How do you prevent damage to an engine when starting it after it has set for years with out being started? It’s a snowmobile engine. Gas & oil mixed.
Take out the plugs and add some oil or diesel fuel to the cylinders. Let it set for awhile so it can free up the rust or carbon deposits. Don’t fill up the cylinders, add just enough to rest on the pistions. Then crank er’ up and go!
And with the bearings, make sure you got oil going through the lines if injected. If it’s just a mix, that should not damage the bearings when properly mixed.
This faintly reminds me of the “pull-through” required of old piston aircraft engines. They’d turn off the magneto (i.e. disable the spark plugs) and turn the propeller manually a few times. This got the oil flowing.
I don’t know the details of the engine in question, but it seems to me that if you removed the spark plugs and squirted some oil into the cylinders, and manually cranked it (with the spark plugs still out, for various reasons that I hope are obvious), you could at least do some good to the rings and cylinder walls.
It matters a LOT if we’re talking about a two-stroke or four-stroke engine. You didn’t say what kind it was. If we’re talking about a four-stroke, it needs an oil pump to (among other things) keep the tappets lubricated, and I don’t know if manual cranking would generate sufficient pressure to do the job right.
The more I think about it, the more I think that you should consult a professional mechanic before firing the sucker up. I’ve stated my opinions, but to be honest, the last time I fixed a motorcycle engine, I sheered off one of the bolts that held the head. Getting it out was so hard that, yes, I had to turn to a pro for help.
Are you educated, erudite and maybe a bit eccentric?
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Squirting a little bit of light weight oil thru the sparkplug hole is the correct way to free up an engine that has siezed up from sitting unstarted too long.
If the engine was parked with fuel in the carb and lines they will have to be taken apart and cleaned because when gasoline evaporates it leaves gummy varnish deposits behind that clog the small ports and jets in the carb.
Gumout brand carberator cleaner works well for this.
I have restored several large 2-stroke motorcycle and outboard marine engines useing these tricks.
Also after you remove the carb spray WD-40 into the open intake as the pull rope is pulled slowly,that will help prelube the bearings on a non-oil injection type moter(gas and oil premixed in the gas tank).
The Pulling thru of radial aircraft engines is to clear out the oil that has drained into the lower cylnders when the motor is not running.
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