piston ring replacement

[kybodyman]

I have a 1979 55hp evinrude that I suspect has a broken ring on the top cylinder. Is it possible to replace ring set with motor mounted to transom. Original shop manual on the way, just wanting a heads up as to what I am getting myself into.

 

[bonz_d]

Re: piston ring replacement

Nope! Crankcase needs to be split in order to remove piston.

 

[HybridMX6]

Re: piston ring replacement

Not true. The motor can stay on the boat, but you will have to pull the powerhead off the motor. Then you need to fully disassemble it to split the crankcase.

 

[bonz_d]

Re: piston ring replacement

Sorry but the way I interpreted the question was could it be done with the powerhead still in place on the boat.

 

[kybodyman]

Re: piston ring replacement

Thanks, not what i was wanting to hear but that's ok. You were correct about me hoping to do this operation with power head still attached. Any good prep work I can be doing while awaiting arrival of service manual? Also any kind of ball-park $$ amount I can expect to spend on parts and machine work for this job?

 

[bonz_d]

Re: piston ring replacement

Can go to shopevinrude.com and get all the part numbers you'll need along with getting an idea of how it's all put together. Like gaskets, seals, rings. Maybe even pistons if the cylinders are scored or way out of round.

Then while you have it apart you can get a good look at all other systems parts for wear or that could use replacement.

Machine work will largely be dependant on what ever you local shops will charge. May want to start calling around to get a ballpark on the machine work.

 

[kybodyman]

Re: piston ring replacement

with little or no compression on that cylinder, how will i test for blown head gasket as opposed to a broken ring?

 

[HybridMX6]

Re: piston ring replacement

The amount of money is going to depend on how much needs to be replaced. Do you know why it broke the ring or no? Just for peace of mind, I'd do the water pump and rebuild carbs while it's all taken apart. Those 2 things along will probably run $150 in parts, give or take depending on where you buy the parts.

 

[kybodyman]

Re: piston ring replacement

Update, pulled spark plugs. Upper plug on bad cylinder was clean and dry, but lower plug was a little damp with fuel and had a couple of small metallic flakes on it..Not a good sign I would think..