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what to use for a modern repower for the Bolens medium frame tractors

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#1 TravelinJavelin OFFLINE  

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Posted October 21, 2016 - 12:58 PM

curious more than anything what can someone use to replace a blown single cylinder engine with on these without a lot of fab work....... I know there s couplers and other shaft stuff to contend with I see briggs vanguards were used but I guess they don't make the v- twins anymore? so whats available if anything?


Edited by TravelinJavelin, October 21, 2016 - 12:59 PM.

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#2 boyscout862 OFFLINE  

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Posted October 21, 2016 - 01:13 PM

I think that someone on here did a thread on using one of the HF 13.5 hp Chinese engines. I would think that it would only require a spacer to raise the engine pto to the same elevation as the existing pto. If the old and new PTOs are the same diameter, just switch the pulleys. Make sure the key switch is compatible with the type of ignition that the engine has. Good Luck, Rick
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#3 TravelinJavelin OFFLINE  

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Posted October 21, 2016 - 03:16 PM

oh this more for future reference more than anything just in case something takes a bad turn for the worse

#4 EricFromPa ONLINE  



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Posted October 21, 2016 - 04:42 PM

Worst thing to find if doing a Non OEM engine swap would be the driveshaft coupler or adapter plate.Medium frame Bolens driveshaft hooks to the flywheel instead of the crank.So you will need to Modify your existing stub shaft or make an adapter or find some place that sells the stub shaft for the engine you plan on using.


That's going to be a pain in the butt as most engines flywheels are all different.  



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Posted October 22, 2016 - 07:07 PM

I installed a 13 HP Predator (Harbor Freight Honda Clone) on my 1975 MF12G. I would have liked to keep the HH120, but it was cost prohibitive to find a piston and bore the block, much less the valve work and such. Anyway, it runs flawless, consumes about half the gas and is much quieter with less vibration. It wasn't a drop-in swap but at least the bolt holes in the chassis lined up perfectly. I know it doesn't relate to your Bolens but a re-power will have similar problems and advantages from brand to brand I would think.


I'm sure the shaft drives represent a whole lot of different problems as Eric was saying though.


Link to Predator engines



Folks on this forum gave a lot of great advice while I was doing the swap, especially Doug-DH1 who had done a couple of MF Hydro swaps before I did the gear drive swap.



Edited by MFDAC, October 22, 2016 - 08:38 PM.

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