Mower Surges.. Engine or Something else?

rubantin

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First the short vent… I have an old widow friend in my church that has an old craftsman five-speed hydrostatic LT 4000. She usually calls me when she has problems with that stuff, but she knew I was having physical problems at the time so she did not call. I called her on the phone to see how she was doing yesterday and she told me that her old craftsman had been in the shop because the steering went bad on it. She had a small engine shop give her an estimate and they told her that her axle was broken and that it would cost too much to repair it. She asked me if I wanted it. So I thought wow, great, I have one with a bad engine so, I could swap the engine with the bad one of mine. Unfortunately it's only a 12 horsee… And I need an 18.

So I looked underneath as I ws loading it up from the repair shop... the only thing wrong with her mower is the main 5/8 bolt to hold the shaft had lost it's nut. How in the world did a professional miss that?!

Anyways I just bought the nut and I put it on and drove it around my yard for the last half hour with no front end problems.

However, there is a strange thing going on with that mower. Every other second it feels like I'm putting in the clutch and letting and out, putting the clutch and letting it out... Surging, and motor seems to be responding afterwards according to the load instead of causing the problem. Any ideas?
 
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Your carb needs some attention. A good tear apart and cleaning should do the trick......
 

rubantin

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Just noticed something else... when I am going down a slight grade the motor does not change speed but the mower continues to slow and lurch every other second... like somethings going on with the transaxle or something...
 
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Yes your carb is the problem. You did not post what engine you have on there.

The older Craftsman's had the Tecumseh engines on them most of the time. Now it's whatever they find the cheapest.

What you can do is post the Make of the engine so we know what we are up against. Model type code ETC.

It is for sure a fuel problem. Bad fuel lines flapping inside. A clogged vent on the gas tank cap. Carb needs a cleaning. ETC.
 

7394

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If the transaxle is a Dana 6800-1 they have a chain inside them & when worn enough or stretched, it will surge going down slopes. Mine sure did.
 
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Is the engine surging not moving the lawn mower ? Or it just surges when the mower is in motion ~!~!
 

rubantin

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It is a gt6000 with an 18.5 HP Briggs Gold edition... 6 speed manual with high and low gearing.

It does not surge while in neutral... In fact some times when it is doing it's thing the engine does not change at all...
 
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Ok one more thing........... When you are not moving the mower and the blades are engaged what does it do ???
 
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