Author Topic: Jonsered 2040 Turbo over fuelling?  (Read 1316 times)

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Offline JonF

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Jonsered 2040 Turbo over fuelling?
« on: May 27, 2014, 05:00:42 pm »
I just picked up an old 2040 turbo to chop some logs up for winter etc.
I have replaced the carb gaskets and cleaned it all up.  It's a wabco WT289 so pretty common I think.
The saw has a good spark and compression.
The carb is picking up fuel as you can see it running up the clear lines. However it seems to be over fuelling and flooding. If I clamp the fuel line after a few pulls, the saw will run up fine for a few seconds. When I unclamp the fuel feed line, the saw dies.
I have checked the inlet needle and it seems to seat correctly and is held in by the metering lever.
Anyone experienced this before?  I am not sure else to check.
Any help from the experts out there is very welcome.
Jon

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Offline 660magnum

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Re: Jonsered 2040T over fuelling?
« Reply #1 on: May 27, 2014, 08:19:45 pm »
If you have the metering valve diaphragm against the body of the carburetor with the gasket between the diaphragm and the steel cover it will hold your inlet needle open

Whatever, the needle is being held open
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Online jmester

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Re: Jonsered 2040T over fuelling?
« Reply #2 on: May 27, 2014, 08:53:24 pm »
You also need to check you metering lever height. It should be level with the recess for the lever.
http://www.walbro.com/servicemanuals.aspx. Look at the service manual for a wt carb.
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Offline fordfairlane78

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Re: Jonsered 2040T over fuelling?
« Reply #3 on: May 28, 2014, 06:23:39 am »
Is the saw "filling" itself with fuel while it sits? Also a tell as to if the metering valve is closing. They make metering lever tools for both zama and walbro.  2 of the best tools for 2 stroke repair that I have purchased.
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Offline 660magnum

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Re: Jonsered 2040T over fuelling?
« Reply #4 on: May 28, 2014, 09:41:44 am »
I use a pressure tester on the fuel inlet to see if the carb holds about 7 lbs pressure. I release the metering valve to see if it lets the pressure go and then re-seats itself?
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Offline JonF

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Re: Jonsered 2040T over fuelling?
« Reply #5 on: May 30, 2014, 04:58:44 pm »
Thank you for the advice. I will try the suggestions and get back to you.

Offline JonF

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Re: Jonsered 2040T over fuelling?
« Reply #6 on: June 01, 2014, 02:15:27 pm »
So I have checked the gaskets are correct. The metering lever is set at about 1mm below the recess. Still seems to over fuel.

If I give the saw a couple of pulls with the fuel line open then close it, the saw starts and runs ok for 5secs.  As soon as I unclamp the fuel line, it dies.

Should I try changing the metering needle too? Not much else is there?
The carb to cylinder gasket is not great but I guess the pulse must be ok as it is over fuelling it.

The other thing I have noticed is the saw tends to leak some fuel from the crank case screws in the bottom of the housing. Not much but enough to leave a mark. 

Thanks for the help. 

Offline 660magnum

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Re: Jonsered 2040T over fuelling?
« Reply #7 on: June 01, 2014, 02:42:48 pm »
If the needle has a worn ring around the tip it will never seal reliably.
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Re: Jonsered 2040T over fuelling?
« Reply #8 on: June 03, 2014, 06:35:58 am »
Have you played around with you adjustment screws to see if that helps.
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Offline Cut4fun .

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Re: Jonsered 2040T over fuelling?
« Reply #9 on: June 03, 2014, 07:56:57 am »
I had a stihl 029 in that would flood itself  no matter what I did to carb.  Finally gave up on that carb and  put the same new rebuild kit in another carb and all was fine then.  My WAG = I think the seat is causing the flooding, needle seat has ware or something.

You have tried a complete carb repair kit with new needle installed right?  Not just a diaphragm kit.
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