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1975 Evinrude 15hp water on both spark plugs

J

jasondr27

New member
Would anyone know why my engine would start and run good even at full throttle and after a few minutes at medium to full throttle range the starts to "bog" out and loose powwer? It dont stall or quit running right away when I roll the throttle back to idle, but will after around 20 to 30 seconds later. So I took the engine back home and checked the spark plugs and they both had water on them along with fuel. The plugs did not look all to bad but I just don't know where the water is coming from. Any help or suggestions on this would be greatly welcomed. Thanks!
 
Thanks for the reply! I checked the fuel in the tank and I am good there with no water. Tomorrow I will get a compression tester and give that a try. What is the ideal compression that I am looking for?
 
Ok, got the compression tester and with both plugs out I put it in the top cylinder got 110 psi and on the bottom I got 115 psi. Not sure if I am doing it right but once I screwed in the compression tester I pulled the recoil string about 4 to 5 times quite hard. Maybe I'm doing it wrong but never really used one before on an outboard. So is this right or am I doing it wrong?
 
I did check the fuel tank and I did not get any water out but I will try a different tank with fresh fuel in it tommorow, thanks so far!
 
This may be a dumb idea but could he put some de-icing gas additive into the new gas he mixes up. I believe the stuff is supposed to absorb any water and allow him to burn it away. I am thinking about any water that might be in his carb bowl, as we speak. I have never tried it on a two stroke outboard but it did fix a frozen fuel line for me on a carbureted car back in 1982.

Boy that was cold day and you know it always gets a lot colder when the motor stops.
 
As joe suggested in post #3, pull the head and inspect the head gasket. It is possiable for a head gasket to leak water into the cylinders and still have good compression.
 
I am going to be trying it out in the morning with new fuel but just in case it still gets water in it I have ordered a new head gasket that will be here in the morning just in case. So we will see come tomorrow what will happen. Thanks for all the info and I will keep you posted.
 
Please report back if you pull the head. I have a 9.9 75' that I may pull the head on as well.
Let me know how hard it is to get those lower bolts out. Replace the thermostat while you are in there.
 
Well I have tried the engine with a fresh rebuild on the carb and a new water pump, since I was already working the engine. Put it in the water today for about an hour and went thru a about 1 1/2 gallons of fresh gas and oil mixed 50:1 with some Sea Foam in it and it worked good. As much as I would hate to say it, I think I had water in my fuel tank. Even though I though I had checked it, the new tank with new fuel proved it. Thanks for everyones help! As simple as it seam, I never thought about looking at the fuel since it was only a week old. Thanks again!!!!!
 
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