I just reinstalled my RC Ignitions converted G23 in my CG Extra 300, and I am quite impressed with Ralph's work. The exercise reduced the weight of the 10.5 lb. model by 1 lb.

Unfortunately I am having a problem with a somewhat erratic top end, which I do not think has anything to do with the engine work that was done.

With the carb having been rotated and the needles now facing front in the cowl, the prop blast seems to be affecting the carb and causing a loss of rpm. When the carb is partially shielded from the prop blast the engine runs perfectly.

Otherwise, the engine starts easily, is much smoother and vibrates a lot at idle. What should I do.

Try a velocity stack and see how that works out. You may also try placing a cover, aka air deflector, over the hole in the plate the is over the diaphram. Don't block it off though.

High vibration at idle is probably from an unbalanced prop.

A velocity stack might do the trick. The prop slipstream is messing with the mixture. Also, there might be small holes through the carb gasket that you covered or uncovered when you rotated the carb. Check it out.

Dr.1

Had the same problem on my BME 50. Got one of Troy Built models carbon fiber cover plates for the carb. Cleared up my engine. As a quick test, take some managers tape (two faced tape) and put two small pieces on the cover plate but don't block the little hole. Then take a small piece of lite ply and put it on the tape. Fly the plane and if the problem goes away or gets better buy or make a nicer cover. Had another engine that needed both the velocity stack and the cover.

Thanks for the prompt response guys, you all were on the money. I taped a 1/2" sq. of file jacket material to the carb cover, blocking the prop wash from the pulse hole, and walla...no more problem.

All I now need to do is come up with a permanent shroud. If only all my other problems were this easy to solve.

karolh,

Take a look at this thread. I posted a picture of how a lot of us fix the problem. Just solder a fitting to the cover plate and run the hose inside the fuselage.

http://www.rcuniverse.com/forum/m_30...tm.htm#3038501

If you need more info, let me know.

Chuck

chuck l,

I certaintly will adopt your method of a permanent fix for solving my problem. I plan on using a pressure nipple from one of my old glow engine mufflers as the vent fitting. Many thanks.

karoth,

The fix shown in the thread wasn't my idea, it came from somebody else. I just don't want to take credit for the idea.

Chuck

chuck l,

I'm quite sure no harm was done, so nothing to lose any sleep over. Yours or not I'm just thankful that someone pointed me in the right direction. Cheers.