Come on Scott! The carb had that impulse outer port blocked from day 1 out of the factory. Yes I could drill it out, but clearly Zama intended it that way. Everything I'm doing currently is merely attempting to bring it vaguely to spec. I consider cleaning all the passages underneath the Welch plug the next thing to do in pursuit of that aim.
I know! I couldn't agree with you anymore!
Well the vast majority of 200T were fitted with carbs with the orthodox un-blanked port, so that will be why.
I know. It's weird. Will try to drill the port through prior to the Welch plug.
Care to elaborate?
No problem. Always happy to share information.
That would be my pleasure.
I just got a 35 year old 020 AVS running the carb may have been the original Walbro made Japan I cleaned it out with carb spray and it runs fine! Aint no way one of those Zamas made in China on the 200T would hold up that long.Last week three Stihl top handle saws arrived for a check-up -- 192TC, 200T, and a 201T. Guess which one ran the poorest? The 200T, of course. The other two saws start and run normally.
The 200T starts poorly, cannot accelerate to WOT very well, and tries to conk out instead. No carb settings, Lo or Hi, change the situation. Sound familiar?
Well what do you say is the cause?Last week three Stihl top handle saws arrived for a check-up -- 192TC, 200T, and a 201T. Guess which one ran the poorest? The 200T, of course. The other two saws start and run normally.
The 200T starts poorly, cannot accelerate to WOT very well, and tries to conk out instead. No carb settings, Lo or Hi, change the situation. Sound familiar?
Not sure, of course. I'll try my typical complete clean up first. I've checked the pickup and fuel line and they're OK. I usually do that before I pull the carb. This smells a little like a clogged strainer. I'm hoping that's all it is. There may be 150 to 200 hours on this saw, used by a commercial tree trimmer.
Impulse line off or loose?
. The inner hole I drilled through to, you can see here:
Interesting to see what you have after a bit of testing under working conditions and getting the tune just right .Well I couldn't be bothered to wait for the welch plugs to arrive. So I took the plunge and drilled the impulse port through. If anyone says "drilling a little lump of alloy held at an oblique angle in 2 planes whilst turning the handle on a drill press with the other hand" is easy - I'll say "suck my d**k". Oh and of course the bit was only 1mm diameter, with the rigidity of a drinking straw.
I took some piccies but the exterior port is out of focus and the carb is in a saw now, and plus I'm about to eat my tea
View attachment 105844
and that dotted line is the passage that the drill hole took from the outer port.
After I quickly blowing clean and reassembling.....it started, and ran, and idled just fine!! Really pleased! I now have a spare genuine ZAMA 200T carb. I'll give it a tank or 2 of gas this weekend, but it looks that it really was either a production fault, or as @Simondo speculated the blanked impulse port could only function properly with a working accelerator pump system.
Definitely. Well I reckon I've got a spare carb out of the deal. Which for a 200t is always good. Will post back this w/end with an update.
I gotta love the dark pink carpet you've got there in yer workshop buddy! And do I spy a notes pad with a pen at the top right of the pic?? Nice and organised.....
