
Actually I was repairing the recoil set-up; managed it after a lot of sweat, cuts and swearing; it would have been easier to train a lion to do it ! :rolleyes:
Click to expand...
That's where is was when I got it (on the floor, bottom right). Yep, the previous owner thought the big screw was the cover screw.


uncoiledspring.jpg

That's where it should be

Evinruderecoilstart.jpg
 
neale said:
+1

Having said that I loved it. It was very very light and I found it ultra reliable too. In fact I wished I had kept it.
Click to expand...

I have still got it! It's in the shed. But I can't say it is very reliable, I have always had problems with blocked fuel jets. Then I had the bright idea of installing an in-line fuel filter between the fuel tap and the carburettor. This worked for half an hour and then the engine stopped. After much investigation, it turned out to be vapour lock in the fuel filter.

But it was our beginning in boating. We used to rent a dinghy and put the Johnson on it. But we soon realized we needed something more comfortable and reliable, so we bought our boat. Never regretted that so many thanks to the Johnson!
 
Sod me, thought I,d got one of the oldest outboards on the water,apart from Seagulls,Great little outboard,no real problems,impeller a bit awkward to change and fuel tank has to be kept clean or jet blocks up.Pretty thirsty but think it will last me out.Have a great Easter you guys and lets hope we get a good summer.
 
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