# John Deere SB-14 with Kawasaki engine



## moparkansas (Aug 27, 2007)

This mower is an oldie but a goodie and I am trying to keep it going. I just had the motor rebuilt last year, but the governer and carb are driving me nuts. It threw the choke spring and I figured out what was wrong, but now the governor seems to be getting stuck as it activates and I guess it must flood the engine out? It starts and runs well but when it gets a load on it and the governor kicks in it starts backfiring through the carb and dies. I can keep it running if I throttle back but when I put a load on it again the same thing happens. What pulls the governer back when it is no longer needed? I don't really know how best to explain the problem. Also there are three screws the carb. One at the bottom of the bowl - drain one right above that one wihich I think is the mixture and one that controls how far the butterfly opens? How should each of these be set? Except the drain one - I think I have it figured out. Thanks for all the help!


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## 30yearTech (Sep 14, 2006)

It could be any number of things, valves, ignition, spark plug.

Post the model and spec for the engine on your John Deere, maybe we can narrow it down.


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## moparkansas (Aug 27, 2007)

It is a model # 14SB 
Serial tag reads as follows:
serial #GX14SBX059578*
21" mower
JD906

Any help that can be given is appreciated. I just moved and used to take it to a guy I trusted, but I don't know anyone around here.


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## 30yearTech (Sep 14, 2006)

Ok, I am betting that you have an FC150 series Kawasaki engine on your mower. Most likely the cause of your problem is in carburetor. I don't think it's related to the governor, but rather when the governor tries to accelerate the engine you experience the problem.

Based on my experience with this engine, your carburetor is probably not feeding enough fuel to the engine to run under load. 

Before you start messing with the carburetor though, you might just want to try a new spark plug, as one that has a lot of carbon build up can also cause your engine to act this way. If a spark plug takes care of it, then you should check your air filter element and make sure it is not plugged with dirt or soaked with oil, and check the choke linkage to make sure the choke is releasing all the way.

If a new spark plug does not make any difference then I would remove the carburetor and inspect it for dirt and or gum/varnish build up.


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## moparkansas (Aug 27, 2007)

I replaced the spark plug and it is no better. I looked at the carb. three weeks ago when this whole thing started, and it was really clean. The motor probably has less than 20 hours on it since it was rebuilt. When I first started it up today with the new plug, it ran fine for less than a minute, then the governer kicked in, it died, and it was hard to restart, and each time after that the governer kicked in, it died again. 

Where do I begin?


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## 30yearTech (Sep 14, 2006)

Well there is also the possibility that the flywheel key may be sheared. It's a steel key, but I have seen them sheared before. If you feel confident that the carburetor is in good shape, then I would look at the key. If it's sheared it will alter the ignition timing and that could cause the engine to backfire, die and be hard to start.

To answer some of your original questions. 

This carburetor is not adjustable except for the idle speed stop screw, and this is not a mixture adjustment.

There is no adjustment to limit the travel of the throttle, the governor will open the throttle wide open if needed to try to maintain operating rpm's, the governor spring actually opens the throttle and the internal governor assembly closes the throttle as the engine operating rpm's are achieved.


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## moparkansas (Aug 27, 2007)

I didn't have a chance to mess with it this weekend, but I don't think the key is sheared because it starts perfectly everytime when the engine is cold. It is only after the governor kicks in that I have a problem. I can make about a thirty foot pass on the grass before it dies and becomes basically inoperable. If you think it is really the key, I will take it apart, but do you have any other suggestions.


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## 30yearTech (Sep 14, 2006)

Well, I am just spouting out ideas because it really sounds fuel related to me. Try running it with the fuel cap loose, perhaps the fuel cap is not venting and causing it to run short on fuel. Also check for spark right after it dies, it's possible you may have a problem with the ignition module. You are right though, if it starts easy and runs good initially, then it's probably not the key.


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## moparkansas (Aug 27, 2007)

Tried loosening the cap previously. The vent on it is pretty simple. Rubber gasket with a foam insert. Don't think it is the problem. Hmmmm (scratches head). What is the best way to test for spark? I am with you though - I think it is fuel related. It seems to run fine until the governor starts governing. I've watched it happen as the governor moves forward it sputters and dies. Why would it not restart after this happens though? If it were not getting enough fuel wouldn't it restart OK with the throttle moved back? Just throwing stuff out - never had a mower with a wierd problem like this and I hate to give up and (God forbid) pay someone! I think I will go start it again and then check the plug to see if it is dry or wet when it won't start again. Thanks for all the suggestions.


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## 30yearTech (Sep 14, 2006)

The governor is always working. I think you notice it more when it dies because when the engine starts to stall the governor does not know why the engine is slowing down and simply tries to accelorate it back to speed.

To check for spark, remove the plug and with it plugged into the spark plug lead, ground the plug to the block and pull the rope and see if spark jumps the gap. Make sure the engine is on, either with the throttle or control lever, whichever type your mower has.


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## moparkansas (Aug 27, 2007)

I started it and ran it at various throttle positions for about 5 min tonight. I pushed forward on the governor linkage and the RPMs increased as it pushed back against my hand. All of a sudden it quit pushing back against the force of my hand it went all the way forward and the engine sputtered and died like it has been doing. The travel was about 1/4 of the overall travel of the linkage when it quit pushing and died. So what would cause this?


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## 30yearTech (Sep 14, 2006)

Lack of fuel, if the carburetor leans out too much, then the throttle will open all the way as the rpm's decrease and then the engine will die!


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