Hi Guys, It has been awhile as I got distracted with a few other things, finally found the time to pull this apart and discovered that I can be lucky sometimes but generally compensate for that with stupidity. It was missing a mounting bolt which must have rattled out of the bottom at some point. This may of may not have contributed to the problem which was the engine had been rubbing against the shell and worn through the insulation on the kill switch line. That coupled with an accumulation of oil and sawdust allowed it to short out sometimes and not others
Unfortunately I could not help myself and had a little fiddle with the carburettor. I put the motor in the vice and tried to start it with a drill, with no success so I disassembled the top part of the carb and found there was no fuel getting through the main valve. I used up the rest of my can of carbie cleaner trying to clear it then rather foolishly I bent the float valve arm a little bit, which did not help. I pushed a tip cleaner down the float valve seat, probably foolish as well as not helping, eventually a tip cleaner through the feeder hole to the float valve moved some thing. Reassembled it put it in the vise and it started first time and ran but very loud. I fiddled with the mixtures a little bit and although the high one did not seem to make much difference I imagined it was about right. (I was reluctant to try this with any revs as it was pretty noisy)
It only took a day and a bit to put it back together (they must have had some special tools and a jig of some sort at the factory) The missing bolt although 1/4 inch was not UNC or UNF and was not metric either. I tapped one hole (where I can put a nut on the other side if necessary) with a 5M metric tap.
Started it up, and it was necessary to keep working the choke back and forth until it got warmed up and seemed to be running fine, but as soon as you touch the accelerator it dies. I let it warm up and fiddled with the mixture a little bit but keep getting the same result.
I don't know if any of this points to anything specific, the diaphragm was in fairly ordinary condition but I would think it would either work or not work with no in-between.
The carbie is a ZAMA M7 3YB I cannot get anything for it locally but I can get a kit from China (sometime in the new year). The kit does not have the mixture screws or the float valve arm, just the float valve and spring.
The $5.00 investment for the kit is probably worth it but I am not sure about the day to take it apart and put it back together again. (I am assuming It will only take half the time as originally)
Any suggestions are welcome
If I can get a large enough hammer it will run for awhile just trying to get away from me
