Recent content by EFSM

Those air filters should have won a gold metal for stupidity. You’d have to specifically design it to be overly complicated to get it so perfectly bad—what is so bad about a choke shaft anyway?

Who is “Run”? My schoolteacher OCD showing up—you can see on one of the pictures that someone wrote “run’s” instead of “runs” on the air filter cover. I was teaching possessive nouns/adjectives last week so this stood out to me.

The Echo 4910/501 platform is much newer and can be a really mean saw, but it is rubber antivibe so not as comfortable as a spring-isolated saw (550, 261) if you’re running it for hours at a time. Both the 260 and 501 are limited by carb options if you’re after exotic power.

Is it fog mixed with something acidic or corrosive?

Walbro carburetors are overall much better quality than Zama. This is mainly due to the vast difference in the rubber quality, which means that Walbro has almost zero issues with check valves and accelerator plunger o-rings.

Swap a no name Chinese carburetor for a named Chinese carburetor. Sounds good to me.

The choke may not be shutting the whole way. Take the air filter elbow off the carb and put the mounting nuts back on to hold the carburetor in place and then test the function.

my bad I badly misread your post

I wasn’t aware this was a customer’s saw.

I’ve already used a feeler gauge shim and extra-high strength thread locker in a pinch. It’s not like you have to do something special to beat the strength of aluminum.

concrete saws sometimes have o-ring or flat face seals on the throttle shaft

If it's not running poorly, then you don't have anything to worry about.

You don’t. It’s only a factor at idle, which is when there is significant vacuum there.

It is probably getting around the throttle shaft.

How are you diagnosing the leak? Leak down test or spraying ether/carb cleaner?