Tecumseh/Lauson Carburetor Adjustmen

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Kristof

Kristof

New Member
Jan 21, 2011
232
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0
Aliso Viejo, CA
Hi,

I need help adjusting this old carburetor. I have found an "H" on it, but I have not found an "L". I dont know which screw is which, but Im guessing the one the right is "High" mixture or "Main" mixture?
(The one on the left is actually bigger than the one on the right.)

So far the engine surges at idle and at full it pops really loud.
Are there any instructions on how to adjust this carb. or at least diaphragm carbs.?

https://lh3.googleusercontent.com/_t5uyKe3qmIs/TV3bhHWtjAI/AAAAAAAAAWs/U8jKsRVP0vw/s912/IMG_0060.JPG

https://lh3.googleusercontent.com/_t5uyKe3qmIs/TV3bhe6UnxI/AAAAAAAAAWw/5WYJNU4F2Es/s912/IMG_0061.JPG
 
C

curtisfox

Well-Known Member
Dec 29, 2008
6,046
3,949
113
minesota
Looks like the front would be the high. Turn the high in all the way untill it stops then back out about a turn and half try that. Final is the fastest rpm you can get with the throtle partly open and open a quater turn more. The other should be ajusted so that there is no hesitation between idle and high rpms..........Curt
 
Kristof

Kristof

New Member
Jan 21, 2011
232
0
0
Aliso Viejo, CA
I tinkered around with it yesterday, but no luck. Is it possible that the diaphragm has become stiff? The engine has been sitting around for around 12 years, but no fuel in it though.

Related question: How do I hook up a throttle to this thing? What kind of a throttle do I need?
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
You can get a kit for this carb from a small engine shop. I can just about assure you the diaphragm is shot. The H needle is the high side, adjust @ WOT for max power, adjust the other needle for smooth idle and transition. You generally have to work them both towards each other so to speak to get a properly adjusted carb. These were generally seen on the 3-3.5 engines.
 
professor

professor

New Member
Oct 14, 2009
500
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Buffalo ny area
WOT is wide open throttle. Throttle depends on wether or not you want the governor working. If you don't want the gov. just hook up your throttle cable to one of the holes in the throttle on the carb- you will need to adapt something like the hard wire to a flex cable
I braise a brake cable type clamp onto a bit of hard wire and send the flex wire thu it and lock it down - an adapter.

By the way, I suspect you could swap a float type carb off a Techumseh mower or snowblower.
I like the float carbs better- less to fuss with and no diaphram.
The newer carbs have a primer bulb rather than a choke. They do not have a screw type idle speed stop- just a tab to bend ,but neither do they have an idle circut that gets plugged up like the old Tech. float carbs.
 
Kristof

Kristof

New Member
Jan 21, 2011
232
0
0
Aliso Viejo, CA
Could you show me how to link up a brake cable to the governor, I dont seem to understand "flex cable".

I think I will order a new diaphragm, but how do I know which one to order and where to order from?

My model number is unclear: something like 631032 or 634032 or instead of 32 it might be 82.

My serial number was clear: 33610
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
221
63
Colonial Coast USA.
The float carb will bolt on and the direct linkage hook up is basically the same. The float carb is simplier to understand and work with for most people, but the pumper is also a good carb, but it depends on the diaphragm which has a given life span, for proper operation.
 
LS614

LS614

Active Member
Dec 22, 2009
1,236
3
36
CT and MA
Ah, one of those carbs. I have a love hate relationship with the Lauson carbs, I think that is the exact one I have. They are tricky little buggers, and I have spent hours adjusting mine. but I think it is finally working right. I may be able to get you the exact tuning instructions, let me see here ya go http://www.google.com/url?sa=t&sour...QWNBeAOzQ&sig2=l5qJAxnJcwzC5kmYK-rebA&cad=rja try looking at page 20 first, that's what always helps me :) Good luck!
 
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