"Rebuilt" an MS290... now NO idle...? Am I thinking right? HELP

[blsnelling]

One very important thing here. Did you remove ALL transfered aluminum? That's a must. Any that you leave is a raised surface and will promoted another seizure. Scratches in the lining will only hurt compression since it's a recess. So the important thing is to make sure all transfered aluminum is gone. If you're not sure, tear it back down before you run it again.

 

[brages]

I'm kind of thinking I'll let it go and see what happens. I spent enough time trying to get the cylinder clean, with the muriatic and with sandpaper. I think I got off all the transferred aluminum, just left a few small, but smoothed out, grooves.

If the scoring is hurting the compression, it still starts easy and idles smooth.

I don't really care to mess with the cylinder any more... At this point, I'm ready to send it back to my brother-in-law and see how long it lasts. Worst case, if it lunches itself, maybe Bailey's will have their 390 piston/cylinder upgrade available by then... what have I got to lose - a $30 piston and a scored OEM cylinder?

 

[Saw Dr.]

Run it! Get it warm, make a few cuts, then stop and pull the muffler. The exhaust side always scores the worst. If there is any aluminum piling up on the ring edges, it won't last long. If there is not, run it like you stole it!