Husqvarna 235/236 and 240 carburetor problems

[jdvsn83]

Hey guys!

I wanna ask you whether or not exist a tricky fix to 235 and similar ZAMA C1T fuel delivery problems... I receive tons of these saws in my shop and 9 of 10 have the same problem. Replacement carbs here in Argentina aren't an option due to their cost so I end dismantling a lot of these saws.

I tried to override the accelerator pump mechanism as we do on Stihl 201T with no succes.

All lines are new and pressure tested. Tank vents are working fine. All saws are pressure and vacuum tested with no leaks...

When I start these saws i can see small air bubbles going from carb to the fuel line. Carbs are pressure and vacuum tested and they have no leaks.

Any help will be welcome!

 

[PogoInTheWoods]

I'm also curious about the same issue. I'm guessing an impulse issue or something with the purge arrangement or both. I have a like new 235x-torq that will not run. Period.
New carb. Vac/pressure tested good. 150 psi compression. Getting fuel (so it seems -- plug is wet and I can see it in the fuel line). Spark you can weld with. Here's what Husky says for carb adjustments....

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I know on some of these e-lux saws like the PP5020 the adjustments can be all over the map..., as in 2 1/2 to 2 3/4 turns out just to get one started. Been there done that. Just can't make this little 235 fly for the life of me.

 

[jdvsn83]

I'm also curious about the same issue. I'm guessing an impulse issue or something with the purge arrangement or both. I have a like new 235x-torq that will not run. Period.
New carb. Vac/pressure tested good. 150 psi compression. Getting fuel (so it seems -- plug is wet and I can see it in the fuel line). Spark you can weld with. Here's what Husky says for carb adjustments....

View attachment 596184​

I know on some of these e-lux saws like the PP5020 the adjustments can be all over the map..., as in 2 1/2 to 2 3/4 turns out just to get one started. Been there done that. Just can't make this little 235 fly for the life of me.

Impulse issue... That's interesting. I managed to get 1 of 3 running with the accelerator pump override, but its carb kit came with a teflon pump diaphragm.

If I put the acetate one in it, it won't pump gas with the choke disengaged, always talking about same saw and same carb.

Then I put the same carb in another saw, with the teflon pump diaphragm and it'll run flawlessly.

I'm searching for more teflon kits, but it seems to be very tough here in my country.

 

[PogoInTheWoods]

Please enlighten me on the teflon kit. I'd like to eventually find a solution for the problem. Have not messed with the accelerator pump and probably will leave well enough alone there.

 

[jdvsn83]

Teflon pump diaphragm is tan or light brown. It pumps more than acetate and is very common in other kits, but not so common in gnd-83 kits...

 

[PogoInTheWoods]

I always thought they were all mylar in different colors for different thicknesses..., which would probably dissolve over time now that I think about it.

So what is the accelerator pump modification you mentioned? I may as well try it, eh?

 

[jdvsn83]

You have to dissasemble the carb. It's behind the throtle shaft. There is a spring and a piston with an o-ring. To override that sh*t you have to put JB weld inside and then put the piston without o-ring. You must discard the spring too.

But here comes the tricky part. With some acetate pump diaphragms it'll be more difficult to pump gas...

That worked in 2 of 3 husqvarnas with C1T carb. Now I'm trying with the 3rd, but it have an aftermarket carburetor and it doesn't seem to work. However I have another OEM carb and will try with it.

 

[PogoInTheWoods]

Thanks for the detail. Sounds like the C1Q fix for the 200T carbs. Need to do one of those soon so will do them both while I have a small batch of JB mixed up. Will report back on the results.

 

[jdvsn83]

Thanks for the detail. Sounds like the C1Q fix for the 200T carbs. Need to do one of those soon so will do them both while I have a small batch of JB mixed up. Will report back on the results.

I'll be waiting for your results. Take in mind Husqvarna 235/236 and 240 have lots of problems like bad tank vents and vaporlock. They're ****...

 

[SEAM]

One series of saws I do NOT touch any more... got better things to do than trying to fix unfixable stuff.

 

[jdvsn83]

One series of saws I do NOT touch any more... got better things to do than trying to fix unfixable stuff.

I'm going in that direction too.

Some 235, 236 and 240 have air leaks in carburetors, specifically in their accelerator pumps, and this problem is perfectly fixable. The "unfixable" ones develop some kind of air leak in other parts when hot, or they just lose compression, or maybe that weird plastic transfer inserts become loose when hot... The problem is to identify wheter they're fixable or not before wasting our time...