ptulmer

My Feedback: (5)

First thing to come off was the muffler. However, it had a good amount of area and I don't think it was all that restrictive. So after all is said and done, it'll go back on for a test. Removing the carb revealed a pleasant surprise. The plastic carb is separate from the reed holder. Leaving me with only a couple of things to do to get a venturi fitted. But first I gotta figger out how this thing is fitted! Any of you guys pulled one apart before? Is the reed holder threaded, press fit or a slip fit?

ffkiwi

I don't know pt-you raise a really good question-I've just taken my own new unrun one down to the same degree-and I can't remove the carrier either-I can feel a tiny amount of movement, but thats all-I'm guessing that it is a (tight) slip fit into the crankcase rear opening, and that there is some kind of internal ledge or rim within the case that limits the depth the reed carrier projects inside.
My suggestion-make up an expanding mandrel to fit the 5.5mm central hole, and grip by expanding the mandrel and seeing if you can withdeaw that way. I tried gently twisting the carb mount-but that starts gouging out the plastic with the flat on the reed carrier spigot-forunately I discovered this before I did too much damage.
Best of luck-I've often thought that a TD 09 carb assembly would improve things-and the engine takes a standard TD 09 head if you want to go that way.

'ffkiwi'

SGC

PT,
The reed holder just push/pulls in/out, its a very neat fit , it also has a flat gound at the top inside to clear the cylinder base so it cant be rotated, it must be pulled straight out. You may need to unscrew the cylinder befor removeing the reed holder?
Stewart

combatpigg

My Feedback: (3)

If the engines passes a leak down test, then it is worth playing with.

ptulmer

My Feedback: (5)

CP, it appears to be brand new and un-run!

SGC, I bet you're right about the cylinder needing to be removed. It wouldn't take anything more than a bit of distortion to lock it in place.

combatpigg

My Feedback: (3)

Patrick, there are lots of QBs that fall into the "never ran" category. I would do the basic mechanical tests first before investing any time into one of these lemons, at least you will know if you have something to work with. The QB was the only engine that I ever owned that never ran, even after 2 trips down to Cox and back. They just basically lied to me and said that the engine ran fine for them. Until I discovered this forum a few years ago, I had written Cox off 100% except for the remaining TDs that I had laying around.

ptulmer

My Feedback: (5)

Well, it doesn't pass the leak down test as well as I'd like. But I do plan on thinning the piston, which IIRC should expand the piston just enough to need to be lapped back in. Am I on the right track there? Two other things I plan on doing are measuring the porting and venturi on a TD .09 and TD .049, then solve for .074. If everything adds up, fine. If not, modify if possible. Making the new venturi and needle valve should be a real experience!

rainedave

My Feedback: (1)

Interesting project. I passed one of these by at a recent swap meet due to their reputation. Maybe there's a silk purse in there somewhere.

David

combatpigg

My Feedback: (3)

Patrick, I found that you can exert a force with a dull tool that will expand the piston a little. If you can get the cylinder to stay pumped long enough to say, "Cox sucks" 5 times real fast, then you've got a usable piece.

Toad

roflol!

DeviousDave

My first engine was a Queen Bee. Never got it to run until I moved across country to live with my Dad, who was an accomplished RC'er. The problem was that the engine is INCREDIBLY prone to overpriming. Once I got the hang of it, it was an easy to start engine, but woah unto me if I got more than 1/4 drop of fuel down the venturi....

Throttle on these engines works really well. As everyone knows they won't exactly pull stumps out of the ground but it flew my Aerocraft Snapper around well.

ptulmer

My Feedback: (5)

Yep, loosen the cylinder and the reed holder falls out. The reed has what appears to be factory damage and there were aluminum slivers in the crankcase. I'd bet that bad tolerances and sloppy QC killed this engine quicker than bad design.