Ring Time

[andrew j cox]

So the F50 Yamster Ive been working on failed it’s comp test after head gasket, at least she’s not blowing comp into the water passages she’s holding 70 psi on 2,3 The others 1,4 are holding 125 psi, So I’m assuming she’s sucked the rings in when she was running hot, means now I have split the case, head off again , pistons out and hone the bores and try again, I’m assuming this is straight forward? Any traps?

 

[andrew j cox]

Any old tricks worth trying to unstick the rings? It’s not likely to just behave itself? Course it won’t damn Yammys

 

[andrew j cox]

Compression on cyl 3 has come back up to 125 psi that’s without oil, I did number 2 with a bit of light oil she come upto 100 , being 4 stroke with a proper oil system the cylinders would be a lil bit wetter then they were with head off, plus the throttles closed while doing the test, might it be with some good quality new oil, it’s empty now, with proper functioning cooling system this thing might cure itself or am I clutching at endless straws

 

[andrew j cox]

Additives in 4 Stroke Outboards

Can additives be run in 4 stroke Outboards as they have a oil system of sorts, what I’m wondering is can I run a oil system flush in a Yammy F50? Hoping to unstick a compression ring after the engine was run excessively hot, stuffing the head gasket, she was putting compression into the water both cyls 2 and 3 so I’ve sorted the cooling issues, main water feeds to block n head jammed solid with almost cement like crud, compression test after head done 2 and 3 holding 70 psi but tonite I did comp again and no3 has come upto 125psi same as 1 and 4, I put some wd40 into no2 it come upto to 100, I’m hoping the rings in no2 will come good, not my engine I care for my chrysler in an almost fastidious way.

 

[Scott Danforth]

something like ring-free? have at it

 

[ahicks]

Agree with Scott. Yamaha actually sells a product called ring free or something similar. Pontoon boat engines that are run at an idle almost exclusively are the ones that may benefit the most.

 

[GA_Boater]

Overheat, huh? What do the cylinder walls and piston look like? Ring Free works on carbon and no additive will fix metal jamming the rings or worn walls and pistons.

If the parts look OK, for for it.

 

[GA_Boater]

Both threads were merged. Please stick to one thread for complete history and advice. Thanks.

 

[Silvertip]

An overheat does not "stick" rings unless piston ring lands begin to melt trapping debris and thus the rings. Overheating generally takes the tension out of the rings. It is that tension plus compressing from ignition that holds them against the cylinder walls creating the needed seal. No mechanic in a bottle will fix a burn-down.