I have a BME 44 which until recently ran fine. I had to replace the hall sensor and while I was at it I installed a new bosch plug cap from CH. I went to start it today, and found that while it idles fine, once the Tx stick moves up the engine speed only increases a little bit and then stays pretty static. Every once and a while it will surge a little bit like it's trying to go to full throttle, but it doesn't. The throttle linkage is moving fine, and so is the butterfly, so I'm assuming its the gas system somehow, and probably has something to do with the high speed needle. Any ideas out there? I'm not very experienced with gas engine problems, because up till now the ones I've had worked great. Any assistance would be appreciated.
Thanks
sam

The first thing I would try is adjusting the needles, don't be affraid to touch them.

#Set High needle for peak rpm and back off a couple of hundred rpm. (in your case close the high needle and start at 2 turns open)
#set the low for good idle and transition.
#3Re-set the High for peak and back off a couple of hundred rpm. Always re-set the high after setting the low. (low affects high)

After that I would check the carb to see if any crap is in it. Then go thru the fuel system, lines, clunk, etc.

And make sure your battery is charge and in good condition.

It ran fine before you had to replace the hall sensor and then put a new plug cap on it--right?

One of those things is what fouled you up.

Did you tweak the timing or mess with the timing when you put the new hall sensor in?

Did you check the gap on the hall sensor and the crank magnet?

Did you charge your ignition battery?

Old fuel--maybe? If you've left fuel in the tank for a long time--the OIL can come out of suspension. Then your sucking straight gas up the fuel lines and causeing it to run lean---all the oil will settle into the bottom of the fuel tank if it sits for an extended period of time.

Thats why I always drain my tank after the day. And your 1 or 2 gallon can will get plenty shaken up on the drive to the field. If your flying right outside your back door--and the fuel can sits around---ALWAYS give it a really good shake to help make sure the oil is all mixed up.

Someone is going to come on here and tell me that oil stays mixed--once you add it to the gas. And I'm here to tell ya--thats BS. Shake it up.

Thats how lots of guys with snowmobiles ruin their engines or gum up the carbs. They leave the fuel sitting in the gas tank all summer. Then come next winter--they just fire it up--without ever thinking to put a stick in there and swish the fuel around for 10 minutes. The oil in the fuel has all settled to the bottom of the tank. When you pull the rope and fire it up---your either sucking oil off the bottom---and then it gumms up the carb. Or--your pickup isn't right on the bottom of the tank and your sucking straight gas from up above the oil thats all settled to the bottom of the tank during the summer months. Your snowmobile runs like a raped ape for about 7 minutes--then--it takes a cr@p.

Shake the tank and "re-mix" the oil and gas. Or drain it and then add fresh gas---especially if it's been sitting for a long time--like over the winter months.

I doubt the problem is in your carb. It's either the timing--because you replaced a part and may have inadvertently goofed up the timing. Or you got a bad hall sensor. Or maybe your connection is bad between the hall sensor and the ignition box. Or it's your fuel/oil mix.

Sorry to rattle on so long. Hope this helps.

Rcpilot-If his BME is like mine (different size) you can not mess up the timing by replacing the Hall sensor. I have found they either work or don't. You did give a lot of good advice that I hadn't thought of.

Then again I don't own a 44 so I could be full of it when talking about the timing.

I had a BME 50 that did the exact same thing. Replaced the ignition box, and all was fine again.

Thanks for all the great advice. Here's a bit more information: The reason I had to replace the hall sensor is becuase when I was troubleshooting why it would not start at all the other day I noticed one of the wires from the sensor was cut, most likely by the "sleeve" I put over the wires to protect them. Somehow while messing around with the plug, etc, I must have tried the ignition ungrounded, and the hall sensor went out. I ordered a new one from CH, and it came installed on a small peice of metal which just bolts on in place of the old one, so I am assuming that I did not change the timing. I also soldered on a new spark plug wire to the coil. The old wire had a carbon core and had just been pressed onto the coil pigtail. CH said to solder the new wire onto the coil pigtail, so I did , and it looks okay. I tested the ignition with the plug out and it fires every time I turn the prop shaft. I also regapped the plug, and maybe screwed it up? I'll try swapping out the plug and see if that does anything. The battery pack is fairly new and was right off the charger, so it should be fine. It seemed to take a flip or two more than usual to start, but did start up and idle well. How do I clean the screen in the carb, or maybe a better question would be where do I look for dirt in the carb?
Thanks again for all your help.
Sam

Today I put in a new plug, and took the covers off the carb and cleaned the screen. I also took out the needles and blew cleaner through the openings, and in both cases it came out the carb interior. I did notice that on one side of the carb the rubber sheet (diaphram maybe) was beginning to delaminate, but only on the part outside the cover which hooks over the little nubs. I tried running the engine and adjusting the needles, but same thing as before. It sounds like it wants to run, but can't. The grass under the exhaust seems pretty wet, like it's getting enough fuel. Even though I put the hall sensor back in the same spot, is it possible that the sensor itself was not in the exact same place on the metal mount as the first one? The engine did see like it was a little hot, but seeing as how it only got to a few thousand RPM I don't really know how it could be. It does sound like its four stroking, just not able to break into two cylce.
Thanks in advance for any more advice.
Sam

Okay, I broke down and tried Ralph's method of checking the ignition timing, and it looks like it may have been a bit retarded from the 28 degrees it was supposed to be at. I'm going to reset it tonight to 28 degrees and see how it runs tomorrow. Just to double check, Ralph, if you're reading this, if I've found top dead center, gone CW (looking at the front of the engine) 28 degrees ( I think it worked out to be .366, and then loosen the timing ring and move it so it just fires, that should set the timing to 28 degrees BTDC, right?
Thanks
sam

Engine runs the same, with timing adjusted to 28 degrees. Called CH and they said I may have broken the secondary coil wire when I soldered the center wire from the new ignition wire. Sent it back to CH today, and we'll see.
Sam