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91 johnson overheat no water to right side

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Frustrated Steve

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"I have a 91 Johnson 60 degree

"I have a 91 Johnson 60 degree and the water discharge is strong, and the left side is very cool. The problem is the right side gets hot as hell, so I pulled the thermostat & just had steam coming out. I started the thing with the thermostat out & cover off. There is a strong stream of water coming out of the discharge hole, but still just steam coming out of where the thermostat goes, no water is visible in the head at all. Any ideas what is clogged??? The engine ran fine when it was last run, but that was 5 or 6 years ago."
 
"Don't know what I was thi

"Don't know what I was thinking. it is an Evinrude V6 E150EXEIS, not a Johnson. Sorry about that."
 
"Correct me if I am wrong, but

"Correct me if I am wrong, but even if the impeller was weak I am now running it im my yard hooked to a hose with a good bit of pressure. I wouldn't think so, but could it still be blamed on the impeller being bad?"
 
"Check the thermostat on stb s

"Check the thermostat on stb side, if that is stuck open and te waterpressure for some reason is a bit low, impeller, this may happen. Do not run without thermostat on any side."
 
"Thanks for the info. I'll

"Thanks for the info. I'll check that tomorrow. I should know better than to run it without the thermostat, but being curious, I had run it for around 30 sec to see if any water pumped out of the thermostat housing, but nothing but the steam. I also should have said that the Port side is the side overheating, but I'm too used to using car terms."
 
"I know that it is a common be

"I know that it is a common belief that an outboard should not be run without the thermostat, but there are only two things to consider. One is water temp. If you live in a cold water area it is needed. If you live in a warm climate it is not. The other issue is back pressure which regulates flow. I cut out the center of my thermostats years ago and have never had a cooling \flow problem. If you completely remove the themostat you can get poor water contact in the cooling area."
 
"Steve: Just check that both a

"Steve: Just check that both are closing properly (when cold).
James: If You knew a litle more about two stroke combustion engine and outboards and how they are designd you might reconsidder. Getting an engine to run cold is normally not a problem, but the idea is to make it run at a temperature where you get optimum combustion and minimum of carbon build up. That is a fine balance of temp/oxygen/ carbon (fuel). Change one and You will have to change another to get balance. Why do a cold engine normally need choke?"
 
"Morten, Thank you for your in

"Morten, Thank you for your input but being that I live on the Gulf Coast and operate exclusively in warm months in salt water, the option I have chosen is preferred and most common on the Gulf Coast where the water temp remains warm.... I have seen several engines ruined by corroded thermostats. I have never seen one ruined with the method of altering the thermostat in the way I listed. When you are 20 miles in the gulf it is much more important to have a running engine, than a perfect, optimum combustion profile. I can point to several instances of thermostats shutting engines down in perilous situations in the Gulf. The salt forms a corrosive sediment that will over time shut down the thermostat. The question is not if, but when. It is safer to eliminate this possibility."
 
"I am in Ohio & this engin

"I am in Ohio & this engine has never been run in salt. I might clarify that when I said that the 1 side gets hot as hell I meant that it heats up so much that the buzzer goes off. Morton did bring up a good point that leads me to believe the other thermostat is staying open. That is that I can't believe how cool the starboard side was, It wasn't cool to the touch, but it was just a little above warm. I wish I had a real temp guage to use, but I'll check the other thermostat tonight. Thanks guys for the input so far. Boards like this are great!"
 
"Test by swapping the thermost

"Test by swapping the thermostats. If that doesn't work then you have scale buildup in the passages on the hot side (and yes, scale can come from running in fresh water)."
 
"Steve,

The thread is kind

"Steve,

The thread is kind of difficult to follow at this point, but I would say that if you removed the stat, and ran the engine, and did not find any water coming out the stat hole, there is definitely a blockage somewhere. I have done this many times, and can tell you that you should see quite a bit of water coming out. If the other bank is running cool, the water pump must be working.

As for the discussion about the necessity of thermostats (I should know better than to get involved), but I think that drilling a tiny hole in the top of the stat is a good idea. I have done this many times without a problem. It does not have much impact on operating temperature, but it allows a little flow at all times. It is especially good if running in saltwater. Salt build up frequently freezes relief valves, stats and other things. If you are going to use stats, you should remove them for inspection frequently.

Tony"
 
"Gday Steve
A 5 or 6 year old

"Gday Steve
A 5 or 6 year old impeller has a high probability of failure, (even if it is not the cause you dont want to fix the problem and then have your 5 year old pump cook your engine) you would be chasing your tail if your pump was bad, at least with a new pump you know you have to look elsewhere, 2 new thermos sounds like a good idea. While you have the box off put your hose on the water tube and see what flows out the thermo hsgs (covers removed, engine not running) remember the lower bank is going to fill first so once flowing out just cover it with your hand and see what comes out the other side, no flow on one side would indicate a blockage and maybe time to remove the cylinder heads.

Cheers Spanaman"
 
"I REALLY apreciate the input.

"I REALLY apreciate the input. Ok, I need to learn a whole lot more about the water path to figure this one out myself. In a long nutshell, and I'm doing things I shouldn't. - I tried swapping thermostats with no change, so I removed the thermostats & cover plugs then start the engine & immediately have lots of water out the discharge hole. About 20-30 seconds later water appears at where the thermostats should be & just pulses out on each side, but without much pressure, but it is a bigger hole. By this time the one head is still cool, but the other is getting sort of hot. I let it run like that for no more than another 10 sec till I shut it off & let it cool all the way down. I can't understand how the water is getting to the discharge with force, but not to the heads unless the head gasket is blown on the hot side. Does this make sense? I can rebuild car engines, so I know the components, but 2 stroke coolant path isn't my strong suit. I may have to take it in instad of bugging you."
 
"Do any of you know a good boo

"Do any of you know a good book, other the clymer or diagrams on Evinrude's site that explain how 2-stroke outboards work? After looking at my last email, I didn't mean to say that you needed to teach me this."
 
"This engine doesnot have norm

"This engine doesnot have normal head gaskets, but o-rings. What is essential is that one has to be careful when applying sealing around the coling passages not to block the passages and to keep as much metal to metal contact as possible between the head and block. I suggest You take down BOTH heads and change the o-rings and clean the water passage holes."
 
"Sounds like a plan. I'll

"Sounds like a plan. I'll go to Paul's Marine tomorrow to get or order the O rings. Thanks for the info. Doing both heads makes perfect sense to me, why do just one, but there are those that would, so thanks for making sure I knew about that."
 
Do not forget a tube of GM sil

Do not forget a tube of GM silicone which is needed for sealing around the water passages.
 
"I would have forgotten that u

"I would have forgotten that until I went to put it back together. Thanks! Saved me a trip, and time. I also found that O rings are less expensive than I thought, but that's online."
 
"Changed the O-rings on both h

"Changed the O-rings on both heads and have it back together. I got lucky the marina had a special order of the o-rings, so they had them. Back together, seems to run fine. Taking to the lake in a few minutes."
 
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