1980 evinrude 9.9 cooling question

Kpenrod

Recruit
Joined
Aug 13, 2013
Messages
1
I have a 1980 evinrude 9.9 which had been sitting for 20+ years but was ran periodically and stored indoors. Before taking it out I did a complete water pump change and tested it several times with muffs. Water would come out tell tale but not a very strong stream but motor was cool. After around 20 minutes of running tell tale slows to a slow drip and water is pouring out of the two exhaust relief ports and the motor seems to be a little hot. There is also water coming out around the shifting rod hole in the lower unit. What could the problem be? Thanks so much for any feedback
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1980 evinrude 9.9 cooling question

Did you check to see if the water telltale outlet fittings or hose was clogged?

Info on the exhaust relief holes follows:

(Exhaust Relief Ports - Exhaust Housing (Inner/Outer)
(J Reeves)

The long housing between the powerhead and the lower unit is called the exhaust housing. There is a inner housing within it that has a heavy duty seal around the bottom of it, or heavy duty seals around a inner extension between the housing and the lower unit.

The red hot exhaust travels down thru that inner tube and out the propeller with a somewhat supply of water to cool the propeller hub. A good amount of water surrounds and fills the space between the outer and inner tube, otherwise the outer housing would get so hot that the paint would burn off.

Some water pumps, for some reason (differing even when new) exert a great amount of water pressure, and if the exhaust housing seals are in perfect condition, the water fills the tube to a point of overflowing.

This brings into play those two holes or slots, whichever the engine might have, at the top rear portion of the exhaust housing just below the powerhead.

Now, if those two holes/slots weren't there, water would continue to flow up into the cylinders. Water not flowing out of those holes is no concern for alarm UNLESS that outer housing suddenly becomes extremely hot..... the warning horn should sound long before that happens.

The main reason for those holes being there (exhaust relief holes) is that when at an idle, there is an extreme amount of resistance encountered by the exhaust trying to escape due the fact that the outlet via the propeller is now blocked by a wall of water. The escape route in this case is for the exhaust to escape out those two holes, otherwise the engine would slow down quite quickly and die. If exhaust cannot escape, air/fuel cannot gain entrance to the engine.
 

gozierdt

Petty Officer 1st Class
Joined
Jun 13, 2010
Messages
364
Re: 1980 evinrude 9.9 cooling question

When you ran the engine for 20 minutes and it felt a bit hot, was that all on muffs, or on a boat in the water? Since you describe several lower escape areas, I'm assuming you are on the muffs for all of this. And when you say the motor was "hot", do you mean "can hardly touch it" hot, or "I don't like touching it for more than 10 sec [15 sec, 20 sec?]). Also, if you restart the motor from cold, do you again get a strong tell tale stream, or is it always weak now? It's not uncommon for debris in the cooling passages to break off and partially clog the tell-tale port. If it's always weak now, you can take the hose off the outer fitting, and run a wire up into the tube to try and break up and move any debris.
 
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