Ben, guess the only way for you to find out is to give it a try like you said. 2 turns may be ok?? seems just a little much for me.. but the RPM's we achieve on our engines is pretty high compared to the industrial use they get.. Let us know how it works out for.. Regards BobH

bdphil, sure hope you figure it out and relay your info. I have a BME50 going in a Pitts real soon. It's my first adventure with gas and if anyone will experience strange problems, it'll be me, lol. good luck

gare,

I'll definitly let you guys know how I make out as sson as I get a chance to try it out again. The weather's been terrible here lately. I'm sure the problem I have has a simple solution, I just don't have alot of experience with these engines.

Barring any unusual problems, you'll love this engine. Lots of power!

Good luck,

Ben

I'm having a little trouble adjusting my BME 50 and I think it was an intermittant, then complete sensor failure. Im waiting for a replacement part now. Just a thought if you have more trouble.

Peter

I might be totally off base, but I had very similar problems with my 100. I thought for sure I was just too lean, but the plugs were black. Turns out it was overheating due to the design of my cowl - all the air was running under the engine, and not up and over the cylinders until I put in ducting. These things will store heat for a long time inside a cowl, have you tried running it without a cowl?

Well after several weeks of crappy weather I had some time to fiddle with this darn engine some more. After running OK on the bench I put it back into the plane and headed for the field. First two flights went fine, engine ran real good. Fired it up the third time and it sounded bad (surging a bit). Tried to advance the throttle and it refused to accelerate. So I figured I'd open the low needle a little and it seemed OK on the ground, but after a few minutes in the air it was threatening to quit when I tried coming off idle. I figured I'd better quit flying it for the day.

Next I decided to mix up a gallon of petroleum based 2-stroke oil (pro-honda GN2). Headed back to the field. Started the engine at high idle and let it warm up good. Down to low idle, engine surging erratically and hesitating off idle. I guess the synth. oil wasn't the problem.

So today I went to the local small engine guru and talked for about an hour with him. He suggested that a leaky seal or worn gasket could could cause erratic fuel delivery. He said that he has located this problem before by spraying starting fluid around the seals with the engine running and if a seal is leaking some of the starting fluid will be drawn into the engine and you'll be able to hear the effects. So I tried that. No noticable difference. He also suggested that the spacer block between the carb. and cylinder could be warped and that you can compensate (for diagnosis mind you) by doubling up the gaskets on either side. So I punched out a fresh set and tried that with no success.

Before all this I tried the carb. mod. on the IMAA website and that didn't seem to help either.

I also thought that since the engine worked the other day for 2 flights, that the problem could be the ignition battery. I started that day with a freshly charged pack and thought that as the voltage went down maybe it was causing problems. So I charged the ign. battery and it didn't make any difference.

So what does one do at this point? I called and ordered a DA50 and will return this one to BME for a look. Hey, at least now I'll have an extra engine lying around (so what if it doesn't run).

Thanks to everyone for the suggestions and I'll let you know what I hear from BME.

Ben

bdphil,
Did you see the result tailheavy had with his BME. It was a plug in the low speed needle under that little cap. I forget what you call it. Here is the link to the post.

http://rcuniverse.com/showthread.php...78#post1099878

The ignition may be your problem. C&H has had to replace some of the syncro spark units due to them being heat sensative. I think this would be worth looking at. Also if your carb is working right and its the wt-201 the needle should be close to 1-1/4 turns out on both the high and low needle.



Keith
BME

fancman,

I've been following that thread, thanks. I don't think that the carb has any passages plugged up because it typically runs fine for 1 or 2 flights then acts funny.

Kieth,

First off, thanks for replying to this thread. I've been meaning to call you and see what you thought about this engine, but I was sure it was something simple that I could straighten out.

Would the ignition heat up from it's own operation because I had it mounted in a location that wouldn't get too much heat from the engine? The cowl was also opened up a good deal to keep the engine cool. Maybe I'll send the ignition in for a look (I was planning on that anyway).

Ben

My money's on the ignition. Second possibility is the ignition wiring/switch being intermittent. I struggled with another setup that was done by someone else and the guy did a lousy job on the ignition harness I had to replace all the wiring and redo all solder joints to the switch. After that it worked great. You could have vibration damage or just an intermittent component in the ignition. If you get one of those ignition checkers it may test good but it's not under the same vibration when it's in the plane. Just use another syncro spark and see if that eliminates the problem.

But before you do that if you really want to have peace of mind about your carb you could get another one for about $35 from Kieth at BME or buy one at you local lawn mower shop. If I were you I would have to have the carb examined thouroghly and that means looking under the Welch plugs. They sell carb kits at the local lawnmower shop. Or you can have one of the experts there do it for you. Either way once your carb has a clean bill of health the only thing left is the ignition components short of a rare crankcase problem.

Tailheavy,

I'm gonna have the ignition looked at (when I get back from vacation). I thought of the power connections for the ignition and replaced the switch and battery with no change. It's either the carb. or ignition module I think. I'll let you know what I come up with in a few weeks.

Ben

From what I understand about the faulty ignition is that the syncro chip inside became heat sensative. Most will tolerate 180 degrees but some defective ones including our own would run fine if the plane was in the shade but if allowed to sit in the sun it would not fire. This was on a 95 degree day. Some will run a while and then reach shutdown temperature. Bill at C&H is working very hard to change out the defective timing chips.


Keith
BME