Re: Piston Rings for a OMC 5.5
Sixty to sixty-five pounds is about what I would expect to see from a small, rope start motor. The split in values, is also right under the 10% differential value, that is typically used to determine overall health of the cylinders. I don't think that I would re-ring the motor, at this point.
If the motor was submerged and not properly dealt with later, I would expect more problems than you are seeing. That is not to say that this might not have happened, but I am not hearing anything that gives me huge concern about it.
The gear case is something else. If there is water and sand in it, that's not a good thing. If it is just dirty in appearance (no gritty feel, no milkiness, etc.), I would go ahead and replace it. Don't forget to get new plastic crush washers for the drain and vent screws - failure to replace them is the most common reason why water gets in gearcases.
If the carb was properly cleaned and rebuilt, but the motor still doesn't run well, its a pretty good bet that the ignition system needs attention. The good news is that it isn't terribly expensive to replace all of it. At a minimum. I would most likely replace the points and condensors. Don't try to file the points - if they are pitted, replace them. If the coils show signs of cracking, replace them too. Bear in mind, however, that even coils that don't look bad, can be bad. If in doubt, take them to your local BRP/Evinrude dealer - they can test them for you.
One easy way to do a check of the ignition system, is to use either a spark checker (available at most auto parts stores) or an inductive timing light, to see if you are getting current to the plugs. When you set the new points, you must set them exactly at the peak of the cam lobe. There should be a mark on it, to tell you where that is. The recommeded setting is .020, though I've heard of some people setting them at .018. I stick with the factory recommendation.
As for the gasket, yes, there is one that goes between the top of the midsection and the bottom of the powerhead. It is highly unlikely that you will be able to successfully reinstall without replacement, so buy one.
IMO, the 5.5 - 6 hp series was among the best group of motors that OMC ever made. Short of major abuse, they tend to run "forever." I even used a '56 5.5 hp Johnson that I still own, to push a 26 foot sailboat for awhile. The motor that I normally used, was being rebuilt and I needed something for an auxilliary, so I had the 5.5 converted to a long shaft and used it. The old Johnny got the job done!
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