I have a 2 year old Stihl BG86/C Hand held blower that idles fine but won't rev up when I pull the trigger to do so. I changed the fuel, took the carb off and cleaned it with air gun, Checked the spark, and the spark plug. It used to blow leaves across the yard, now I'm lucky to move them 3 feet. I could replace all of the above, but am looking for a smoking gun before I do that. Any clues as to the most likely culprit?

 

You say it "won't rev up". Do you see the linkage at the carburetor or the throttle butterfly move? Basically, do you think it's a throttle linkage problem or something clogged in the carburetor?

 

Blowing the carb. with air is not going to do anything to clean it.
Been using ethenal fuel?
Replaced the fuel filter in the tank?
Does it stall out when you try to give it some gas, of just not do anything to change the RPM's?

 

Check the throttle linkage, it may have slipped. When you pull the trigger to rev up does it bog, if so open the l circuit by 1/4 turn counter clockwise. Have a good one. Geo

 

I'd check to be sure the spark arrestor in the muffler is not plugged up with carbon. If not, open up the high speed mixture screw just a tad.

 

Ok, All the linkage is hooked up and moving the throttle plate etc. No I blew out the fuel filter but did not replace it. When I pull the trigger to rev up, it does bog big time. Turning the jet (hi speed) does not help, just makes it worse than the low speed it altready maintains. so does turning the low speed jet adjustment. I don't use ethanol fuel other than what is normally at the Speedway regular gas now. this blower went from hauling the mail to next to nothing almost immediately. I did not want to soak it in regular carb cleaner without a recommendation.

 

I did not think about the spark arrestor. I will check.

 

If it's not a stopped up muffler then change the carb, instead of trying to rebuild it.
I've owned nothing but Stihi brand gas powered lawn tools for many years, (pole saw, blower, 2, chain saws, 2, trimmers, gas powered drill) The only issue I've ever had with them is a dirty carberuator.
Tried buying the $14.00 rebuild kit and cleaning it myself. With all those tiny ports, and parts it was a real pain, ad still did not run quite right.
Next time I bought the whole carb., I had it changed in about 10 min. and it started right up and has been running perfect for over a year.
I only mix one gal. at a time, only use fresh nonethenal fuel, at the end of the year and if I know a tool will not be used for a long time I dump out the tank and let it run until all the fuel runs out.
I also almost never push the primmer bulb if the tools been used within a week.
All my trimmers, and pole saw will most often start first pull.

 

Thank you for the help and replies. It is up and running normally now. (Per the Cheesman, I couldn't get the muffler off without a new set of deep well torx bits, so I ran some wire and a small stiff Brush (sort of like a colonoscopy) and nocked some carbon out. (there must be a screen inside the muffler) Just put the covers back on and fired it up. Had to do some fine tuning with the jets that I messed up trying to force things.

Have a great day!

 

Glad you got it going!
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My BG56 had a bad ignition module. I bought my BG56 and I think I put too much strain on the module cleaning a large tennis court nonstop. I had started off with basic things, cleaning the carburetor (or replacing it) cleaning or removing the spark arrestor on the muffler, cleaning and testing the spark plug/air filter. The fuel pipes going into the fuel tank have to form a tight seal (replace grommet around connecting piece that plugs into fuel tank) or the fuel primer won't work 100%. Pressing the fuel primer when its running causes it to stall (insufficient spark) or run better (insufficient fuel).

A good way of fastening the ignition module is to place several layers of paper/card between the module and magnetized section (or non magnetic opposite section) of the flywheel while you tighten the screws. Minimum gap produces optimum spark. If you remove the flywheel don't let metal objects stick to it as it loses its magnetism.

 

I have been using a new business card to gap the ignition modules for years, it has worked on all the modules I have installed or adjusted. Have a good one. Geo