# Homeliite EZ Reach String Trimmer UT20778



## Spit (Nov 3, 2006)

Long story...I am working on my Homelite UT20778 string trimmer. It has a 25cc 2cycle engine. It will not idle. I have replaced the gasket that seals the carb to the engine. I have cleaned the carb and installed a carb repair kit. It starts great in choke and will run fairly well in half choke but shuts off when set for run.

I have a couple of problems/questions.... 1. Cause of it not running in run position...I think the carb is clean, I did not remove welch plugs but I can if it's a likely problem.. I did replace both diaphrams and the needle and lever.
I also replaced the gasket that seals the carb to the engine. It seems like the atmospheric vent hole in the gasket lines up okay with the carb and the carb base. I have read on Walbro's repair manual that I might have a leak on the crankshaft seal, or a leaking main nozzle check valve. or elsewhere on the engine. Where and more importantly how should I look for this type of leak. 

2. It has a Walbro WT 640 carb and has a Limiter on the low speed (allows maybe 2/3rds of a turn...and a smooth steel shaft (no screw driver groove) coming out of the high speed. I took it on myself to get the low speed needle out..now I'm not sure how many turns to tighten it to when replacing.

3. Is the High Speed (smooth shaft) threaded and does it unscrew? do I need to cut a groove in it with a Dremel so I can turn it with a screwdriver? It's completely round and flat and smooth..I see no way to grip it.

Any and all help, advice and prayer is welcome..

Spit


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## Deathrite (May 21, 2009)

as has been noted from others on here taking carb cleaner and spraying a small amount around the engine and listen for the engine to bog down... that will give you the general location of any air leak. 
the mixture screw is normally seated (screwed in until snug do NOT over tighten) the backed out anywhere from 3/4 to 2 1/2 turns. normally i start at little over 1 turn out then go from there. 
the kinda large shaft you are talking should not be removed. i have never removed on and normally it is my understanding that those are not to be tampered with in any way. 
soaking the carb minus all the gaskets and other non metel in a cleaner might do wonders for ya. 
good luck


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