Jonsered 2240

bluthum · April 24, 2020, 05:59:41 PM

About a year ago I felt the need for a small 40cc saw and found a great bargain [haha] on a three year old but never used Jonsered 2240. It was often hard to start but run great when it ran. I haven't used it much, still on the 1st chain but it became progressively harder to start no matter how the carb was tweaked. Carb is adjustable with a splined tool.

Finally it became perpetually hydo locked with fuel before starting so I ordered a new am carb. New carb installed it cranked right up and sounded good. Later that day I tried to use it and nothing, once in a while it will fire a little.

It seems to be leaking fuel some where below the carb, suspects include the tank itself or the tank vent which is well hidden. Possibly the purge line connection to the tank, I don't know.

Would a tank or other leak make it difficult to start? The purge bulb fills and seems to work, all fuel lines seem good and I changed the fuel filter/pickup. Also tried a new spark plug.

Any suggestions would be appreciated. Thanks in advance!

dougand3 · April 24, 2020, 08:53:03 PM

I suspect your fuel lines are not as good as you think. I'd replace all 3. Tank vent leaking won't cause a hard start but bet it's a fuel line leaking.

bluthum · April 25, 2020, 02:26:38 PM

If the fuel lines are bad I can't see it. They are pretty viewable.

But while pumping the purge bulb to examine the return line I see a tiny drop coming out the seam in the fuel tank right below the trigger. And another. That area of the tank has been showing signs of fuel residue for a while but I ignored it.

Looking inside the tank you can see a big seam of plastic where the two halves were fused together and it looks sound but you can't see the backside. Outside the tank appears to have a very tiny crack around where the drop forms.

But would a cracked tank cause near impossible starting? Any other suggestions for what to examine?

I'm not sure how much I want to invest in a consumer grade saw, but this li'l guy is fun for small stuff, when it's running. Thanks for any more suggestions in advance.

bluthum · April 25, 2020, 02:30:10 PM

Oops I just reread dougand3 's comment that a cracked fuel tank won't cause hard starting. Makes sense. I have plenty or fuel line, is it feasible to make a return line with plain hose, the originals are molded. Other ideas welcome too.

dougand3 · April 25, 2020, 08:52:07 PM

Feel your hoses - they tend to get soft and collapse under vacuum.
544128601 fuel hose - search ebay and see both fuel and return line for $12 w/ US seller.
I normally do Tygon replacement but here - if you have a big tank hole for molded line, you gotta figure a grommet to seal.