Engine Question
 

Hi, I'm flying for about 2 years now and my engine is running a bit weird sometimes. The engine is a OS MAX .25 of about 20 years old. I could buy it from a friend for $30. He had never used the engine except for running-in. What should be the problem?
Any help is appreciated.

RE: Engine Question
 

I'm not sure what you are asking. Do you own a weird-running OS 25 that is 20 yrs old & your friend also has a just-broken-in one that he will sell you for $30? Or does your friend simply have a 20 yr old just-broken-in OS 25 that he will sell you for $30?

In either case, I think that $30 is too much for a 20 yr old OS 25, just-broken-in or not (unless it has collector value).

I don't think that you will have any particular problems in getting it to start & run, but it is probably a cross-flow design that won't be as powerfull as current engines.

RE: Engine Question
 

That's not the problem. The engine is running fine, but sometimes when it's hot it doesn't run regulary. Wat should be the problem then? It would probably need a refurbish to run smoothly again, but I'm not sure, that's why I'm asking.

RE: Engine Question
 

Is it your engine, or your friend's? If it is yours, try running a slightly richer high-speed needle mixture. If it is your friend's, don't buy it.

RE: Engine Question
 

It's my engine, but if I run the engine richer, the rpm goes down at full throttle. Or is that no problem?

RE: Engine Question
 

Tweak it to max and back off about three to 5 clicks. I would also check the bleed air screw setting as this can change when it gets really warm or cold meaning it may need to be readjusted. A clogged bleed air hole can cause erratic running in these older engines

RE: Engine Question
 

Thanks for the information, gonna try this tonight;)