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carb settings


racer's Avatar
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03-01-03, 02:52 PM   #1  
racer
carb settings

I'm working on a husqvarna 35cc ice auger and it has a diaphram carb on it. He emptied out the old gas from a year ago and filled it with fresh gas and it fired right up and then it stoped and won't start again. He said it will run by squirting gas in the carb. How do you set the high and low speed screws on this carb? Do you think it's the diaphrams causing this or just a dirty carb? How can you tell if the diaphrams are bad?

 
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03-01-03, 10:40 PM   #2  
Probably just a dirty carb..there's a screen inside that can clog really easily. Bad diaphragms will be noticeable when you get them out and look. If there is a pinhole or wear marks or cracks, or if it is stiff, replace it. Set the low speed screw by turning it in until it lightly bottoms, then back it out 1 1/2 turns. Same with high. This should get you running, and probably a little on the rich side. Fine tune from there, adjusting low at low rpm, and adjusting high at full throttle.


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03-02-03, 06:15 AM   #3  
racer
Thanks cheese I will clean it up and give it a try.

 
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03-02-03, 12:04 PM   #4  
racer
I took the carb off to clean it and the diaphrams are really stiff and i tore the gasket getting it apart so I think I will go and get a rebuild kit. I have another question. When i took the carb off the gas was running out the gas line but when I take the gas cap off it will stop. Is this normal? the vent is not blocked because I checked that right away. Before I took it apart it fired up and I opened it wide open but when I let off the gas it just died. There was alot of gas running out of the carb would that be caused by the diaphrams being bad or what causes that?

 
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03-02-03, 12:14 PM   #5  
Could be a stiff diaphragm holding the needle open, a hole or crack in a diaphragm, or a dirty/leaking needle. It is normal for the gas to squirt out the line with the gas cap on. The vent doesn't allow air to escape the tank on these. It only allows air to enter the tank.


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03-02-03, 12:24 PM   #6  
racer
Do you need the screen in the carb? I can't seem to get the screen really clean or does it come in the rebuild kit?
Thanks for making this a little bit clearer for me cheese!!!!!!

 
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03-02-03, 04:20 PM   #7  
mikejmerritt
The screen will come in a full rebuild kit....Mike

 
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03-05-03, 04:20 PM   #8  
racer
I cleaned the carb and installed a rebuild kit and it fired up. I turned the H and L speed screws out 1 and a half turns and it idles ok but it takes a while idling before you can open it up. If you go to hit the throttle right away when you start it up it will just die but if you let it warm up it will run fine and open right up. Is this normal with this engine or is there something I am doing wrong? What can I do to solve this problem?

 
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03-06-03, 12:54 AM   #9  
Back the high screw out another 1/4 turn and see what it does. You are running too lean at high speed. You want a little bit of "roll" (sort of a slight sputter) at full throttle instead of a whining super high-speed sound. Too lean a mixture will let it fly, but burn up the engine in the process.


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03-06-03, 02:44 AM   #10  
racer
Will backing out the h speed screw help it start better and warm up better?

 
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03-08-03, 01:29 AM   #11  
Yup...it can help with both starting and cold operation, however, these things do require a small amount of warm-up time (10-15 seconds) while holding the throttle wide open and the choke 1/2 on. Backing out the low speed screw can help too, if it needs it. If it seems to be running too lean at idle, but backing out the L screw makes it stall, idle it up a bit.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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