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Sunstars_2

AC 720 Onan Engine

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Sunstars_2
I just finsihed repowering a 77 yr old neighbor's 720 with a 24 Hp Honda. I tried to get him to rebuild the Onan CCKB/MS Spec 2733J but he was tired of poor starting, leaks and using oil. I opened the heads and find no step in the bores or scratches. Rings are likely worn. Valves are loose in the guides so it looks like unleaded gas got to it. There seems to be no play in rod or crank bearings so I think this engine just needs an overhaul. With the demand for 720. 620 & powermax tractors, what is this engine worth? It is complete except for the front clutch. I would buy a tractor and overhaul/install it but these tractors seem hard to find. Any suggestons on a fair asking price? Or anyone have a 620, 720, Powermax in the midwest with a broken engine for sale? Thanks

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iweld
Welcome to the club Sunstars. I think your friend was wise in repowering with the Honda. About 15 yrs ago I rebuilt my Onan and if the Honda kit would have been available then I would have done that. Have you researched the cost of rebulding your Onan? I was shocked when I started to buy parts 15 years ago. $65 ea. for pistons, $10 each for head gaskets, $20 each for ring sets, $185 for a cam shaft, $185 for a muffler,$35 & $47 for valves, (although these can be had aftermarket now). I would part out this Onan and save my money for the Honda myself. I think there is a large increase in performance with the Honda too. Look around in the forums here and you will find that the Onan 20 hp is no more then a 16 hp with a different carb and intake. I'll bet the Honda is a lot quieter than the Onan too.

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powermax_paul
Motor as is, probably worth $200-300. If you part it out on Ebay, I'm guessing that you could get $200-300 for the flywheel alone, $50-100 each for timing cover, pan, coil, carb, intake, stator, etc. The electric clutch would also be a high$ item. Good luck.

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slo383
hi, where does one buy the honda kit or engine? thanks sam

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Sunstars_2
I got the kit from Small Engine Warehouse. Not a bad kit, needs a little work to fine tune some pieces. The Honda 24 Hp is a snug fit but does not require any modificaion to the chassis and only trimming about 2" off the hood baffle. The man I did it for drove it home this morning and will put it to work mowing tomorrow.

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Les
I really like the AC 720/Powermax tractors. The problem is that they just cost too much to buy and maintain.

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MN_FISH
Sunstars_2 What did you decide on doing?

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Sunstars_2
Wayne, I have been busy with some other projects so no decision yet. The engine belongs to my neighbor & I was trying to find out if there is some value for the engine or parts for him. Are you looking for a complete engine or parts? Paul's response seems to indicate the parts have some value but my neighbor may be willing to sell the complete engine though shipping would require crating and truck freight.

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