Good Evening,

I have found many interesting threads up here similar to my own problem but still have not found a solution to my issue.

I have a 6 year old Craftsman Gas Line Trimmer, 32cc weedwacker, with a Welbro carburetor (WT-628).



Recently, it would not stay started and kept dying. I figured it needed the carburetor cleaned (possibly rebuilt) and the fuel lines replaced.

I went ahead and replaced the fuel lines (including fuel filter).

It still would not stay running other than in a mostly closed choke position.

I then took apart the carburetor and cleaned/soaked most of it in carburetor cleaner for an hour. I was going to reuse everything but because I had also soaked the needle - the carb cleaner ate through the rubber tip on the needle and it broke off - so I went and bought a rebuild kit (K20-WAT) from the local small engine repair shop.

I then replaced the needle, the needle assemble (but not the spring - the kit did not come with one), the screen, the pump diaphragm and gasket, and the metering diaphragm and gasket.

When I go to start it, I can prime the bulb a few times, open the choke slightly, and start it. If I open up the choke fully, it will die.
If I start it, again with only partial opening the choke and holding it at Wide Open Throttle (WOT), it will run for about 5 seconds and then die.

I had someone press the primer bulb every two-three seconds and it would stay running but only if they were priming the bulb every few seconds. If I opened the choke up fully and had them prime the bulb every few seconds, it would die upon opening the choke fully.

BTW, I have never adjusted any of the screws...

Oh, one other thing...because I read up here about the spark arrestor being a possible problem, I went ahead and took that apart (Wow, that spring is one tough mother! ) but that looked clean - I sprayed it with carb cleaner anyway and got it back together (Hey, I also got to see inside my engine (Piston, flywheel, etc... - never saw that before! )


Can anyone assist? Here's some more pics.

 

Here's some more pics I have (I guess I'm limited to 10 per post).












Oh, if anyone tells me to adjust that H or L screw(s) - how do you do it? I don't have that type of socket or fitting??? What is that?

 

There's a number of possibilities, but given what you have done, I would give adjusting the high/low screws slightly and see what you you get. Mark them to index the starting point and only go maybe 1/8 turn counter clock at the most. If it takes more than that it's back to some other things.

Geo had the best suggestion for a DIY solution to those little odd ball screws. He used a crimp on wire connector with the size to fit the screw. You normally won't move them often and the connector works well. Just get a cheap selection of them and pick the one that fits.

Try the adjustment first, counter clock, and don't go too far. See if that will do the job. Those little two strokes are pretty fussy, so a little goes a long way.

** BTW nice pictures.

 

Are you talking about something like this?



Which side would I do first? The High or the Low???

 

Yep, those are the things - use the end you put the wire into. Since it quits on you altogether do the low side first.

If it was idling fine, but quit when you open the throttle, you'd go to the high side. Get the little sucker to run at idle first, then we'll go through the whole thing for you.

 

Below is a pic of the connectors. Have a good one. Geo

 

Do I use the fork type or the female type wire connector? I'm going this afternoon to buy them - I don't have anything like that around. Hopefully the set I pick up will have both types. I don't exactly see how the female ones would work...


Also, should I be focused on a fuel delivery problem vice adjustments at this time?
It seems that I can only keep it continuously running when I have someone prime the bulb every 3-4 seconds.

I'll try to record a video of it, put it on YouTube and post a link later.

 

Do the low side adjustment first. Use the end of the connector the wire goes into. The other end doesn't matter. Geo is just using that female connector because it fits his screwdriver for convenience.

Those screws aren't hard to turn, you can hold the connector with a pair of pliers.

 

Ah, now I understand...I was thinking you were supposed to use the fork portion to grab on to the adjustment nut...not the end that the wire would go on to.

I'll post back later - I'm away from the house right now.

 

Before adjusting anything, I took apart the Welbro Carburetor again and made an adjustment to the needle (based upon a video I saw on YouTube about rebuilding a Welbro carburetor.

I was playing with a lot of adjustment to get it started - finally I got it started and running...but I still need to make final adjustments on this Walbro carburetor to get it running in optimum condition.

Does anyone have a guide that could help with setting the H & L settings, as well as the idle screw?
What order is the L & H screw settings adjusted at?
Are the adjustments made at idle speed or Wide Open Throttle???

Finally, how do I adjust the idle screw?

I'm uploading a 5 min. YouTube Video right now of it running. Too bad I had it running for the first couple of minutes with the choke 1/2 closed. But, hopefully someone can better understand what is going on and offer advice.

Here is the YouTube video of it running - the first couple of minutes, I did not know it...but I was at 1/2 choke open.

Thanks!!!!!!!!!!!!!

 

Here's some pics from taking the Walbro Carb apart one last time to double-check everything and to adjust the height of the spring for the needle. I adjusted the height of the spring needle based upon this 3-part video series on YouTube that I found about rebuilding carbs.

 

If you want carb info for walbro carbs go to Welcome to walbro.com and select the Service/Aftermarket tab, you will find lots of info. I always suggest using the old metering arm unless it is very worn as the old one has the proper height setting. Have a good one. Geo

 

Thanks to everyone...I found quite a few web sites out there about tuning a Walbro carb. I followed some of the procedures and this thing is awesome now!

Thanks to geogrubb and marbobj for your insight...you greatly helped this student learn more than he ever knew about a carburetor!

 

after my girlfriends dad came over and looked at it, (he used to do this sort of work for a living) he cleaned out the muffler. he says its pretty common for those to clog up. but after he did that it ran perfect for a while, until i ran out of gas. i refilled and now its running for a few seconds wide open and dying like i shut it off. i need to know which screw is the H and L. ive played with it so much its out of whack.

good tip about those electrical connectors btw! my stepdad found that out before i found this thread.

 

Sounds like you have and air leak or cracked fuel line, check the fuel lines or just replace them to be sure, visit the walbro site for adjustments and stuff. If you can keep it running, dribble/spray brake parts cleaner behind the carb and along the mating surfaces, if the engine tempo changes you have found the leak and can take the appropriate action, the little engines don't like air leaks. Have a good one. Geo

 

If you look at the picture of the screws you'll see the H and L marked. The low is closest to the side the throttle shaft goes through.

 

Pure genius with the crimp connectors! Got mine to stay running with just a 1/8 turn of the high speed screw!
Thanks guys!!

 

JRL,
I am so thankful I found your thread. I am 99% sure I have the same weedwhacker and I do not have enough info to order a new throttle trigger. Would you PLEASE give me the model number of the weedwhacker. There are only a million diffrent models out there and I am pulling out what little hair I have left trying to fix mine..LOL..Thank you - Ric

 

Go to Advance Auto parts and buy a bottle of Sea Foam Motor Treatment for 2 cycle and 4 cycle and diesel engines.. Its amazing..Add as directed to gas ..gas oil.. crank and try to keep it running with the trigger. It takes about ten miniutes before you can tell its cleaning the jets.. My 32cc was doing the same thing..it would crank run a little while and shut off. Its running like a new one now.

 

Nice thread -- and great idea for those h-l settings. Mine runs fine when level/horizontal however when I tilt the unit to actually "cut" my lawn it runs for a short time (< 30 sec.) and then cuts outs.

My best guess is that due to the overly vibrating system it's somehow getting air in the gas line (I can see the gas getting shaken up). Any thoughts on that and if in any agreement anything I can do to stop it? Any other ideas I could try?

I just finished cleaning air filter / rope retractor / spark plug / generally accessible parts with brake cleaner.

craftsman 32cc straight shaft.

Thanks for help!