920 Jonsered problem

[Madsaw]

I have a 920 that I am working on to ship to a another AS member. When I got ti in it had a issue of dieing out after about 3 to 4 hard long cuts. Just like it was running out of fuel. Not a problem. changed carbs with one here. Ran good for sometime. But, then doing a finally check on it before shipping it was back to its same old thing. Now today I took it with me to do some work. I limber with it for almost a full tank. Not constant wide open running alot of idling. Quick buzz and idling again. Does this seem to be a weak diaphragm caused by ethanol fuel? If so this would explain the time to kill the second carb. Its starts and idles great lots of power till it runs out of fuel too. And that would be the best way to put it. Just like your on the end of a tank of fuel.
Thought about rebuilding the carb to see how that works. But, the local stihl dealer changed hands to a guy that runs a atv shop. LOL no clue when it comes to saws. How does the governor work on the Tillie carbs too.

Later
Bob

 

[Paul61]

Bob,

This may sound dumb but................check for a plugged vent line form the tank? What happens when you open the fuel filler just after it dies.........is there a vacuum?

 

[Madsaw]

The vent and fuel line all will be removed tomorrow and check. It does not seem to have a vacuum or pressure when you crack it open. But just let it set about 15 20 mins and she is good to go again. For as long as it ran today kind of rules out the coil.
Later
Bob

 

[Paul61]

My little 2050 jonsered had a pinched fuel line, would lean out but only intermitantly. When I found the problem I realized that the prev. owner had drilled a small hole in the cover so he could get @ the fuel line without disassembly! DUH..:jawdrop:

 

[havvey]

920

COULD BE A:biggrinbounce2: N IGNITION UNIT GETTING HOT!!

 

[Madsaw]

Yeap thought about that unit today. It was running for close to 1/2 hr today before it acted up. But, if it is in full cut wide open only takes a few cuts to get it going. Iam hopeing to get to the bottom of it soon.
Bob

 

[Madsaw]

Found It

Well after checking the coil with a new husky coil of the same brand, still the same thing. When all said and done I changed the spark send at the flywheel, fuel line, filter, tank vent and line, rebuilt the carb, changed plugs, and it all boiled down to this nasty little guy. The impulse line. It was so old and hard it cracked but by the cylinder it was really soft and would not hold a good seal on the barb. Replaced that and the saw runs great. All I can think of it that when it rubber got warm the crack got bigger and killed the impulse to the carb.
Thanks for all the ideas.
Bob

 

[bama]

I just replaced the impulse line on mine yesterday. Same deal except I hadn't had a chance to run it, yet. I planned on replacing all the lines this year since they were starting to show cracks.

 

[Madsaw]

Yeap it sure had me fooled. It acted just like the classic bad hot coil deal. But, at least now I know I can sub another model of coil in the saw with just a little bracket to hold it. I put the good old coil back on it. Now I am kind of glad I got a couple of big boxes of NOS husky parts around here.
Later
Bob