Chainsaw Repair

Built a 345-346 (42cc version) hybrid this week. Learned a couple of things and have a question. Learned:

1) Walbro carb from that 345 doesn't work well, especially idle & just off idle with the 42cc 346... A Zama fixed the issue
  1a) Looks like the Zama has a "hole" in the throttle plate in addition to the "notch" on the edge...wonder if drilling a hole in the Walbro's  throttle plate makes it useful?
2) Had to take around .050 off the cylinder screws.
3) Had to die grind a bit off the clutch side of the transfer port external casting to have that cylinder not interfere with the plastic case....
4) Learned it's a great running combination with no base gasket, a muffler mod and a bit more intake duration!!

Question:
The sawwas an older variant with the "course" thread mounting hardware for the cylinder and bearing cap. I put it together with 1194 AND generous amounts of 1194 on the threads of the mounting screws both top and bottom (cylinder to bearing cap & case to bearing cap) Is that going to stay together??? Or should I break that saw build down and either heli-coil to fine threads or put an aftermarket (Huztl) fine thread bearing cap in there??? Been bothering me...

You talking OE 42mm bore 45cc 346 top end here?

My old 45cc OE has smoked a few ported 350s'. You either have a very strong 350, and/or something is not right with this one.

your results o'drilling or notching the throttle butterfly may vary from mine....anyhow, what i found..
-some benefit can be had, but the idle rpm has to be kept in check.
-where the hole is located plays quite a role.

have to believe that most of these carbys are pretty linear already.  messing with holes can turn the carb tuning upside down.  will take hours just to balance the low/high jets, from my experience.  imo, most of this drilling is unnecessary, for the small gain to be had.  not saying that the gain is not there, just not worth the time for most.

when the hole produces a noticeable gain, idle goes away.  don't know what your goals are, but mine were to make it more adjustable.

the air bleed, first hole has a large influence on the transition to the HS jet.  imo, is just as important.  when LS trans jets are drilled bigger....., with the bleed drilled at the same time, hope you have some hours to kill for tuning.

if the needles are see sawed....i cannot understand how it can it be better???

good luck in whatever you decide to do.

-joe

When I ran stock OE 45cc against NE 50cc the OE had noticeable less torque.   

Now ported 45cc I had 2 by Dan Henry dozerdan. His 45cc port work out cut almost all the 50cc ported saws I ran against. I had a 50cc ported Dan Henry saw on hand and there was only 1 other 50cc 346 that ran with it at GTG's.   This was with 3/8 chain. The 45cc stock to me is a .325 chain saw.  Ported 45cc by dozerdan was a 3/8 saw all day.