An interesting thing that that I've learned from our engineers (Rob and Col) is that diaphragm holes can be quite fine and quite concealed. The need is to hold the diaphragm up to a good light eg sunshine while VERY GENTLY stretching it out section by section. The offset is that with older diaphragms the act of stretching them may induce some cracks. Remember to locate the diaphragm lug into the detente position of the carby body when reinstalling! Laurie
Sent from Yahoo7 Mail on Android On Sun., 17 Nov. 2019 at 7:12 pm, Rob Thompson<[email protected]> wrote: Hi Jarek,The vacuum from the engine holds the piston up when you apply power.If there is a hole, the piston will sit lower or if the hole is big enough won't lift at all!Either way you will get a restricted fuel/air flow to those two cylinders and they will be out of balance with the other side.A small hole = rough running. A big hole = very rough running. regardsRob Rob Thompson0429 493 828 On Sun, Nov 17, 2019 at 6:56 PM Jarek Steliga <[email protected]> wrote: Greg, Thank you. This means that I was wrong in squarely blaming a tiny little (barely visible) hole which I detected for the engine at times not being able to rev up beyond 2000 RMP. I simply thought the diaphragm kept the piston up for as long as the revs were higher and stayed there. My detective work is back to square one. RegardsJarek On Sat, 16 Nov 2019 at 22:49, Greg Wilson <[email protected]> wrote: The diaphragm helps lifts the needle when you accelerate. Failed or porous diaphragm will cause a lull in acceleration. I.e. If you slowly increase the throttle very slowly you should still get full revs. Ditto if you don’t lubricate the centre tube, which can cause the carby cylinder to bind when it’s lifting. My understanding anyway. Greg Wilson ---- On Sun, 17 Nov 2019 06:02:55 +1100 Jarek Steliga<[email protected]> wrote ---- Hello, In case some of you had this problem, what were the symptoms? Thank you in anticipation RegardsJarek
