I am having trouble with my WT-731 carb.[:'(] I can get the engine to start and run from mid-range to Top end. I can't it to idle. [:@]I have replaced all of the seals and diaphram's and it still won't idle.[:'(] I have installed a choke and I have to keep the choke at half just to keep it running at all. I would like to get a new carb, but the WT-731 that is on the engine is no longer avalible. I have tried a WT-433 and a WT-622, but I cannot get them to even pull fuel into the carb. The pulse from the engine to the carb is working just fine. Does anyone know what Walbro carb I can use on the SV-26 or what is the Walbro carb the new SV-26 enignes are using?