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Discussion Starter #1
This is a carb from my Briggs and Stratton 3hp, Mod # 81302 Type # 943563, SN 5903060. I think it has major issues. The engine idles with it, but when I move the throttle linkage it does nothing. It will only run with the choke closed up tight. If I crack the choke at all the engine will begin to rev and die. I have noticed that it idles and runs great while the choke is closed. No smoke.

If anyone has a Carb like this I'd love the chance to buy it...

Thanks again!!!

Mike.
 

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Sounds to me like something is plugged up, take it apart soak it, spray it with compressed air, and put it back together. Ed
 

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Discussion Starter #3
Ed,

I cleaned the carb, took it all apart... it looked good, it was dirty, used a lot of carb cleaner on if and air. Maybe I need to do it again just incase a little piece of junk got in there.

The carb was off the engine when I got it so I'm not quite sure how the gov. linkage and other works, but it shouldn't be to hard to figure out. The throttle cable was on so I know how that attaches... Any other advise you can share would be good. I'm still quite green when it comes to carbs and linkages...

Thanks again,
Mike.
 

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Hi Mike. eveled is right. You have to completely dismantle and soak everything, and then blow the orifices out with compressed air. Probing the passages with small diameter wire would help also - I use guitar string...luckily my best mechanic friend also plays the guitar. Look on the bright side though, Mike. At least you have a carb to work with; I have a B&S engine with the same carb on my McKissic Leaf Mulcher/Grinder but the casting on the air filter inlet has developed cracks all around the choke butterfly, and is now junk. I don't have another one, and can't seem to get one anywhere, so my McKissic is now out of commision, with falling oak leaves on the way - just beautiful. If you get everything cleaned out on the carb and reset properly, she will run! PS - careful of the gaskets unless you have spares. Nobody has them here where I amBest of Luck!
 

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I would get a little can of liquid Carb Cleaner and soak it for a day and then blow it out. Soaking will get more than just using spray cleaner. :fing32:
 

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Mike, it only takes a little bit of foreign matter to plug things up, as they say. Something so small you wouldn't notice it. When I assemble a carb after the soaking/cleaning/washing/drying is done, I always do it on a white shop towel on a table in my Liiving Room, not in my garage or shop or basement. My wife really LOVES this, but luckily has gotten used to it over the years, since I leave no mess behind. As you mentioned also the governor linkage has to be right, or it won't work well. I remember a 6hp Tecumseh which I took apart some years ago to rebuild the carb without paying attention to the attached throttle bracket and governor linkage connections/routing, and it took me the better part of an afternoon later to get it right again. I learned my lesson on THAT one. When you get everything right you will know it - suddenly it will work without problems.
 

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Discussion Starter #7
UPDATE!!!

I cleaned the carb a second time. This time the throttle worked and it ran, for a short time with no choke. It's currently sitting in gas soaking. I'll leave it there for a day or two, or however long it's recommeneded to soak... (relying on your advise for that)...

still now smoke... this thing sat for probably 20 years. Sat for so long in fact that the rims rusted out where stuff was packed up against them. I would imagine it take quite some time for a rim to rust through...

Anyway, I'm thinking now the carb I have might do the trick with a little time and patience... it's the patience part that's tricky for me sometimes... haha..

Thanks again Mike.
 

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Mike, I can't recall ever seeing one of these carbs on an engine of your size. That type carb is usually used on the 8 horse and up engines. Smaller Briggs engines with the horizontal crank usually use the vacu-jet type carb. That is the style with the fuel tank mounted directly below and to the carb. Guess we learn something new all the time.

Have to agree with the others. If an engine doesn't respond to throttle changes and carb adjustments, the carb needs a good soaking in carb cleaner. I like to remove the main jet as well, this way the air bleeds around it can be cleaned up as well as the main jet well of the carb body.

Good luck with your project.
 

