newbie-- problem with a Cox R/C Queen Bee

I have a Cox Queen Bee .074 engine i bought new in 94. I bought it for an airboat i was building. I never had the engine running right, now i want to try again. I took the whole thing apart twice, and cleaned it thoroughly, new glow plugs, new battery and i cant get it to run for more than 5 min. now, i cant even get it to start. it doesn't seem to be getting fuel. i can prime it through the exhaust and it will run for a short burst, but i cant get it to run via the carb. I have checked everything- needle valve, reed valve, throttle positioning... i dont know what else to try... should i just give up on it and buy something else? thanx,

I have a Cox Queen Bee .074 engine i bought new in 94. I bought it for an airboat i was building. I never had the engine running right, now i want to try again. I took the whole thing apart twice, and cleaned it thoroughly, new glow plugs, new battery and i cant get it to run for more than 5 min. now, i cant even get it to start. it doesn't seem to be getting fuel. i can prime it through the exhaust and it will run for a short burst, but i cant get it to run via the carb. I have checked everything- needle valve, reed valve, throttle positioning... i dont know what else to try... should i just give up on it and buy something else? thanx,

Which prop are you using? QB Seems larger than 049-051 Coxes, but I found out that I cannot get mine running on anything larger than 6*4.

-Tapio-

For starters:

What fuel?

What prop?

Tank size, location, fuel tubing size?

If you blow through the fuel line towards the carb, does air flow out the spray bar?

The QB was not one of Cox's best efforts, but it can be made to run unless soemthng is way amiss.

Mike D.

As to fuel, it likes high nitro fuel, like Cox fuel. There is a prop from COX made for the Queen Bee. I think it is a 7x3.5 or a 6x3.5. It seems to work well enough. Overall the engine does work OK. bill

Yeah, it works okay. I just wouldn't rave about it.

The 7-3.5 (sheesh, I think it's 3.5 pitch..or is it 3?..memory help me!) has been around long before the QB, originally meant for their .09's. FAI free flighter's used to put them on hot .15's until enough of them flew apart and that practice stopped. Bartels (sp?) made a glass/epoxy copy of it that was one of the de rigeur prop choices for .15 FF for a while, this is quite a while ago mind you. Got one somewhere in my collection.

I would think of the QB as a big bore .049 and avoid any more load than a

7-3 or 7-3.5 myself, as I have yet to see the Cox engine that does not benefit from letting it wind up. 6-4 is a decent choice for this motor, that and a 7-3 are likely similar in load factor. 6-3 may be good choice too depending on application. They're quite happy at 17-18k rpm. And of course I have yet to see a small engine, esp. Cox, that does not get happier the more nitro you give it. 15% minimum for this one, 25% better. Not 100% synthetic oil either. It's been a little over a decade since I had one, I ended up giving it to a buddy as I lost interest in it and bought an Enya CX .11 instead.

Wonder what problem his motor actually has? Hard to help without more info.