I have a new BME 50 with pitts muffler. I set the engine up last fall and it ran great, idled reliably around 1600. The first two flying sessions this year it performed great.

Now it won't idle below 2000. Anything under 2000 and it slowing loads up until about 1300 and dies rich. This engine has about half a gallon through it.

Today I spent about 2 hours trying to get a reliable idle. I could close the low end needle down to about a quarter turn and still it would load up. Of course at this level it would hesitate on throttle up. But, it would still load up die.

Any ideas?

What's your oil ratio??

Oil ratio is 40:1. I use the same fuel mix to run two BME 44's and have no problems.

I don't think the carb inlet needle is closing correctly

Are you referring to the low end needle, Hangercat?

If you're sure it's dieing rich, about the only think I could think it might be is some trash in your needle and seat. First I would take the low needle out and blow the port out, clean the needle, and reinstall. If this didn't help, then remove the cover on the carb that has the hole in it to get to the needle and seat. Should be the metal cover. Remove diaphragm and gasket and pay attention to the order they are in. Most the time they come off with cover plate, so that's not a problem. With the cover and diaphragm off, you'll see a small needle and fork held in place with a screw. Remove the screw, and you can take the fork and needle out. But be careful, there is a little spring under the fork. These babies like to disappear real easy! In fact, you can loose them just as easy putting it back together as taking it apart. Very small spring. So clean work bench before you start and expect the worst. Check the needle and seat for garbage.

Thanks, NOGYRO. After replying to Hangercats post, I remembered rebuilding a carb a couple of years ago, and I have already pulled the diaphram cover off, removed the needle, lost the spring 9 times, and the hinge pin 7 times, and checked it out. The seat looks clean and unscratched, the needle show no wear. Incidently, this was done with the carb on the engine, and the engine on the plane. I don't know whether I'm stupid, or just lazy.

I thought about stretching the spring, and then thought better. Probably should just buy a carb kit.

The more I think about the advise you and Hangercat gave me, the more I think it's the inlet needle. When I was trying to set the carb yesterday, after having no success, I went back to factory settings (1 1/4 L - 1 -12 H) and restarted. After that run I had more slop on my plane than a glow engine. I have never seen raw fuel like this on a gasser.

This engine has very little time on it, but it did sit all winter. What do you think? Go for the carb kit?

LOL, man that paints a picture.

Wise choice on not stretching the spring or bending the fork. These things just don't change by themselves....

As far as the carb kit goes, the engine sitting over the winter shouldn't make that much difference. I've got a chainsaw, weed whacker, and leaf blow over 10 years old and still have the original diaphragms in them.... No more than the kit costs, it would be a good place to start...

Normally you have problems with these things going lean, not RICH.

Maybe Ralph will jump in here and have some ideas??

Thanks for pointing me in the right direction guys. I must have unknowingly removed some gum or a particle of some kind when taking the inlet needle out of the carb. I put it back and ran the engine. The slop on the bottom of the Extra is gone, and the idle is much improved. I can hold a steady idle around 1700 to 1900. It's not where I really want to be, but it will do for a few tanks to see if it improves.

While experimenting today, I could hold a 1500 rpm idle for a minute or so, but that nearly shakes the wheelpants off.

If I have any problems, i'll pick up a carb kit.

Great, glad you made some progress. I figured it could be a piece of junk so small you couldn't see it. Probably just removing the needle and wiping it did the trick.....

Thanks for all the help guys. Flew WH Extra Sat.. Good news and bad news. The bad news flame out at 100 ft. alt. 50 yds on the far side of the runway at the mid-point. The good news is that it is a real floater, smooth 3pt landing on the runway.

Changed the carb out from a '44 I had on the shelf. Identical carb. Still had trouble holding a steady rpm at idle. Changed throttle servo, AHA, everything's reliable now. Engine runs great.

QUESTION? I'm having a little trickle of raw fuel dripping from the ventura at 1700 rpm sustained idle. Does this mean I am still too rich on the low needle? Don't want to over-lean an engine, especially a new one.

When I switch to idle-down rpm drops from 2400 to 1700 but there is about a 5 second delay. Does this this tell you anything?

I have tuned a lot of engines and have had satisfactory results, but I think I can learn a few things from you guys.

Thanks in advance,

A little fuel coming out of the carb on a piston ported engine is normal. If you put a velocity stack on it, it helps reduce it. I wouldn't lean the low end to try to get rid of it.

If it takes 5 seconds to drop from 2400 to 1700, sounds like you might be too lean on the low side already. Slow to come back to idle is usually a pretty good indicator of it. Are you sure your servo is responding right? Check it with the hatch off just to make sure. If the servo is acting properly, open the low 1/12th turn and see what happens. You can always put it back.

It means you put the carb back together with the diaphragm installed incorrectly.(most likely)
You should never have fuel dripping/trickling out of the carb.
Remove the diaphragm again and if there is a forked end, place the metal piece between the fork. If there is no fork and the diaphragm just rests on it then you either have a stuck metering needle or bent fulcrum arm.

Thanks guys, i'll try a little richer. Like you said, I can always put it back.

RTK, this carb has never been apart. I took this one off a '44 on the shelf. It's identical, and that engine has always ran great. I still have the one that came with the '50, so I still have to pick up a kit and work on it.

Is the fuel dripping, or spraying out the carb?? Gotta agree with RTK if it's a drip, shouldn't have that. If it's a spray, that's a bit more normal....

I have had 2 carbs come with the diaphragm not placed correctly in the fork.

If it is dripping may be the metering needle is stuck, but dripping is not normal and should never happen. As nogyro said a fine spray is normal but that is not a drip.

If the metering needle is stuck open the carb will keep pumping gas through the carb and cause a dripping, (not drawing normally due to lower pressure in the venturi, but pushing it through) or at least thats what happened to me and that is how I understand these carbs to work.

I'll start it up today and see which best describes the escaping fuel. With the old carb, it was a steady stream, and engine loaded up and died. With this carb the engine is running good, and idles good.