Thread: 1998 50hp evinrude outboard

I would never replace just one piston. It is a matter of balance. Bore a cylinder and put in a bigger piston and it will weigh more than the stock piston. You could pull the stock piston and have it weight matched to the new one but you will be $ and time ahead to just bore both cylinders and replace both pistons.

I would replace the rings in the second cylinder there may be carbon build up in the piston ring lands. More then likely this is the reason for the ring breaking. How deep are the scratches and how much do you want to spend, Not saying it is the perfect thing to do but if they are not too deep maybe they can be honed out. Some of those early outboards were bad for carboning up the rings especially if cheap 2 cycle oil was used in them.

the only scratch is at the exaust port bottom side very shallow only goes up toward the top end about 1/2 inch the rest of the wall of that cyl.is very good not even any ridge on either top or bottom cyl walls consider honing out the bottom one that had the problem,and replacing both sets of rings top and bottom. Replacing the bottom piston with another new one and putting it back together.thinking maybe touching up the upper cyl. with the honeing while i have it but just enough to get rid of the glaze will that work...

I have replaced one piston many times even on a V-6 outboard but never, never use old rings and always have the other cylinder honed to check for straightness, if the other is straight , clean old piston ring lands, I mean clean, spotless and use new rings on the old piston

I am going to replace the rings on both pistons,about 25.00 per piston,and about 55.00 for the new one.will hone both holes but thats where im confused at and I cant afford to be confused when I start.If I hone each hole are there enough ring expansion to take up the removed space between the cyl wall and piston.But I dont think I can go too far just honning the cyl.s will go slow and keep checking my work.....specs on that engine might have a max distance from piston to cyl wall....thanks you guys are a lot of help...Jerry

Usually with a hone you are not going to take very much material off the walls. Be sure to use enough oil to keep the hone working properly and try your best to keep a 45 degree cross hatch pattern when finished honing, this will help your new rings seat properly.

was able to remove the powerhead from the engine friday,was not as hard as i thought it would be.Today after much furstration and persuation.removed the flywheel. picked up a puller from oreillies.had to use a propane torch and some cubes of ice but got it off was so afraid i burnt something up but every thing was Ok.Got the case apart this evening also but didnt remove crank or piston yet. Will do that after ordering my parts.trying to locate tourqe specs. but cannot find them in this book I got from the library.also reading up on end gap for the new rings,they must be with-in specs.or you could blow a piston if the motor got hot and the ring gap was not enough,it would hang on the exaust port or intake port.I think that could have happened to this engine before..the engine got hot.
If any one has the torque specs on a 98 E50TSPLCC evinrude I would be very grateful...Boy am I having fun....Im watching all youtube
videos of how to rebuild evinrude powerhead,that I can find and searching the web for part numbers for what I need.thanks guys for you answers to my questions ...Jerry

I have an older 'rude and a Clymer shop manual for it, sorry it only goes to '90, mines an '80 100HP, but if you have one of these books if it's like mine you'll find all the engine torques listed in the power head section. in my book it's on page 369 I don't think I'd use the ones listed in my book on a model that much newer than mine, but maybe this will give you a place to look if you can find the same book that covers newer models than mine does. Good Luck