83 Johnson 90 hp

Riverrat8428

Seaman Apprentice
Joined
Feb 4, 2008
Messages
37
I had to change out the mid section on my 90 Johnson this winter. I am trying to run the engine now with a flush attachment and I feel something is not right, I have water coming out of the **** hole seems cold and water out the propeller seems warm. However there is water coming out beneth the power head somewhere and a large slot in the front of the mid section right above the cavitation plate. The cylinder heads feel hot. I disconnected the large hoses fron the Cyl head to the thermosstate housing and ran the engine but no water came out.. I replaced the thermostates while doing my winter job as well as new springs and bypass valves, the water pump I didn't change as I changed the pump last year. What do you guys think? Any help guys will be appreciated.. Another question How do by pass valves work?Riverrat 8428
 

flabum

Chief Petty Officer
Joined
Feb 17, 2007
Messages
567
Re: 83 Johnson 90 hp

What year was the midsection from?

Are you sure the powerhead gasket didn't slip out of place when you put the powerhead on?
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 83 Johnson 90 hp

Take a look at the attached diagram. It shows where the problem often is after the powerhead is replaced.
 

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Riverrat8428

Seaman Apprentice
Joined
Feb 4, 2008
Messages
37
Re: 83 Johnson 90 hp

What year was the midsection from?

Are you sure the powerhead gasket didn't slip out of place when you put the powerhead on?

I was careful and used a gasket sealer to keep the gasket in place, the mid section was from an 87 evinrude... I have removed the gear housing and put a garden hose diecectly o the water tube, with a light I can see some water coming out of the area where the tube enters the adapter.. should water be coming out of that are. If not what is involved in changing the grommet near the adapter plate?
 
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ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 83 Johnson 90 hp

With the garden hose connected to the water tube, open the two hoses leading from the cylinder heads to the thermostat housing.

With the hoses open and no thermostats to block the flow, the water should flow smoothly through the engine cooling circuit and out the two fittings as in normal open operation.
 

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Riverrat8428

Seaman Apprentice
Joined
Feb 4, 2008
Messages
37
Re: 83 Johnson 90 hp

I will be reassembling tomarrow and I think I may have placed the power head gasket on wrong a bad mistake in a hurry to leave for the Keys. Hope this is the answer. So far new pump and upper grommet and exhust tube gasket and new power head gasket tomarrow and than well try to run the engine. I'll let you know.... Thanks
 

Riverrat8428

Seaman Apprentice
Joined
Feb 4, 2008
Messages
37
Re: 83 Johnson 90 hp

We'll I took a five mile trip and things appear to be normal... I feel the base gasket mistake made in hast between going in for thanksgiving dinner and other pressure was the problem,, In the mean time I learned how to dissassemble the adapter plate change the upper grommet etc.. So now well start fishing in the Keys and see how she runs... Thanks you guys for your help......
 
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