140hp Evenrude Blown Head Gasket

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

If you were sure that the mating surface on the block is in good shape I wouldn’t be concerned with the gasket for now, take the head off and bring the piston to the top of the stroke and check for a slight bit of motion between the cylinder and piston, which would mean to me that the rings are free to move. It’s not good if the rings are locked.

Did you notice a rust ring on the cylinder wall when you first got a look at it? Saltwater did enter the cylinder and if it had enough time would have caused the ring to rust and stick to the cylinder wall. It’s good that the piston still moves.

If there is movement, and the worm grooves are on the head only, then have the head machined (my guess is a fifty buck job). The gasket is probably done for as general use but should work to do a compression test. If the cylinder comes back to life I would pull the other head and have that machined and replace both gaskets.

There was no rust in the cylinders and they have never been frozen. I lubed everything up in there and stuck a dry clean rag in both and one over them before covering it for the few days before the head gasket arrived.

Very helpful Even/John mechanic at the local shop suggested before machining (he might even have a good used head laying around) that I do a decarb and get it warmed up and then re-torque. He said the compression is not terrible. If I can get another 5psi out of it I would be in range and I’ll let it go. He mentioned that the warming up of the gasket and re-torque might just do the trick if its a leak at the gasket. I’m going to try that tonight and see how it goes.

If not I’ll go with the machining or a used good head. I’ll do your ring check thing at that point as well.

Thanks for the help Ill report back once I have a solution or not.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Decarb and check compression again. Just my thoughts though.

This: 1/3 seafoam to gas for 10 minutes along with re-torque while warm (all the bolts took another 1/4-1/2 turn or so) fixed the compression completely - well its better than it has been since Iv owned it! The top and the bottom are now around 123 top and 125psi bottom. Ill recheck compression after my next Salmon slaughter, but it was running realy nice after the process.

I’m extremely happy right now Im sure you know what I mean - thanks for everyone’s help.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

So I replaced the port side gasket. It looked ok but glad I got it done. The motor is running way better then when I got it - more power and less vibration at idle.

The top port side compression is way higher then the others its 145psi. The others are low port 130, low sb 125, and upper sb 123. Is that bad? I though they were all supposd to be within 10%, but usualy its one low psi one not a high psi one.