I came across two OS 40 H engines at an estate sale. They are old models without bolt on mufflers. Both are new in the box and the instructions indicate they were "racing engines'. The information material also said they produce the power of a 50 to 55 two stroke. Does anyone have any information regarding these engines? Hate to just let them go. The OS 703 strap on muffler fits so that shouldn't be a noise probles. Thanks for the help.

I have two of these engines. They have ball bearings and I believe they are non-Schunurle ported. They have an old air bleed design carburator and a one ring piston. My engines date to the early 80's.

The claim that the engines have the power of a bigger engine is probably just that, a claim. While it does seem to have plenty of power, the K&B 40 seemed to be about the same as the OS. My engines will turn a 10-6 Master Airscrew prop about 12,700 rpm. I have had some trouble getting a smooth transistion from idle to full speed. This could be due to the air bleed carb.

My LHS says that parts aren't available anymore. I find parts and parts engines on forums and eBay.

let me know if you want to sell one

DerFly,
I would be interested in selling one of the engines. Realize that there is no muffler; however an OS 703 muffler will fit. The engine appears new in the box, complete with instructions. I am open to offers. Please let me know.

Thanks,
Ed

There were at least 3 variants of these. If yours are the racing version they'll be marked as 40P on the transfer port, P was for Pylon. Then there was another marked 40S which was for C/L Stunt and another marked as just 40 which was the normal RC version. I'm not sure but the 40P may have been a twin ball raced crank, the others just use a single ball race at the rear of the crank. Definitely loop scavenged and very nice engines in their day.

I have one of these I put on a Diamond Dust. All up weight was under two pounds. I never tached it, but it goes like stink with a 9x6 prop. It will keep up with a friend's with an OS 46fx, his has higher weight.

Thanks to all that responded to my post.

The information was most beneficial. Since I have two of the engines, I would be interested in selling one of them. Both are new in the box; just old stock.

If anyone is interested, please e-mail me; [email protected]

Thanks again and thank you RC Universe.
Scratch One

MUFFLER IS SOLD> THANKS RCU!

FYI -- i have a complete (no muffler) 40 H for sale, buy it price of $60 includes shipping. engine has good compression, complete and functional carb, good little engine! is posted on e-xxx but will gladly sell to an rcu member directly and remove from EBAY if buyer comes from RCU. will pay donation to RCU for any buyer who advises s/he is an ebay member.