# Simplicity Sunstar 20 Hydro Retirement. What to do?



## JWMUSTANGMAN (Aug 26, 2021)

I've got a simplicity sunstar 20 Hydro that I suspect to be early 90's mfg date. It has served me well for many years as a mower. I have used it exclusively for mowing. It has the 48" deck. deck works good and the mow finish is actually pretty decent too. Early this mow season, it developed an oil leak. It's progressively gotten worse, but I keep it full and it has not affected the performance other than some smoke from the oil burning off the motor. Unfortunately, the Governor seems to have let go now. I was mowing away and it just started revving seemingly out of control all of a sudden out of the blue. I shut it down and started inspecting stuff. All throttle linkage is intact, return springs, etc. Governor setting is correct per the manual. If you open the throttle it just seems to rev seemingly out of control. I'm confident that I f I let it, it would blow. I have not allowed it to rev out of concern for that. I have done some reading up on it, and it seems the "governor driver" (what I call it) down inside the crank case breaks sometimes and can cause this. Fixing it would require going deep into the engine, and I just am not up for that right now. I tried adding an extra return spring and some other little tricks, but to no avail. I could only mow with it if I feathered the throttle with my hand the whole time to keep it from over revving. 

All that to say, I (reductantly) took the plunge and replaced it with a zero turn for mowing. Question is, now what to do with the old sunstar? It's an incredibly well built machine. the horizontal shaft engines are not easy to come by around here, so a used replacement engine is not gunna be easy to locate. It isn't really worth the investment to me to buy a new replacement engine for well over a grand. I wouldn't mind fixing it for a backup, but I don't really have a ton of money to sink into it. I have contemplated selling it, but I honestly would prefer keeping it in some capacity. 

What have some of yall done with "retired" old garden tractors? If I did sell it, what would be a reasonable price? I know these are tanks and were super expensive in their day, but what is a still operable good condition complete used one with a tired motor worth? 

Thanks in advance.


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## bontai Joe (Sep 16, 2003)

WELCOME to the forum! Glad to have you here. I've got 4 old tractors, so I'm not a good person to ask about selling one. I'd be inclined to take your tractor to a small engine repair shop and see what they might charge to fix it. It's usually cheaper to fix one before it over revs and something serious breaks.


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## Bob Driver (Nov 1, 2017)

If it has the M20 Kohler opposed twin, the engine is worth quite a bit. They are hard to rebuild and the parts are pricey, but they are also hard as hell to find used that still run. Parts/machining to do a complete rebuild will run over $1,000 and it's not these easiest engine for an amateur to attempt to rebuild. I've seen "core" prices on a M20 as high as $500, so you can kind of project what the cost of a long block, or complete rebuilt engine would run.

A governor pin failure was the most common failure on the M series of Kohler engines. There was a Kohler Service Bulletin/Campaign on it, but that was years ago, so I don't remember the SB#..... Sounds like what has happened to yours


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## JWMUSTANGMAN (Aug 26, 2021)

Bob Driver said:


> If it has the M20 Kohler opposed twin, the engine is worth quite a bit. They are hard to rebuild and the parts are pricey, but they are also hard as hell to find used that still run. Parts/machining to do a complete rebuild will run over $1,000 and it's not these easiest engine for an amateur to attempt to rebuild. I've seen "core" prices on a M20 as high as $500, so you can kind of project what the cost of a long block, or complete rebuilt engine would run.
> 
> A governor pin failure was the most common failure on the M series of Kohler engines. There was a Kohler Service Bulletin/Campaign on it, but that was years ago, so I don't remember the SB#..... Sounds like what has happened to yours


Thanks for your reply. I don't think this is the "opposed" twin. It's the v-twin. The label says its a CH-20S. Horizontal Shaft, v-style "kohler Command" 20 hp. How hard is the Governor pin to replace? Like I said, other than an oil leak, it runs great up until this governor thing.


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## Bob Driver (Nov 1, 2017)

It's no major deal.... Just have to pull the pan and the governor is right there. A complete governor runs about $35. Kohler part # *24-043-12-S*. Most of Kohler bigger V-twins run that governor. 

Kohler V-Twin Governor

Kohler CH Service Manual


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