Jonsered 52/ won't fire/no gas

[ba_50]

Hi,

I've got a Jonsered 52 with spark but doesn't get gas to the plug. It has a new carb kit and I soaked it in Gunk's carb cleaner all day and night. Then I squirted cleaner through the holes. Some came out into the venturi. There is gas in the carburator. The diaphram's knob is connected to the float needle lever. The back of the float needle lever is level with the casting.

Even when I squirt carb cleaner in the plug hole it won't fire. It has compression because about 8 pulls wears me out.

Does anyone have any idea what is wrong with it? Thanks. Bob

 

[SawTroll]

Std first answer to such q's - did you check the tank vent?????

 

[dtnodya]

Is any fluid coming out of the muffler (carb cleaner, gas)? I'd start by checking the vent as mentioned and then I'd take the plug out and let it sit for a while ... When you spray carb cleaner into the plug hole and try to fire it up, if you take the plug back out what does it look like? Is it just wet with clear fluid or is it dark?

Also make sure that the idle screw is in to where the butterfly is cracked open some.

 

[jonseredjohn]

Try this. Dribble a small amount of premix down the carb throat and attempt to start. If it fire/runs for a few seconds, its a fuel problem,if not its compression,or possibly a substantial air leak.Is there fuel in the pulse pump of the carb?If not you have either a bad fuel line or pulsating vacuum is not getting to the carb. Vacuum reaches the carb on this model via a port in the intake manifold.Check the gasket between the carb and manifold.This is assuming the diaphragms are good and assembled in the right order.Is this saw
a 52 or a52E if its a 52E,it is possible the flywheel key has sheared throwing
the timing off.Happy hunting.

 

[Hard Knocks]

Try to spray a BIT of premix into the carb with a squirt bottle and see if it fires. Have you pulled the muffler off and inspected the exhaust side of the piston? Did this saw die on you or has it just been sitting around?

 

[ba_50]

Hi,

We bought this saw at a farmers auction so I don't know the history. We did have it running once but it died and that was that.

There isn't any fluid coming out the muffler that I noticed. No, I didn't check the exhaust port. I sprayed carb cleaner into the throat but it wouldn't fire. I took the vent hose off in the carb area and blew through it. The gasket between the carb and manifold looks ok. There was gas in the carb when I took it apart but not sure about pulse pump area. I can check the idel screw to crack the Butterfly valve.

I used a compression gauge that doesn't have the bicycle type end on it. It had the same reading as my lawnmower which runs great.

 

[Hard Knocks]

Carb cleaner may not always work to get an engine to fire. Your best bet is to use premix. I would check the piston before going too much further. If you are getting fuel to the carburetor it should at least fire with the choke on.

 

[ba_50]

Ok I checked the exhaust port and it was clean.

Wha do you mean by checking the piston? I could see the side through the exhaust port and it had a few light scatches, but nothing bad.

 

[Hard Knocks]

Checking the exhaust side of the piston is one of the first things that you should do to a non/poor running saw. The piston should be smooth and the ring(s) should be free and springy when carefully pushed in with a small screwdriver. When a two cycle engine is damaged due to heat or poor lubrication it almost always shows up on the exhaust side of the piston. The rest of the piston runs cooler due to being exposed to the cool fuel/air mixture and is much more forgiving.

Were you able to squirt some premix into the carburetor or into the cylinder?

 

[dtnodya]

Carb cleaner may not always work to get an engine to fire. Your best bet is to use premix. I would check the piston before going too much further. If you are getting fuel to the carburetor it should at least fire with the choke on.

Starter fluid works every time also ...

If the saw has compression and a spark then you could take the carb off, spray starter fluid/premix in, and it should fire then die.

 

[ba_50]

Yeh I put gas in a few times and it won't fire. I still haven't checked the ring itself but compression feels good. It ran once when we first got it.

I've had the carb out about 25 times and it is getting very old!

 

[dtnodya]

I'm not saying to take the carb back off ... I was just trying to say that it should run without a carb if it has good compression/spark.

 

[Hard Knocks]

ba_50, An engine needs three things to run. Ignition, Compression, Carburettion.
You have got compression (a reading from a proper tester would confirm this for sure) and you have confirmed that the exhaust side of the piston is not melted down. It would still be good to get an actual compression reading.

You have eliminated the fuel system by manually feeding fuel. The engine should at least fire by doing this even if it has a massive air leak.

You have got spark. How did you confirm this? Did you use a spark tester?
Did you happen to check the flywheel key to make sure that it has not sheared and allowed the flywheel to move out of time on the crank?

 

[ba_50]

I just thought I would mention it about taking it apart so many times. Really getting tired of it.

I checked spark by laying it alongside a ground and pulling the handle. I've got a tester which I will try to see if it will jump or not.

Still can't figure out why the plug isn't wet. Maybe I will put the old diaphragm back in when I get back to Illinois.