Ok I've licked my problem with my carbureter and now I am very dissapointed with the power of my BME 50 engine the motor has a Mejzlick 22x8 prop on it and it only turns 6500 rpm on the ground and after running it on the ground a little a full throttle it begins to sag down to 6300 rpm. I shut the motor off and noticed it was overheating. My paint on the top of my cowling is starting to bubble up.

This is not good at all. I am very disappointed with this engine as every one else seems to be getting much better power out of their engines. I have a little over a gallon of 40:1 Lawnboy through it. I can richen the high end but that puts me at 6300 as a top rpm this sucks.

Remove your cowl. You may not have enough air entering the cowl to cool the engine. If your engine rpm comes up, then enlarge your opening.

I'll try removing the cowling but I can't fly like that until I divert the propwash to the air hole on the carb. I guess I expected more out of the engine than I going to get. Oh well.

As far as cutting up the cowl I hope your talking exit holes cause the engine already has four fins exposed on the bottom.

Yuo should remove the colw to check and see if you can get more RPM and get the engien adjusted. I would recommend that all the fins are in the airflow and not just 4!

Cowling is now off and I soldered a tube on the carburetor hole. So now I can fly without the cowling. It just started to rain so I'll have to wait till tomorrow for numbers on the ground.

Something is most definitely wrong with your set up or carb. I have never seen one get hot to the point of bubbling the cowl. 6500 on a 22x8 is way off power wise also. We normally see 7000-7100 on a 22x10 mejzlik. It would be best if you could send the engine to us.

Keith
BME

Keep us posted, OK

I had someone look at my set up and they immediately asked about my muffler type. As far as I know the guy who sold it to me said it was a Slimline pitts style muffler. The guy at the field said that the muffler I have was not designed for use with the BME 50. That may be true since the previous owner said he needed to machine a special adapter/spacer to mount the muffler. The muffler looked real nice and all to me at the time so I didn't think twice about it. I did get to see a J&A muffler that someone else had and I notice the canister size was a lot bigger than mine and also the exit pipes on the J&A were much larger. So I am going to try and tach the motor without the muffler to eliminate that possibility.

I went flying with it yesterday by the way and had other problems like the muffler kept coming loose and I lost my canopy in the woods somewhere. I never tached it but the flying performance was lackluster. With the cowling off I did not notice a heat problem but it was running a little rich. The richening in the air problem may be due to my open F1 former which allows my entire fuse to be pressurized. I didn't notice the richening problem when my cowling was on.

If you're using a muffler that's too small it will surely fry your engine and lead to poor performance. No question. That friend of yours who sold you the engine probably thought the performance was bad too so he sold you the engine for that reason. Put a JA Muffler on that engine and then watch out. The perormance will thrill you.

What engine did your friend buy when he sold you that one?

Actually it sounds like this engine has been beat up pretty good by your friend before he sold it to you. If he used that muffler then there is no telling what else he did wrong with it. The plugged idle needle leads me to believe that he didn't use a fuel filter either. The BME 50 is a great engine. I hope you get all the bugs worked out and come to see what a fantastic engine it really is.

I examined the engine before I ran it and it looked brand new to me. It looked like the factory never ran it either so I seriously doubt that the former owner even knew about any of these problems. Not to mention I do trust him. I really don't think the engine is damaged since I never let it run lean like that for more than 20 seconds. Anyway without the muffler I tached the 22x8 Mejzlik at a top rpm of 7100 rpm without adjusting the needles at all. Boy would I like to see that with the muffler on.

I almost forgot to mention the guy who looked at my setup at the field said I may have problems due to the use of med sized fuel tubing instead of the large stuff. Do you think that would make any difference?

I don't think the fuel tubing is a problem if you got the engine to finally run with the muffler off. Sounds like you're on the path to a good running engine. Get that JA muffler on it and your problems should be over. Back in the day we used to throttle our boat racing engines with an exhaust valve. Close off the exhaust to go slow and open it up to go fast. That little muffler you have is doing the same thing to your engine.

Thanks, but where do I get the J&A muffler from?

Chief Aircraft sells them and so does BME. JA also have a web site. They are expensive though, about $99.00. Your engine will love you for it though. These Babies love to breath.

J&A Muffler

http://www.j-aengineering.com/

Crap my post got erased. I have to type it in again. I did some research on the muffler issue and I found out that I have a modified Bisson muffler. Not sure exactly which one but the measurements are very close to the ZDZ50 muffler they make. It's modified because the outside corner has been cut off and a flat piece welded on. The thing I don't understand is my current measurements are larger than the J&A measurments listed on their web page for the 2.7 bme. I didn't see anything for the 3.0 on their web page. Am I missing something here?

Just got off the phone with J&A and they said there canister for the bme 50 is 1.5 in. dia. (mines 2 in.). They said the big difference is in the output tubes wich are 3/4 in. dia. (mine are 5/8 in.). So If I get new output tubes welded on that should be real close to the J & A. What do you think?

I'd say it's worth a try if you don't have to pay to much to get the tubes welded on. It can't cost anywhere near the $99 J&A gets for their muffler. Why not! You can always get the J&A later if it doesn't work. Also make sure your exhaust port on the muffler matches the engine. If it's smaller you will still have some restriction of the gas flow. Good luck.

It looks like your muffler is for the 44?

Joe

The muffler for the BME 44 and 50 are the same as far as I know. I've had both engines.

Bigger fuel tubing would be helpful to I would imagine. My Moki 180 runs on medium size fuel tubing up to large, I think the size was 5/32 ID tubing for the 50cc range? Am I correct or do you all run medium size tubing?

Gas engines do not suck the fuel like a glow. Hence, no comparison with your Moki.

True! I have a BME 50 and a 16 oz tank gets me 14 minutes of flying.

It looks like I'm going to order the J&A. Is everyone satisfied with the noise level with this muffler?

If the muffler doesn't help the situation I will just keep running it till it breaks in. As long as it won't overheat I should be ok. I'll re-evaluate after five gallons.

I think the J&A Muffler sounds just fine. With a 22X8 prop that I use on mine it's a very nice setup. I'm using a 22X8 NX prop by Airwild for break in and will switch to the 22X10 later on.