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Swapping rototiller engine with push mower engine


OhioSteve's Avatar
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05-26-15, 03:32 PM   #1  
Swapping rototiller engine with push mower engine

Anyone ever done it? The original engine, B & S is on its last leg, only 4 hp. Is it possible to swap it with say another 4 hp engine off of a lawnmower? I already noticed one problem. The mounting holes are 4 on the current tiller engine, where as most push mower engines are 3 hole designs. Do they basically all run the same RPM? Don't want to over do RPM's to the tiller part. Shaft length is another thing I'm not sure of. I should be ok with the shaft diameter, I think. Just need to take the pulley off the old engine.
Any thoughts? Thanks

 
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Pilot Dane's Avatar
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05-26-15, 05:05 PM   #2  
Without knowing the details of the engine your removing and of the new engine it's all just guessing but it seems you see some of the pitfalls; mounting bolt pattern, shaft length, shaft diameter, rotation direction... But anything is possible. How hard or easy it will be depends on how well you do your research and pick the right replacement engine. Then you need to consider all the work and possible risk of swapping engines versus reparing/overhauling your current engine. Almost anything can be fixed.

 
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05-26-15, 05:29 PM   #3  
Most mower engines rely on blade for flywheel effect while the non mower engine applications need a heavier flywheel to maintain correct engine operation.
Try running mower engine without blade and observe difference.

RR

 
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05-26-15, 06:05 PM   #4  
My walk behind mowers are all vertical shafts while my roto-tiller, chipper and snow-blower are all horizontal shafts . . . . so I would think that if you have a match on the orientation, you may already be past 1st base !

 
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05-26-15, 06:14 PM   #5  
All the points of consideration have been brought up. As mentioned by Rooster: You will need to be able to swap the flywheel from one to the other so you can have the cast iron flywheel instead of the aluminum one used on the push mower. Don't try to crank the one with the aluminum flywheel or you may hurt yourself (unless it still has the blade on it). If the flywheels aren't the same, it's not going to work.


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OhioSteve's Avatar
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05-27-15, 05:14 AM   #6  
Good point about the flywheel, as I know what it's like pulling the cord with "no load" on it.. Easy to rip a rotator cuff.
So the thinking is, swapping flywheels as well? Guess I never realized that different metals were used in flywheels. I assume the magneto/flywheel would have to stay together as well. Which could also mean a spark plug change.
This maybe a bit more than I want to undertake. It would be easier to just find a compatible engine, if the B & S I currently have wasn't so old. Only bright spot is the current engine is a horizontal shaft, (as are most push mower engines.)
-Thanks all for the advice.

 
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05-27-15, 05:36 AM   #7  
Only bright spot is the current engine is a horizontal shaft, (as are most push mower engines.)
huh???????????????????????????????????????????

 
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05-27-15, 05:51 AM   #8  
Lol, sorry. Vertical.....

 
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