ORIGINAL: i7x58
Another update,
I think something was wrong with my WT 456, it will not adjust. I had around a WA120 and I said to give it a try. What I did, I took the spring for pump from the 456 and without making a hole in the pump cover, I just stik it under the membrane, close the carby and span the motor. I did not prime ...nothing. When I span the motor I was able to see how the fuel got to the carb and engine started. It holds a real nice Idle around 1800 , it can go down to 1550-1600 but a bit shaky.On high I got top RPM with Evolution 16/6 8600 RPM. Transition is not that smooth, I have to go progresive on acceleration. If I ritchen the low it does better on mid range. And the setup instructions from Walbro for adjustment work like the book say.Why the Wt 456 did not want to ?
Any way I ordered on ebay another 456 to try it out again. ThisWA 120 has a 7.89 ventury if I remember right. How this...ventury afects the engine. How would you know what to get. does the wentury influence the fuel consumption.
It is any other Walbro carb there with acceleration pump close to this 6.5- 8 mm ventury?
Thank you
Adrian
Love to help you out, but there are limits to what can be accomplished verbally, over a forum. At a certain point, one must be there in personto spot unusual situations that can cause problems. For my money, I don't think the reed valves were sealing. If you had a closeup camera, some pics of the components would help. The "membrane" you refer to is probably the pump diaphragm. Not a big deal, but it helps if everyone, as much as possible, uses common terms on here. It avoids lengthy misunderstandings. In the case of the WT456, the reed valves (they look like little flaps) are punched from the same little sheet as the pump diaphragm. Was yours BLACK on the WT456? I don't think the venturi size is the issue here. Now, you said you put the negative-pulse-spring UNDER the "membrane". That is not the right place. It goes BETWEEN the pump cover and the diaphragm. Not under it. Hope this helps, even if just a little.