timrcpilot

My Feedback: (6)

I have the same problem on my OS 18 tm as seen in a previous post. Engine was purchased late in the season last year, probably has about 3 gallons of fuel through it.

The one-way bearing (roller bearing) is slipping on the starter shaft.

I pulled and cleaned the one-way bearing (roller bearing) but noticed an excessive amount of oil in the bearing area, starter gears, etc.
Cleaned everything removed all oil. This worked for a couple tanks of fuel, then the same thing happened. The one-way bearing was slipping and not turning the engine over. Took the starter assembly off the engine , again, lots of oil everywhere. Cleaned again, replaced one-way bearing (roller bearing) with brand new one (still thinking the problem was in the one-way bearing). I had previously replaced the one way bearing about a month ago, as it failed and came apart when I removed it.

4 tanks of fuel later, same problem, new bearing slipping, excessive oil in the bearing area and in the starter gears. The starter shaft has some play (does not seem excessive) as it passes through the bushing in the back plate.

It would appear the pressure from the crankcase is forcing oil/fuel into the bearing and starter gears.

How do I remedy this problem?

I love this engine, power is great, does not require much adjustment on needle valves. I own six OS engines in my airplanes, but this has me puzzled.

Thanks,


Tim

Bax

My Feedback: (11)

Oil will be forced along the starter shaft from inside the engine. That's what's going to happen with that kind of engine. The shaft is supported on a bushing, which needs the oil for lubrication. Cleaning is a way of life.

timrcpilot

My Feedback: (6)

I wouldn't mind cleaning after a gallon of fuel, but after 3-4 tanks, that is not realistic. Typically when we run in an afternoon we may go through 8-10 tanks, to pull the engine and starter after 30 minutes of run time will not win many fans. I love my OS engines but this amount of oil is truly excessive.

The first few gallons of fuel did not generate this kind of problem.

Why is it so excessive now?

Thanks for your help,

Tim

jeffmiz

Same Problem here Good engine but bearing keeps slippin'

catbutt

I have this problem with mine, but much worse, it occurs after ANY run, long or short, even less than 1 tank. Check the bushing in the backplate, likely the output shaft has play in it's fit in the bushing. This allows more oil/fuel to run down the shaft and into the bearing. Ideally it should have no play and fit snug. If you can move it side to side or up and down at all then either the shaft or bushing is worn down, or both. You might try to replace the backplate and output shaft as well, perhaps this might solve your problem, as it worked fine for 3 gallons. I have tried this with my 2 month old OS 18 CV-RX, unfortunately it has not fixed my issue, but my leak seems worse than yours. Yours may have just worn from use. Hope this helps you some.