*Chainsaw RPM Problem*

Unresponsive Trigger

By Jaden

08 August 2004

 

The chainsaw my dad has started acting funky. It would start up, but when he pulled the trigger the RPMís didnít increase. I decided to look at it. First thing I did was start it so that I knew what it wasnít doing. Pulled the trigger, nothing. Ok, surgery time. I pulled the air filter off to get to the carburetor and found sawdust on the INSIDE of the filter. Hmm. Thatís not good.

Air filter on

I checked the throttle linkages to the carburetor and they were fine. I immediately guessed that a woodchip had been sucked into the carb.

Carb on

Pic taken after I cleaned it

I unscrewed the carburetor and removed it. It was quite dirty. I poured some gasoline into an old soup can and gave the carb a bath.

 

Gas bath Carburetor

Behind the carb is a one-way flapper valve. I found a good-sized hunk of sawdust on it. It was holding it slightly open.

The gray circle is the flapper

I removed the flapper assembly and cleaned it. Then I put everything back together and started the saw. The throttle worked.

How did the chip get in there?

The saw belonged to my grampa before he died. He was the type of guy who would put pennies behind fuses because they kept blowing. We figure what happened is, he was using the saw and the filter plugged up so he took it off and continued using the saw. A piece of sawdust got sucked in and went through the carburetor and got stuck on the flapper valve.

If you chainsaw ever has this problem, check for junk where itís not supposed to be.

Jaden


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