Buy a new cub or try and fix up my 129 hydrostatic?

three4re

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Hi,

For those familiar with my model, you know that it's virtually all cast iron and steel. The thing has been a real war horse. I've had it for 36 years (I think it's a '72 or '73) and it has given great service. Since this past summer, though, it has not been running well. My brother is a mechanic, and so after I tried everything I could, I gave it to him. We've replaced the carburetor, all new ignition system parts, had the head off and planed / cleaned. It runs absolutely fine sometimes, and other times quite poorly. When not running well, there is a noticeable loss of power and it would be next to impossible to mow the lawn with it when it's running in that condition. I know cause I've tried it and can barely make it back up my sloped yard. The only way I can get anything done when it's running badly is to go really slow and allow the RPM to try and catch up. Still, it just has no power when it's like that. We thought all was fine, however, after putting on the new carb - he used it several times and was going to load it on the trailer to bring it back to me, and then just that suddenly when he started it he knew that it was not running well again. The engine is a Kohler 301. It was overhauled once many years ago but to be honest I'm not sure exactly what was done at that time.

Certainly an option is to purchase and put in a re-built engine, but of course I'd be putting a new engine in a tractor that is still over 40 years old that has a constant (though minimal) fluid leakage out of the transmission. There is a good amount of blow-by, but that would be corrected with a rebuilt engine. I have a mower attachment and snow plow for it that I've used as long as I have the tractor. The other option is to call it a day and just buy a new cub. Where I live, the ability to plow snow with whatever tractor I have is a necessity. I do not know the capabilities of the newer cubs as to attaching a plow and would need to research that. Certainly the idea of a newer tractor with more HP than mine has is intriguing.

Getting back to my brother's repair efforts - I know he wants to unhook the ACS springs so as to do a compression test, and also would like to take a look at the condition of the valves. My sneaking suspicion, however, is that he's just not going to find whatever is causing this intermittent poor running condition. He is willing to put in a rebuilt engine if I tell him to do so, but just feels that it may not be cost effective and perhaps not worth it (?). Old timers' advice on another cub forum wherein I have posted numerous threads about my tractor has consistently been to definitely fix up the 129 rather than buy a new one. The general take I get from some of these guys is that the new ones just won't last as long and aren't built like mine. Hands down, they suggest to keep the old one going. I get that, and indeed have been leaning towards the rebuilt engine option, but I just don't know if that truly is the best way to go. I need to make a decision though since the winter season is coming and I don't want to be without a tractor too much longer.

Any thoughts or suggestions greatly appreciated...

Regards,
Keith
 

ILENGINE

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Something to consider since the engine has been worked on. the old K series engines were bad for blowing head gaskets, and would run fine would cold but would loose power and would even stop running when hot. If the head bolts are not replaced with the head gasket that is one of the symptoms. When the head bolts are initially torqued they are stretched and will mimic the expansion and contraction as the head of the head and block changes, but loose that ability if removed and reused.
 

three4re

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Something to consider since the engine has been worked on. the old K series engines were bad for blowing head gaskets, and would run fine would cold but would loose power and would even stop running when hot. If the head bolts are not replaced with the head gasket that is one of the symptoms. When the head bolts are initially torqued they are stretched and will mimic the expansion and contraction as the head of the head and block changes, but loose that ability if removed and reused.

Interesting...I did not replace the head bolts since they seemed fine. What you're saying certainly makes sense, although the pattern has been that, in times when the engine was not running well, it'd generally improve as it warmed up. Often about an hour after I first started mowing, it'd be running normally with full power.

I might go one step further with this thread and ask...if I were to buy a new cub, are there any particular models that you would recommend? I definitely need something that is heavy enough to plow (sometimes large amounts of) snow. Our driveway can get massive drifts in it so my 129 has sure done its share of pushing heavy, wet snow/ice mixtures. So I'd need something with substantial weight.
 

ILENGINE

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for heavy use and longevity I would go with a XT3 series. the only one of the series with the drive shaft and the ground engagement transmission would hold up to use more than the belt drive and lighter lawn tractors trannies.
 

three4re

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for heavy use and longevity I would go with a XT3 series. the only one of the series with the drive shaft and the ground engagement transmission would hold up to use more than the belt drive and lighter lawn tractors trannies.

Thanks...I believe I had looked at those briefly awhile back on the cub website. They look to be the top-of-the-line. I assume a plow is made for those models? I'm probably too sentimentally attached to the old 129, and also probably too swayed by all the guys on the other forum telling me that I should keep it going as long as I can. Beginning to think a new cub might be the better way to go. I know that the spindles on my old mower deck sure aren't getting any better. There is a good deal of play in there - especially the larger, center spindle.
 

cpurvis

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We had a 109. When the 10 hp Kohler blew, we replaced it with a 12 hp. I'd love to have it back.

If it was me, I'd keep it and rebuild or replace the engine.
 

bertsmobile1

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  • / Buy a new cub or try and fix up my 129 hydrostatic?
Well we all know the phrase " they don't make them like that any more" and it is true.
My main workhorses come from 1966 to 1969.
With the price of Kohler parts I would go the way of a new engine from one of the surplus engine suppliers
 

three4re

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  • / Buy a new cub or try and fix up my 129 hydrostatic?
We had a 109. When the 10 hp Kohler blew, we replaced it with a 12 hp. I'd love to have it back.

If it was me, I'd keep it and rebuild or replace the engine.

Very little difference, I believe, between the 109 and 129 - possibly just the different kohler engine. The 129 has a 12 hp. Your thoughts echo those of many people on several different forums...that of fixing the old cub rather than replacing it. I'd be really curious to see how it would run with a rebuilt engine!
 

three4re

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  • / Buy a new cub or try and fix up my 129 hydrostatic?
Well we all know the phrase " they don't make them like that any more" and it is true.
My main workhorses come from 1966 to 1969.
With the price of Kohler parts I would go the way of a new engine from one of the surplus engine suppliers


More advice to repair the 129...thanks. I've been leaning in that direction all along, but if I do it I just hope the rest of the tractor and deck will hold up. The leak in the transmission has me concerned even though it's not gotten any worse over the years. And if the deck goes, not sure I can even get another for it - probably could find one on eBay or something like that.
 

Scrubcadet10

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  • / Buy a new cub or try and fix up my 129 hydrostatic?
Fix up your 129. Cubs now are POS.
 
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