Thanks for the tip.

After trying again this weekend with the same results, I'm about to remove the entire engine, tank, and fuel line system and start over again with something else.

Silversurfer

Is your tank mounted on the CG- or behind the firewall? Maybe the engine is having a hard time pulling fuel from a CG mounted tank set-up?

You stated that you are not the original owner of this engine.

Maybe it was not broken in properly.

If it got hot during break-in; then it might be ruined. I've seen a few guys do it. I ruined an OS 120 Surpass this way. After an engine gets too hot during break-in; it will never run right. It will heat up after a few minutes and start to sag and loose RPM's. Then it quits.

Maybe a new piston, ring, and cylinder will bring new life to it; if all else fails.

Just a few ideas for the stew.

I inspected the engine, inside and out, after I picked it up. It appeared that it had been run for one tank of fuel, or less. No burning, scuffs, or other potential damage was noted. Bearings had no rust. Engine seemed to be well taken care of.

Fuel tank is located approximately 1 1/4" behind back plate of engine. Center line of tank is less than 1/4" below fuel pick up at carb. I have replaced every gasket and "o" ring in the engine with OEM new.

Clunk in fuel tank drilled out as much as possible to accomodate large inside diameter of fuel line. No line restrictions, anywhere.

OS #8 plug. New and previously unused. This is the second of same type plug. Plug not the problem.

Cool Power 10% fuel. Castor,synthetic mix.

Bisson Pitts muffler. Have already tried plugging one exhaust tube with dissapointing results.

I've been building and flying for over 30 years, and I have only had a serious problem with one other engine, an OS 1.20 Surpass II back in the early 80's.

I starting to believe that what I have got here is a good weight for deep water rock cod fishing.

Silversurfer

Try a different carb...maybe that one is bad. It does not have to be same brand. Good Luck C.J.

Did you try an OS "F" plug yet?

Sell me the engine if you want to use it as a boat anchor. I have had a couple of these motors and they run great. There is some problem that is being overlooked. It is hard to find by just words.

If you want to sell the engine shoot me an e-mail.

Give Gary Connely (perry carbs and such) a phone call. sounds like carb is leaking air in from maybe the carb barrle. i haev hnad similar problems,purchased perry carbs from for two of my engines that have cured ailments that no other cures were able to resolve. also try to contact him at www.perrypumps.com
Gary Smith

Silver: Try a different carb. Make a adapter to run a small walbro carb......it has its own pump. A lot of good benifits there. Or get that cline regulator. Do anything besides wasting time with the carb you got. Try any carb that is about the right size for that displacement. Good Luck Capitnjohn.

Thanks Captn. My local hobby dealer suspects that Tower shipped me an "O" ring kit for the wrong BGX engine. 1.08 instead of 2.18. I recall that the parts/engines description on the seal kit did not seem right to me when it arrived.

He's going to re-order the part for me and we will try again. I've never been beat by an engine yet, and I'm not quite ready to give up on this one. Frustrated, you bet, but I'll fly my gasser while I'm getting this one straightened out.

Silversurfer

I converted mine to Electronic ignition with a Walbro carb and the head tapped to 10 mm for a CM-6 plug. Hand starts even in cold winters, 25 min on 16oz of gas, had over 100 hrs on this set-up. I recall the OPS 30 came with a pumper carb set up for alcohol.

To all who replied with their great advice, I finally seem to have it running right.

I removed the fuel tank and installed a larger Dubro clunk. Removed the carb and added silicone gasket seal over the carb base o-ring, and replaced the needle valve o-ring for the third time. It now runs great, but the carb barrel will not completely close for engine shut down. Considering that there is no throttle stop screw on the 8AA carb, it seems kind of odd.

Thanks again to all who replied, your help and kindness are appreciated.

Silversurfer

Silver,don't stop now.I have a BGX-1 0n a Giant Knife.I went through all kinds of problems also.First,it takes forever to break in.After a few gallons,the motor will increase in power every time you fly it.Also you may think you have solved the problem but hanging on the prop close to the ground it will quit occasionally(I know) if you don't get a cline regulator(not the pump!)The problem is fuel draw.This is a great motor once broken in and the fuel draw solved.I almost hate to mention spending more money,but I ran across a header and pipe(about 10") at a steal at Joe Nall and it really added power overall.It is big and OK on something like a Knife but would be hard to install on a bipe or normal plane.Good luck. Dave

Surfer,

If the throttle won't close fully, very likely the idle needle's too lean. If it's turned in too far, it will preven the carb from closing fully. It will also cause problems with high-speed fuel flow.

We start out with the idle mixture so rich the engine just will not idle. You find that a 5mm gap between the needle and the nozzle when the engine's at full throttle will give you a super-rich idle..so much that the enigne won't idle. That's what we want.

Start the engine at part throttle, leave the battery attached, and open the throttle to full. Lean to just rich of peak RPM. Remove the glow plug battery.

Retard the throttle and start to lean the idle mixture, keeping the egine running smoothly. Since we know it's too rich, we know it MUST be leaned.

Eventually, you should reach a compromise setting between the idle mixture and the idle RPM that will give you a good idle and a good acceleration.

Hope this helps you.