Hey guys, I am fairly new to Gas engines. I have a H9 1/3rd scale CAP232 that I put a Brison 4.8 on. I bought the engine slightly used. It has CH ignition with SyncroSpark. On the ground the engine sounds good, even at full power. However in the air on verticals, it misses like you are turning the ignition on and off briefly. I have adjusted the carb to peek and then backed it up about 1/8 turn to the rich side and no change. I have added the mod on the carb to cary the vent hole into the fuselage. I have added the baffles in the cowling. Any ideas?

I am thinking about changing the plugs (although it would seem that if they were going to miss the will miss on the ground at full throttle).

I am thinking about replacing the switch for the ignition battery and even thinking about changing the ignition battery.

What else, sell it and get a DA or 3W?

Send it back to Brison and see if they can fix it?

It also sounds ruff at midrange, I don't know if that is normal or not. I have heard some other engines sound like that?

any Ideas would be apreciated


Thanks,
Ernie Hughes

We recently had the same problem with a 3w to the point where the engine stopped after coughing in the vertical. It ended up being a rich low end keep leaning the bottom end until it wont transition then just richen it up until it will. Then check your high end. Remember the engine always draws fuel from the low end and the high only supplements this as the venturi effect gets greater. Try this anyway it may or may not be your problem but sound very similar.

I thought I beat the carb ajustment to death, but I didn't try it just like you discribed. Also, it is hard to adjust, since I can't adjust it while it is running. So I have to adjust it a little and then crank, run and shut off to adjust a little more. I wander if you can turn the carb around so the adjustment screws are in the rear, then I could adjust it while it is running.

Thanks for your input, I appreciate all of the help I can get. It seems like glow engines are a little easier to adjust. But I am finally out of glow except for my heli.


Thanks,
Ernie

While a lot of people don't like them, I have fixed my airborne only problems with velocity stacks. What I find is that as I fly, the air going past the carb sucks the fuel out of the engine. (you can see this residue when you land). The stack eliminates this.

I am recommending that you try what gangameigs said. It sounds like it is rich on the top to me. These engines are fairly sensitive on the needles. I don't think you can turn the carb around because of the vacuumed hole for the pumping carb. I hope this helps.