Originally Posted by Chotu
1. Is this Outboard salvageable? 2. What are my steps? 3. Do I need to just immediately replace the cylinder? 4. And rings?
5. Do I need to replace the piston? 6. Do I need specialized tools like a micrometer to measure for any warpage? 7. Or are there some tips and tricks to doing this?
1. Yes it is salvageable, as long as your don't run it more and do further damage.
2. First buy a repair manual for that specific engine. The steps are spelled out there.
3. No. The repair manual will give wear limits, out-of-round specs, etc. Some engines cannot be rebored, but most can. If the cylinders are in bad shape reboring is the usual fix. Then a larger piston/ring assemblies are installed. Ordinarily you would also replace the rod bearings st this time. But in any case the engine should be completely disassembled, and all parts
checked for wear.
4. Rings, for sure, need to be replaced. Installing oversized rings is not a good practice, without reboring the cylinders and fitting an oversized pistons.
5. Pistons -- almost certainly, after a seizure. But the measurements will determine this. Very minor scuffing can be buffed off, but if you leave a high spot (high by about a hair's thickness, the engine may seize again.
6. Yes, you need to be able to measure accurately down to .001 inch or .01 mm. If you are skilled, you can use telescoping gauges for internal measurements, but otherwise a bore gauge or internal mics must be used. For outside measurements, a good set of vernier calipers can be use in a pinch, but outside mics is the standard. If you don't have your own, you can probably find someone to do the measurements for you. (e.g. a machine shop)
7. There are shade tree mechanic
shortcuts, but for a small engine, why not do it right? Get the manual and follow it. You'll need a set of wrenches, and a good small torque wrench (3/8" drive), a full gasket
set, etc. You should be scrupulously clean when your put the engine back together; prelube everything, prefill the oil pump. While you are doing all this, also replace the water pump
impeller, check the lower unit oil level, etc. Probably a good idea to rebuild
the carb, because running lean is a good cause for overheating