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Ok sounds good. So when the motor reciprocates and draws air through the carb throat and hits the venturi causes a pressure drop and pulls fuel in through the main nozzle? What happens if the check valve is bad ? Reverse flow? Is there a way to check the check valve in the main nozzle?
if a main nozzle check valve sticks open it will affect the idle but can run fine at wot...since the check valve opens at wot anyways. but at idle it can suck air back into the metering chamber which will basically lean the saw out until it dies. ive never seen a main nozzle check valve stick closed...not saying it cant happen...anything can happen, im only saying ive never personally seen it. i seen stuck open check valves the most on 026/260 carbs, wt22's and wt194's. of course this is only my experience. they are fairly easy to test with a pressure/vac gauge...at one time we had a modified carb cover with a nipple jb welded to it to hook the gauge up...ill see if I can find it.
 
This got dropped and the nipple came off but here's the two pieces. Just drill a hole in a spare cover to fit the nipple...this one would fit a wt walbro. Then what it looks like together. Just needs a little jb weld. On a wt22 or 194 you would close the low side needle all the way. Put this cover on with a gasket and you could pressure check the main nozzle check valve. Of course there's other ways to check them...this is just an easy/convenient way to do it.
image.jpg
image.jpg
 
This got dropped and the nipple came off but here's the two pieces. Just drill a hole in a spare cover to fit the nipple...this one would fit a wt walbro. Then what it looks like together. Just needs a little jb weld. On a wt22 or 194 you would close the low side needle all the way. Put this cover on with a gasket and you could pressure check the main nozzle check valve. Of course there's other ways to check them...this is just an easy/convenient way to do it.
View attachment 467050
View attachment 467051


That looks like paraphernalia of some sort.
 
Lil eye candy! 440 I put a new piston and cylinder on this morning for a customer. 180psi. Muffler mod and timing advance. 102/120/72 is where she landed so I didnt do any port work. Tuned her to 14000 and she is a runnin son of a gun! Odd bar setup being a 22" Stihl ES .063View attachment 467069
Those are some good numbers, it could probly use a little more intake. But I bet it would run a damn good while on a tank!
 
Those are some good numbers, it could probly use a little more intake. But I bet it would run a damn good while on a tank!
Ya but the customer wasnt paying for a port job but just a cylinder/piston change! Lol! I figured I would just check the timing while I was there out of curiosity. Probably woulda took the transfers to 118 and intake to 77 or 78 if they woulda ask for porting
 
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