HT 56 won't start

[mikec35]

I've got a 3 year old pole saw that I can't start. It has progressively gotten harder to start over the years. I put fresh gas in it today and it sputters like it's going to start but it just won't run. I bet the saw doesn't even have 2 hours total run time. Any suggestions as to what to check? Thank you

 

[StarTech]

Doesnt matter on low usuage hours. Rubber parts in the carburetor still ages the same. Most likely you are needing to rework the carburetor. Also check the spark arrester for carbon clogging if present.

 

[bertsmobile1]

Unless you tipped the fuel out & ran it dry the last time you used it then the carb will probably be gummed up from evaporated fuel
The holes in these carbs are only a few thou at best
If it is a later model with a rotary valve carb then the high speed check valve sticks closed
In most cases these are not repairable I have spent hundreds of hours boiling these cube carbs in all sorts of solvents with little luck.
So get a new carb .

 

[StarTech]

Besides Bert it should have a Zama C1M carburetor. The problem is getting any repair parts for the carburetor as Stihl has a stranglehold on Zama now here in the USA and any repair kit for the carburetor is nearly as expensive as a new carburetor or at that is the case here. The full repair kit is PN 7010 871 0205 from Stihl that if the local dealer can even get it. The 4241 007 1700 is just a GND kit.

 

[billypumper]

I had the same problem you have, mine the spark arrestor in the muffler was clogged, this can be removed, I on the other hand chose to use Stihl premixed gas this killing two birds with one stone, keeps the carburetor clean, and keeps the soot from clogging the spark arrestor, which in turn keeps it from starting, Stihl premixed gas is for equipment that doesn't run every day or very often.

 

[mikec35]

Thanks for the replies, I'll check the spark arrestor and I am going to change the spark plug, I think I tried a different one last year but honestly cannot remember for sure. If neither one of those fix it then I'll look to take the carb off and try to clean / rebuild it.

 

[billypumper]

You can run the pole saw with out the spark arrestor, ethanol in gas is the worst thing, especially two stroke, ethanol draws moisture into the tank, hard on a two stroke carburetor, most stihl can gas is ethanol free and 96 octane.

 

[mikec35]

It was the spark plug. I took it out and grounded it and it sparked, but evidently it wasn't enough. Replaced it and it fired up first pull and runs great! Thanks for all the advice.

 

[bertsmobile1]

Modern fuel which is not petrol is very conductive at cylinder pressure
So once wet the plug can allow the spark to track down the side & not jump the gap
The only fix is to get the plug hot enough to burn the fuel deposits off
You will probably find that if you put the old plug in it will run just fine.
If you starve the engine off the last couple of very lean burns will clean the plug .

 

[StarTech]

Must have been a NGK CMR6 10mm plug. I have seen a lot failures of those. I even had one to cause a hedger to diesel.