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Mike, I can't recall ever seeing one of these carbs on an engine of your size. That type carb is usually used on the 8 horse and up engines. Smaller Briggs engines with the horizontal crank usually use the vacu-jet type carb. That is the style with the fuel tank mounted directly below and to the carb. Guess we learn something new all the time.

my D/B has the updraft carb too, 3horse (or something):trink40:
 

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When you have it apart, just look at it really really close and try to visualize where each passage goes to then probe using a small wire. I use one strand of wire out of regular electical wire. I like the copper because I feel like it doesnt' scratch the aluminum. Remember every passage goes somewhere make sure it is clear all the way through. Once you get it running put sea foam in the gas and run it. Good luck, Ed
 

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Mike,

Drop by your local NAPA and pick up a one gallon can of carb cleaner/soak. It comes with a basket that stays in the can and works great. It runs about $20. The carb needs cleaned with a good solvent, and not gasoline. Gasoline has been sitting in it a long time and turned to varnish. The solvent will clean it, gas won't do such a good job.

The can of solvent will last you for years if it is closed up properly. An investment well worth making. :fing32:
 

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Looks to be a small flow jet carb. They are out there, keep checking Epay they do come up NOS from time to time,, the medium and large models seem to be more common though. I have one on an old engine, it has multiple problems, warped halves from over torquing the bolts, bad seals on the emulision tube, its problems go on and on,, so I found a later model Running engine cost me 35 bux to double my power and the new engine starts in 1 or 2 pulls. It's not original. but it is now a working machine instead of a display piece.
 

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there is a passage in the bottom of the float bowl that feeds the main jet. It could be clogged, and you won't see it unless you know it's there. Fill the bowl with solvent, and you should see the liquid drain out where the high speed needle valve screws in. It the bowl holds fuel, that passage is clogged.
 

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I purchased the manual from Briggs that shows all of the old engines, configurations etc... It cost @ $35 and has been very helpful. I think I have that carb on an old torro snow thrower.
 

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I have 3 or 4 Briggs 3 hp horizontals, and all but one has the Flo-Jet style carb. They were used a lot on 3 hp. I only have 1 with a Vacu-Jet style carb, and that engine has a fixed throttle linkage with no way to accelerate except with the governor; it runs a water pump on a sprayer. I still know that if you keep playing with it, she will run Mike. Keep in mind how long you said it must have sat idle without being prepped for the lay-up - a lot can happen in all that time.
 

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Discussion Starter #16
there is a passage in the bottom of the float bowl that feeds the main jet. It could be clogged, and you won't see it unless you know it's there. Fill the bowl with solvent, and you should see the liquid drain out where the high speed needle valve screws in. It the bowl holds fuel, that passage is clogged.
I found that hole you're talking about. I cleaned it out and it ran a lot better. Still not good enough... But I think I'm on the right track with cleaning this thing a little more.

I just went to the auto parts store and picked up a gallon of Berryman's Carb Cleaner... the one with the parts pan in it. I'll let it soak in that for a while... I think I'm still going to have quite a time with the throttle linkage. I'm not quite understanding how the governer flap links into the throttle. As you can see in the images the throttle cable mount is that small bracket under the carb on the engine case. The cable goes directly onto the carb as far as I can tell I'm not sure where to hook the springs... There was another piece I found that is about 6 inches long with a 90 degree bend in it at one end with a couple holes for what look like a spring attachment. I've seen that same think on other carbs like the one I have, I've seen it called the throttle, but I'm not sure how it works. Anyone that could give me advice on that matter, it surely would be welcome.

Thanks again
Mike.
 

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Mike,
There needs to be a link from the governor arm the the carb throttle shaft.

The control cable hooks to the spring that tugs on the governor arm.

A governor tries to close the throttle and the spring/throttle cable tries to increase the throttle openning. The balance between the two is the rpm you end up with.

Garry
 

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Hi all, I'm new to this forum so bear with me if I'm in the wrong place.
I have a Briggs and Stratton with the same carb as this one. Could anyone advise me on the proper procedure for setting up this carb please. Its on a rotovator. Engine details are as follows-- Model No- 81302, Type No- 943756, Serial No- 6103240.
Also, can anyone tell me what type of carb this is please?
The engine will start, but if I close the choke to cold start the engine it wont start.
It will only start in choke open position. All advice will be much appreciated. Also advice needs to be as "idiot proof" as possible please.
Can carb gasket kits for this carb still be obtained.
Many thanks in advance, Glenforkie
 
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