Diaphragm carburetor

[Wheels]

This isn't really Blaster related but I thought you gear heads might find this interesting:

I picked up a Stihl saw last year that was missing some parts. I spent $100 putting it back together and proceeded to saw down enough trees to piss off a camp full of hippies. It recently started bogging at full throttle and became hard to start, I pulled the carb and found this :-/
USA Zama : Service Tips
It is the first time I've seen one of these and I think they're pretty awesome.

I cleaned all the passages and the parts of the diaphragm that were clogged with saw dust. I'm pretty sure it's ready to rip again, I just have to wait till tomorrow to test it so I don't piss of the neighbors.

 

[jus_me]

I have one of those on my roto tillers. There should be a little screen in there depending on the model#,,theres tons of them zama models,,check to make sure it's clean, and there no cracks or holes in the diaphram.

 

[Wheels]

I think the issue was that there was so much saw dust caked on the side of the diaphragm that is exposed to the atmosphere that it couldn't expand to pull in fuel. You'll know if it doesn't work because I'll be right back here tomorrow, lol. Up until today I always wondered how this saw ran so well no matter what angle I put it at, now I can't believe it took me so long to come across this.

 

[jus_me]

Lol yeah those little carbs are cool and run at any angle. I have a72 kitty cat sled for my son and he kept putting it on its side so i went with a diaghragm carb from a small toro snow blower its works tremendously well. Now i don't have to kill my arm starting it all the time it runs on its side now lol.. Stihls and Huskys are the best saws imo...

 

[Wheels]

I love this saw, it's definitely a screamer. Unfortunately I think I jinxed myself, it still doesn't run right. It has 140 psi compression and good spark, I think the problem may be elsehwere in the fuel system, I'm going to look in to that and maybe figure out how to leakdown test this thing.

 

[Wheels]

Saw's fixed and runs like new again. I really wish jetting a Blaster was this easy, each jetting circuit is metered like a fuel screw on a four stroke.