Thanks all for your contributions, looks like I'm back to square one with this machine, Last year September I pulled the carb and fitted it with Joel's (CM) SS needle & return spring with modified cap to suit,plus diaphragm. When it was over revving I pulled the carby off to discover that there was actually a chunk missing out of the bayonet type fitting where it fits to the manifold.
I stole a carb off a mower I had with a dodgy frame (Victa Rapier) and swapped the new bits into it but used the original poppet as the rapier one appeared different...only 2 settings but a nifty little peg which would have made it easier to change settings, I renewed the O rings to carby, manifold &starter but not the lower bearing one. I was sure this was going to solve all but not so!
I'm not sure which needle is in it but I'm a bit suspicious of the thread where that goes in so don't want to interfere too much with it ffor the time being.
I had a poke around with the air diaphragm but wasn't sure whether to poke the wire right through it...thought it might have a mesh or something in there. @Sapper, is this what you refer to (Engine Venturi pipe) having been cleaned out with whipper snipper line?
EDIT. Just remembered I did put a shorter spring in the diaphragm cap, just for the heck of it!
Danny
Hi Danny,
What I mean is the little stub that comes out of the engine block in front of the fly wheel. So, you have one hose coming out of the carby on the cap, this goes to the engine venturi stub in front of the fly wheel. Just gently take the hose off the stub. Sometimes this can be blocked with junk (somtimes even the hose can be), and cause the engine to scream uncontrollably, even for a while after you change the throttle down to lower revs. Push the wire/whipper snipper cord right through and back again, just in case it was blocked.
CM explains it better than me actually
Possible solution:
1. Clean the governor air venturi with wire and carby cleaner. This air venturi is located on the base of the mower in-line with the flywheel with nozzle connected to the carburetor diaphragm cap.
2. Change the diaphragm. The diaphragm might be getting hardened and stiffer or you might have the aftermarket diaphragm which is hard, thicker and stiff.
3. Change the long spring or return spring with a lower weigh or grams (weight is measured by grams per displacement) e.g. the clear color one.
4. Change the main jet with lower flow rate e.g. 2-rings.
5. Adjust poppet valve setting to low or more restricted when fully closed.
