Walbro 688-1 Carb Issues

[MarkyZ]

So I don't own a mower, but I'm hoping you guys can give me a hand. I have an Ice Auger running a Solo powerhead which uses a Walbro 688-1 Carb and am having some issues.

The motor starts fine and idles as well as the day I bought it, however when I open it up to WOT it bogs down and dies. Auger worked fine with no issues, this issue happened randomly and I haven't been able to shake it since.

Bought a rebuild kit and replaced the float diaphragm needle, screens and float diaphragm, no luck.

I tried lifting the needle arm on the float diaphragm side with no luck, motor ran richer(I think) and produced more smoke but still bogged down at WOT. I thought about adjusting the high jet, but that requires special tools on my carb, and it also worked fine for the past 3 years, why would the setting give me problems now?

On the fuel pump side I wanted to replace the fuel pump diaphram, but my carb uses a beige almost mesh like diaphragm, but the diaphragm included in the rebuild kit is black rubber. Will the black rubber diaphragm work?

Any help or advice will be greatly appreciated!

Mark

 

[reynoldston]

On a lot of the small engine its easier and just as cheap to replace the carburetor them mess with the old one.

 

[Rivets]

I'm assuming that you have a WT668. My guess is one of two things going on. Either the power needle needs to be adjusted or you have dirt blocking an internal passage. You will have to decide which direction you want to go. Do not use the black diaphragm unless you took out a black one. Best bet may be to take it to a good chainsaw mechanic, who will work on these units. Many do not want to touch them, because they have no way to test them under load. This breakdown might help.

http://wem.walbro.com/distributors/servicemanuals/WTseries.pdf

 

[MarkyZ]

I'm assuming that you have a WT668. My guess is one of two things going on. Either the power needle needs to be adjusted or you have dirt blocking an internal passage. You will have to decide which direction you want to go. Do not use the black diaphragm unless you took out a black one. Best bet may be to take it to a good chainsaw mechanic, who will work on these units. Many do not want to touch them, because they have no way to test them under load. This breakdown might help.

http://wem.walbro.com/distributors/servicemanuals/WTseries.pdf

I'm going to pop off the cap which encloses the high speed jet and blow some carb cleaner in there. I don't have the tools to adjust the jet using the needle so this is all I can really do for now.

I'd like to repair this myself, as I find fiddling around with the carb super interesting, but at the end of the day if I can't get it working I'll replace the carb. Anyone know where I can get one for cheap?