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Engine Upgrade?

2520 Views 6 Replies 4 Participants Last post by  hoot
I have a silver craftsman 10hp 30 in cut that the engine threw a rod through the side of the block and the previous owner gave to me. The mower is in like new condition and include a bagger system. My son wants me to put one of the 18hp twin B&S that are setting in the garage on it. The engine will just fit in the rear housing, but I will have to fabricate a custom exhaust around the the bagger. I am considering the idea but am a little leary about the speed and power associated with the 8 additional hp. What does everyone think? Are we crazy or not?
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The engine size is not going to have anything to with speed as both engines are controlled by governors although you could change it into a drag racer if you chose. I would not put that size engine on it myself strictly because there is not point in having that much horse power. I would be selling the big engine and using a smaller, cheaper engine but then since you have the engine, no problem using it. I am a trader/rebuilder, I assume you are not.

You do not say WHICH 18 hp twin you have. IF it is an opposed twin, the mounting holes will not match, you will need to measure and re-drill. Crankshaft will be the same.

Walt Conner
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Thanks Walt, I work on mowers in my spare time and do trade things on occasion. I have three of the 18 hp opposed twins in various stage of assembly in the garage from tractors that we scrapped for one reason or another. My son just thinks it would make a unique mower and likes to challange me to do strange things occasionaly. The redrilling of the mounting holes is no problem as is the making of a custom exhaust.
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I've got a Craftsman/Murray 502 mower with the 10HP Tecumseh engine. I can pull the front wheels off the ground with the original motor. 18HP would be scary. Better plan on adding some weight to the front.
Don't know what the hood looks like on the craftsman, but you may need to add slots or louvers for cooling
I'm assuming the mower looks like this:

If you do, it may be worth while to put some kind of back stop/scatter shield between the engine and the seat.
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Well I came across a 8 hp Briggs for $50 (with new carb) last week and and decided to put that in inplace of the 18 Hp. The motor and mower work great and I anly have the cost of the motor in it. Now I an going to try to sell the mower and make some money for my next project.


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