395XP carb problem

[super3]

Got a call an hr ago from one of the local loggers I port saws for with a problem with the last saw I did up in Aug of last yr.
After around half a tank of fuel the idle will be racing and he has to back out the LA to normal. Go to the next tree and by the time he is finished with the cut it's back racing again. Same on the next,etc,etc,etc. Wanted to know if he could drop it off on his way home?

He stopped by and I asked if it done the same bucking or just when he was falling. Only falling. Told me his Uncle who I also build saws for has one doing the same along with his boss's saw (this one is stock) all 3 only when falling. All saws are 395's and new last yr.

Quick check of the LA and it seemed a bit too easy to turn. I just happened to have a saw I did for him in July 2014 here for a full rebuild. I grabbed that carb and the LA had a lot more resistance. Took them both out and miked the threads and the newer one is .002 smaller. Wound the old one in the newer carb and the resistance feels like it should.

I'll be ordering a few new LA screws in the morning to get some measurements off them.

 

[Chainsaw Jim]

A husky screw tightening itself?!!!!
I'm putting on my tinfoil hat right now.

 

[super3]

It was a bit hard to believe myself.

 

[huskyboy]

I had to fix a brand new walbro by putting a spring under the idle screw. Same thing on a zama too before.

 

[Chainsaw Jim]

For those with no spring handy, red loctite works good too. You wait for it to start setting up before you turn the screw back and forth a couple times to leave it at the desired resistance.

 

[paragonbuilder]

A husky screw tightening itself?!!!!
I'm putting on my tinfoil hat right now.

It was a bit hard to believe myself.

If it’s loose in the threads it makes sense, throttle is off the screw, gravity and vibes do the rest.
It’s not tightening, just turning.


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[Chainsaw Jim]

If it’s loose in the threads it makes sense, throttle is off the screw, gravity and vibes do the rest.
It’s not tightening, just turning.


Sent from my iPhone using Tapatalk

That was just like watching outrageous acts of science where they explain why a football fell off the tee during a windy day.