Situation: I have a US41 that is nelatively new and ran just great until I changed the carb. The original carb did not have a choke.

The plane will not run. If I choke it GOOD, it will start and only run at high rpm settings. It will die at or above 4000 rpm. the new carb is a Q42-52 hop up carb sold by B & B. It is exactly the same design as the stock carb except for a choke and different jetting I guess.

My engine has the black plastic spacer plate with the 180 degree channel that allows the carb to be mount either side up. I have mounted it exactly like the stock one. All holes and channels line up, good fuel flow, no air leaks I can find. It just will not start as easily as it should, and when it does start will not run below 4000-4500 rpm. When it gets down around 4000-4500 it will start to surge a little then die.

B & B has tried to help, but I'm not getting anywhere. Does anyone have any idea whats wrong. thanks

It's hard to believe Dick can't help you resolve your problem, he's a very knowledgeable when it comes to gas engines. My only suggestion is, it sounds like something has to be plugged in the idle circuit. I'm sure Dick advised you on initial settings? I start at 2 turns out on idle, and if it runs on the high side you probably have that one set right.

Sorry, I can't say this is the problem,

Dale

Something is plugged or covered up. Check that both the choke and throttle plates are installed correctly. I forgot which way was which but likley RCIGN will pop up here sooner or later.

Yes, he has been helping; but I ran out of time (he has to go home sometime). I have it set at his recommneded 2 out on low and 1 out on hi. We have checked all the plate and shaft positions against a carb at his shop. Everything is as it should be.

I'm wonder if it is a pump problem. Guess it can happen on a new carb.

For reference, the throttle plate is on the engine side of the shaft, the retaining screw is on the engine (outer) side of the carb, the choke has not been played with at all; the little notch in the throttle plate is on the side of the carb with the 4 screw cover over the diaphram. the throttle plate is also mounted with the part numbers on the engine (outer) side of the plate.

I have checked all the little holes and channels best I can, they all seem lined up and open.

So open the needles 4 turns and see if you can make it run rich, or even at all. If it won't run 4 turns open then some thing is pluging the jets.

TKG, it will run; it just won't run below 4500 rpm. I'm probably going to take it apart after I talk to B&B again thismorning.



Well, Ive given up and shipped the whole d___ thing off to B & B. don't want to talk about it anymore.

Splais:
I had a US 41 set up with the WA#144 carb.. Through 20-25 flights,it ran beautifully, and I was very pleased with the performance....While flying straight and level, the front broke off the crankshaft, and the flywheel, prop hub, custom 18-12 prop, and a 5"spinner sailed into 80 acres of corn..An expert pilot got the plane down with repairable damage... I called B&B, and all his conversation concerned how much it would cost to repair it.. About $160.00 + S&H.. I returned the cylinder with the broken crank for his evaluation, noting his responsibility as a vendor of the product. This incident involved no dereliction on my part, leaving only metal fatigue as a cause.....After three weeks, I have not recieved as much as a courtesy phone call..I certainly hope you have better luck than I....