5.5 Evinrude blowing a gasket

[DavidH]

Please! Help!

I have an older ('57) 5.5 Evinrude Fisherman that keeps blowing a head gasket all the time. It's (the gasket) been replaced 4 times in the past 4 weeks. What would be the cause of this? The head has been replaced once already.

It's getting a very tiresome to constantly replace the gasket on this motor.

Is there anything I can check to see why this is always happening?

Thanks

[Surface Tension]

Sounds like the head is warped. Bring it to an automotive machine shop and have it planed.

[DavidH]

Thanks for the reply.

The head has already relaced once before. I assumed that the new one wasnt warped. Is this a common occurance that these heads get warped?

Is there anything else that would be causing this?

[mnrstrider]

Maybe improper torque sequence or too little or too much torque in some or all spots. I'd still lean towards a warped head or engine block.

[Surface Tension]

I was thinking improper torque also. Other then that or warped head, overheating is another possibility. Have the head checked. Re-torque the head bolts after 100 hours of use.

[DavidH]

K...thanks for the advice.

I'll give that a try and see how she goes.

[Knotwood]

I wonder if you can do a compression test on it, where does it blow? The reason I'd ask is if there is some sort of hydraulic lock thing going on if it warms up and pulls water in from a jacket or crack, causing too much compression. Or a loss of coolant causing it to overheat and warp. Try a cold compression test first, then try it (maybe in a barrel) after it's been run for about five minutes, then after about ten, see if it changes dramatically.

[ccarlson]

DavidH,

I have the same motor. It was my grandfathers and I'm trying to keep it in working order for sentimental reasons. I tore it completely apart for new seals and rings.

I have a question for you though. I can't remember exactly how the air filter assembly in front of the carb came off. Does the foam piece go right next to the carb and then the metal screen next (in other words, sandwiching the foam)? That is what I assumed but it doesn't seem to be breathing correctly. Then I thought maybe the metal screen goes on and then the foam but that didn't seem to make sense. If you can tell me how yours is put together it would help greatly. If I have it correct, I'll just put a new piece of foam in that may breath better.

thanks,
ccarlson

[Knotwood]

Sandwich the foam, it keeps it from getting into the carburetor throat.