Outdoor Power Equipment and Small Engines - Stihl BG75 Blower

Hello, i am new to this site. I have a Stihl BG75 Air Blower and have a slight problem. It turns on and runs fine, but as soon as i press on the throttle the blower decides to turn off completely. It's like a dying sound. I have taken the entire unit and engine completely apart, cleaned it and rebuilt it, but still the same problem. I also played with the air/fuel screw on the carb both at idle and as well as when i grabbed the throttle. Nothing worked. I cleaned the spark plug well, but maybe i need a new spark plug to fix the problem??? I don't know. If anyone could respond soon that would be a huge help. Thanks! -Jon

Is it a 2 cycle engine?

If so, the mufflers tend to get gummy with oil and block the exhaust from flowing freely enough to run above idle. Take the muffler off and burn out or soak out the oil and give it a try.

Yes, the unit is a 2-Cycle. That sounds like a good idea, but if it does not work still, do you have any other suggestions i could go with? I am definetly going to buy a new spark plug because it has never been replaced, just cleaned. Thanks! -Jon

Make sure there is no obstruction in the fuel lines or in the tank. Some small engines have an inline fuel filter. Most have a screen in the fuel tank. Be sure you have good fuel flow. Be sure the fuel line has no obstructions or cracks in it also. If it has a primer bulb, be sure it is not cracked and sucking in air.

I do not know the correct settings for the idle air or high speed settings. Maybe another here will take over from here.

Alright, thanks for the help. -Jon

Let us know how things go. There are folks here that know much more about small engines than I do.

I think they went to bed already tonight though.

Alright, I'll do that. I'm going to give all that stuff you recommended a shot tomorrow, after i replace the spark plug to start things off to see if that's the problem. Then i'll post another thread. Thanks! -Jon

The muffler is a good place to check, but it doesn't usually cause the engine to shut down completely. It's still worth a look.

I think the carb is not delivering fuel correctly. Have you cleaned the carb? The high speed mixture screw is the one (of two side by side screws) that is closest to the air filter. Try backing it out 1/4 turn or so.

Hi Cheese, Yes i have played with that screw when it was at idle and also while i was grabbing the throttle. I will post another thread once i replace the spark plug and clean out the muffler today around noon time. Thank you! -Jon

Well, i took the muffler off again and burned it out to clean it, it looks much better,and i replaced the spark plug, and still, it does the same thing. I also played with the idle screw again, which is the only screw on my carb besides a random screw that prevent the throttle cable from dropping too much, which i already played with that too. I have no idea what is doing this, but it is very annoying!! Would you suggest doing anything else before i bring it to a store to get it checked out? Thanks! -Jon

Okay, now i fixed it. I took the carburator out AGAIN, and this time, i completely re-built it. I took as much as i could out of it including springs and everything, cleaned it out real good, and re-assembled it. It works now! I guess there were some particles stuck in the actual chambers of the carb. The only question I have is when it actually blows at the highest power, are the rpm's supposed to drop a little bit and then rev up to full power when you press on the throttle? It works everytime, it's just that my rpm's drop a little until it reaches full power. I guess it's ok for that to happen seeing that it works all the time? Thanks! -Jon

Probably a little tweaking of the high speed screw would stop it from doing that. You said you fiddled with that screw, but then said it only has an idle screw. If it has no high speed screw, i'd be satisfied with it if it works well.