I am having a problem with the carb settings on my BME 115. When I set the needles for a good transition after a 30 second warm up. I cannot fly in a knife edge from right to left only, left to right is o.k. This is at half throttle or less. Above half throttle is o.k. I can fix it by leaning the low end but then it is too lean for a good transition. If I hold the plane on the ground in this same atttitude with the cowl off, fuel comes out of the carb and the engine smokes so I know it is going rich. I have tried a line of the carb plate to the fuse, and a 3W 90 degree intake. I can't see it being an airflow issue if it is doing on the ground with the cowl off.

Besides having a bad or gunked up carb,,,,,,,, you might be to rich on the high needle. With BME's the high seems to have more of an influence on the lower ranges of throttle settings than some other engines. I try to keep my low lean and adjust the high by how it flies in the air.
I still have a theory about the WGA carbs and there built in rev limiter, but have not yet spent the time to prove or disprove it.

The rev limiter is just a ball and spring that opens at HIGH rpm...Your engine won't run fast enough to make it work unless the prop comes off...You could take the screw out and plug the hole with a small piece of solder...the screw is REALLY tight in the carb body..
I don't know how fuel can come out of a correctly set carb on a reed valve engine....
Check the inlet diaphragm, maybe the piece in the center is not in the fork in the lever...
The diaphargm should be on top of the gasket.....

good scoop

Ralph I took out that screw recently and found that little ball does not have very much pressure from the spring holding it put. That is what made me wonder if a little shaking could un-seat it. Especially due to the engine pulses running in line with the ball.

I don't know what the rpm would be, must be over 10,000 at least...

dbcaster-- How long are your standoffs and/or do you have a lite constructed motor box?? I am just trying to get an idea of your set-up and compare it with what I have and have experienced.

I have to bow to your experience and expertise Ralph, but I am still sticking to my un-seating ball or rich mixture theory Had a drippy carb once that was cleaned and rebuilt more than once. Still dripped for some reason at the low rpm band. We spent a good 30+ minutes on the phone going thru that one and nothing made any sense that you or I came up with. Wish I had more time to delve into testing my theory.

RTK
were u never able to stop the carb from dripping?

Took it off and replaced it. So far no dripping. Have only flown it a couple of times so far. I also boxed in my 4 inch standoffs so maybe that helped, don't really know, change two variables at once so there is no way of telling which one was wrong.

That is why I was asking dbcaster those questions. Might help solidify my crazy theory or blow it out of the water[]

Pretty much, but it was long after the problem started. He's using some pretty long standoffs on his Sukhoi. He tied them together in some manner and most of the leaking went away. My hunch is that the carb was getting beat to death from power pulses and the long standoffs. Sorta like cracking a whip.

Don't know for sure that was it, and if it was if any long term problems were created in the process.

I am using oak blocks for stand-offs that are very sturdy. The fork is in the diaphram and I did check the pop off and it is good. The only time fuel comes out of the carb is when it is at a 45 degree angle with the needles pointing towards the ground. As soon as I put it back level the rpms come up and the fuel drip goes away. I have the high needle set for just rich of max rpm and the low just above stumbling on transition warm.

Forgot you finally changed it out. The two times we flew you still had the wet one on it.

Have you called Keith yet?? I bet he would have a solution to your carb situation.
I don't think it is fuel puddling because more people would have mentioned this. My 115 does not seem to suffer those symptoms in flight, at least at the speeds I fly knife edges at.

dbcaster, one more question. It does not relate to the dripping, but the run-ability of all engines. How much clearance do you have between the cowl and the bottom of the carb? Too little space can cause problems and so can air flow changes over the carb venturi opening, not only the diaphragm, but the venturi opening too, or at least I have seemed to notice this with certain installations.

I have talked to Keith and he thought it was airflow. I tried the 3W intake with the hose from the carb plate to the intake. When I installed it I had to cut a large section of the cowl out for it to fit so clearance is not an issue. There is another person with a 115 at our club and he does not have this particular problem so I agree that it is not puddling. I will talk to Keith tomorrow about a new carb.

Petaluma is not that far, we will have to get together and fly sometime. I PM'd you, give that a try first and see

dbcaster
did you get all corrected on this issue?

I have the new carb now. I flew seven flights on Friday, getting better on each one. I was rich on the high so I had a bit of loading in knife edge but no where near as bad as it was. I have leaned the high were it should be now so I think all will be well. It is blowing about 30mph now so I may head to the slope instead of the flying field. I should be running it again on Wednesday. One thing I did find out is, the needle settings are different on the new carb. I know they will vary from carb to carb, but right now I am at 1 5/8 on the low and 1 on the high. I started at the settings on the old carb so that is why my high was so rich.

good deal i will let u know how mine runs when i get my ignition back, it should be this week. What prop r u running. I will be tring a Vess 27A.

You may need to change that 27A out pretty quickly. I have 5 gallons through mine now and I am running a Menz S 28x10 turning 6100 rpms. That 27A will rip like crazy

dbcaster
wow sounds like a beast i need to avoid steriod testing on her she may be dirty

I was going to fly the new block and carb, but as dbcaster mentioned, it's blowing hard out there. So I ran it instead, All seems well. The high end needle seems more positive and consistent.
Once I fixed my cowl air flow problems on my original carb and block things ran fine, so I expect this to also.