String Trimmer won't start

[Marvinator]

Hope I'm in the right place.
Me: Homeowner
Equipment: (aka, Demon Device) Troy Bilt String Trimmer TB32 EC with electric start. I've owned it about 3-4 years and it has begun to have problems starting and running.
I've looked up the carb (WT973) and found Warblo's website and used that to try and get the dang thing working. No go.
Here is what I'm working with. Spark Plug Gap, properly gapped. (.05mm) I'm using Husqvarna 40:1 premix. It has a new filter and new bulb.
I've started by screwing in both the Low and High Adjustments until they are gently seated. Then I pulled them out
2 full turns. No Start. I've tried adjusting both screws either way as much as a full turn and the most I can get is for the engine
to run for a few seconds and then nothing. I'm not really engine savvy, but this thing is kicking my but.
Can someone give me some pointers or tips in getting it running? I really don't have the money to buy a new one.

 

[StarTech]

Try introducing fuel mix directly into the cylinder and see if it will even hit. Also if you have access to a compression gauge the engine compression level. Needs to be at least 100 psi to even attempt to start. If below 100 psi pull the muffler and check the cylinder and piston. It should score free and the piston ring should move a little when poked.

 

[Marvinator]

It wil start and run for about 10 seconds and then runs out. There is still fuel in the bulb, so I know it's pumping through....

 

[StarTech]

Probably going to need to clean and install a K24-WAT carburetor repair kit. Initial setting for mixture screws is 1-1/2 turns out from lightly seated.

 

[Marvinator]

Probably going to need to clean and install a K24-WAT carburetor repair kit. Initial setting for mixture screws is 1-1/2 turns out from lightly seated.

What would this do? sorry, not really familiar with carb repair. what would this fix that is causing the problems?

 

[upupandaway]

the most I can get is for the engine
to run for a few seconds and then nothing.

Before buying a new carb, if it was me, i would get a spray bottle of soapy water and spray where the fuel hoses connect to the carb, where they go into the tank, and the gas cap itself to find if it is blowing bubbles(which it is NOT supposed to be doing) when u prime it. At lease that would eliminate 1 area of the fuel system before u get a carb and get the same problem.

 

[slomo]

Or clean the spark arrestor inside the muffler. I remove those those, never have a starting/running issue again.Carb might need a new diaphragm too.

Electric start on a trimmer? Never heard of that. Sounds cool.

slomo

 

[bertsmobile1]

The beauty of a 2 stroke piston ported engine is there is no cam or valves.
Thus 90 % of the problems are going to be in the fuel system, 8% will be with the exhaust and 2% the ignition system.

Now the way the forum works is we provide you with suggestions or things to check, and you do these then report back what happened .
We read your results then evaluate your problem & make more suggestions.

There are lots of videos by wanna be experts and some who actually are on 2 stroke theory.
Walbro & Zama both have repair manuals on their web pages with lots of nice colour drawings so you can understand what is happening.
And Walbro have a couplee of videos on installing a kit in their carbs.
I could write 10,000 words here and you would be no better informed.

And whatever you do, don't spray carb cleaner IN your carb.
The fuel channels inside the carb have rubber tipped check valves that are destroyed by std carb cleaner
Walbro hae formulated a new brew that is safe but it costs about the same as a new carb.

 

[Marvinator]

Slomo: Hadn't thought of the spark arrestor. I carefully looked up on line how to take the Trimmer apart, and after an hour and a half I discover that the spark arrestor is built into the sealed Muffler. LOL I'm going to get it cleaned up and back together and maybe try adjusting it again. Maybe tomorrow...maybe not.

 

[Marvinator]

Initial setting for mixture screws is 1-1/2 turns out from lightly seated.

Today I put the whole thing back together. I got to tell you, I really didn't expect it to work well at all. I kinda felt like a kid taking apart daddy's car with no idea how to put it back together. When I was done, @StarTech, your note made the difference. I started again from scratch with only 1 ½ turns and began working from there. Didn't take long and I was out cutting weeds. I hope it continues to work, but if it doesn't at least I know where to start again.

Again, thanks for all your input!