doubledee

My Feedback: (4)

OK, here's the deal. I bought an OS 120 Surpass 1 with a pump on it. I can't get it to run right and everyone tells me that I never will because that particular engine was a dud.
If anyone has a tip on how to make it stay in tune I would appreciate it.

If worse comes to worst, is there a way to remove the pump, get a new pack plate and use it as a standard 4-stroke w/o pump?

Comments and advice are appreciated.

Thanks,

doubledee

IscarRep

My Feedback: (8)

Hey Double,
I have one of those and it runs like a raped ape.As far as dumping the pump that gets expensive.I read about doing that and I believe you have problems with the rear support of the crank when you do that.I think it has to do with the pocket in the back plate that holds the bearing.The reason I read this is I had that motor laying around for 3-4 years in a box after it was pulled out of the plane that I sold. When I stuffed it in something else it just wouldn't run well until I changed the plug.I was thinking of doing the same thing you are talking about until I got mine squared away.Mine is very sensitive to lo speed adjustment so watch that.All I have to say is when it's right it is a blast to have in a plane.

IscarRep

Bax

My Feedback: (11)

If the pump's OK, here's how to set up the mixture:

http://www.osengines.com/faq/faq-pumped.html

LuvBipes

My Feedback: (4)

Bax, a friend has one that's on its second or third set of bearing (must be 10 yrs old) and runs great. My friend did mention, however, that in order to get it to run right he had to use a T-fitting somewhere in the plumbing to bleed off excess fuel pressure. I also recall a similar discussion in these forums around last year, so a search might provide the answere

jimcork1

My Feedback: (4)

I had the same engine and after about 30 flights the pump went out and OS had no replacement parts. They continued telling me that my pump was out and it would be 30 days for parts. After 4 months they sent me a note and told me suddenly that my engine was totally bad and for $$ they would replace it. I did replace the pump motor with one w/o pump,, good decision on my part.

If the pump is bad you could check part # and replace parts with non pumped motor parts. Good luck. I won't buy another OS pump pump motor due to the poor parts supply and pump failures. This doesn't mean it is a bad motor,, but only reflected in that I prefer to buy nonpumped motors that have parts available.

doubledee

My Feedback: (4)

jimcork1,

I know what you mean about not having a source for replacement parts. The pump for this motor is no longer available. It seems that OS Engines never fixes a problem on a current model, they simply make modifications and come out with an incompatible new model.

I hope it isn't the pump. I have recieved a lot of good advice on tuning it and we'll see if it will tune out and run right. Incidently, the pump appears to be working.