jairgee

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First, I'm not a mechanic - just a fairly handy homeowner. I hoping someone here might be able to help.

I'm trying to fix my Husqvarna YTH24V48 riding lawn mower with a 44r877 Briggs and Stratton engine. The carb kit, oem part number 593392, works with the B&S "Chok-a-matic" system (which I really like). This carb has a light weight spring and a place to connect a choke return spring. I purchased an "equivalent" carb kit, which works, but every kit I can find seems to work only for a manual choke - it's missing that place to connect the choke return spring and the spring inside is much tighter. It's clearly not equivalent.

The original kit isn't manufactured any more. Does anyone know how I might be able to get the original carb kit (even if it's used)? Or maybe someone has advice guidance for a non-mechanic like myself to convert this mower to a manual choke?

Right now, I have to reach under the air intake and hold the choke with a finger to start the engine every time. It kinda works for me, but it's tough to try explaining that to anyone else who wants to use it, and it's a little dangerous for someone who doesn't know what they are doing.

History:

The mower worked fabulously for quite a few years. Then, we inadvertently bought bad gas with a significant amount of water in it. We flushed out the tank, fuel lines, and replaced the fuel pump and filters. It still did not run right - speeding up and slowing down significantly and losing power. Tried cleaning out the carb to no avail. Eventually, we just replaced the carb with an "equivalent" model and voila, it runs nicely again. However, the replacement carb is for a manual choke and this mower has a chok-a-matic, which no longer works. I tried to disassemble the original carb kit, which was more difficult than I expected, and I may have damaged it in the process. :(
 

Rivets

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Might try one of these sites which say they have an original. Beware Fleabay and Altozon are a crap shoot, make sure you call first or that it can be returned.
 

StarTech

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If I remember correctly this system only assists in closing the choke when the throttle lever is not in full choke position. Try adjusting the throttle cable with the lever in full choke position so the choke is fully closed.

Basically this system is auto choke style system which closes the choke whenever the engine is not running and as the engine starts up it opens up the choke. The replacement choke is a standard choke setup so you have choke the engine and move off choke as it starts.

The control assy is the same choke-a-matic setup for single throttle/choke control cable setup.
 

jairgee

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If I remember correctly this system only assists in closing the choke when the throttle lever is not in full choke position. Try adjusting the throttle cable with the lever in full choke position so the choke is fully closed.

Basically this system is auto choke style system which closes the choke whenever the engine is not running and as the engine starts up it opens up the choke. The replacement choke is a standard choke setup so you have choke the engine and move off choke as it starts.

The control assy is the same choke-a-matic setup for single throttle/choke control cable setup.
Thanks for this! I will have to see if I can adjust the throttle lever. It has a "locked" position at the top that previously would hold the choke closed (or partially closed?) and the throttle at max; very handy for cold and winter starting. That doesn't seem to work with the new carb, but maybe it can be adjusted to do so. That would at least make it easier to get started!

The old carb had a linkage to a "flap" (I'm sure there's a technical term for that) that is pushed back and forth by air flow from fan blades on top of the engine. As the flap moved, it adjusted the choke. This was particularly nice in the winter when we'd use a 48" rotary broom to move snow; if there was a very significant load on the engine (causing it to bog down), it would seem to accommodate automatically by slightly closing the choke (increasing the fuel flow?).

With the equivalent replacement carb, this doesn't happen - at least not in the same way. The engine instead sort of revs up for only a moment, which I'm guessing has to do with the tighter spring. As a result, it doesn't seem to have the same power under load that it used to. This happens similarly when cutting taller or damp grass, and it often can't lift it far enough for bagging. Before replacing the carb, I never had any problems with that.
 

jairgee

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Thanks for this! I will have to see if I can adjust the throttle lever. It has a "locked" position at the top that previously would hold the choke closed (or partially closed?) and the throttle at max; very handy for cold and winter starting. That doesn't seem to work with the new carb, but maybe it can be adjusted to do so. That would at least make it easier to get started!

The old carb had a linkage to a "flap" (I'm sure there's a technical term for that) that is pushed back and forth by air flow from fan blades on top of the engine. As the flap moved, it adjusted the choke. This was particularly nice in the winter when we'd use a 48" rotary broom to move snow; if there was a very significant load on the engine (causing it to bog down), it would seem to accommodate automatically by slightly closing the choke (increasing the fuel flow?).

With the equivalent replacement carb, this doesn't happen - at least not in the same way. The engine instead sort of revs up for only a moment, which I'm guessing has to do with the tighter spring. As a result, it doesn't seem to have the same power under load that it used to. This happens similarly when cutting taller or damp grass, and it often can't lift it far enough for bagging. Before replacing the carb, I never had any problems with that.
Update:
I fabricated a new linkage from the chok-a-matic to the new carb. Now, when pushing the throttle up into the locked position, it closes the choke completely. Although I haven't performed a thorough test, I'm sure this will make a big difference in getting it started, at least. When it stops raining, I'll be able to test it more thoroughly. Thanks @StarTech for this guidance!
 
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