Lawn Mower Engine.

[hurleyjd]

I am replacing a 30 hp briggs engine on my lawn mower with a 27 hp briggs. The original engine had a crankshat that was 3.5 inches in length. The new engine has a shaft that is 4.25 in length. Here is my plan I have cut a piece of tubing that fits very close to the OD of the shaft I plan to use it as the tool or gauge to be used to cut the shaft with a abrasive cutoff wheel any problems here as what I am trying to or shim the electric clutch with spacers . I need to remove at least .75 inches from the end of the shaft. The piece of tubing is the length the shaft needs to be and is there to hopefully guide me in keeping it true.

 

[jltrent]

That sounds like one of those jobs that is a one shot deal....If you can get it chopped off straight and everything else is the same it should work.

 

[Silver]

Would it be possible to just lift the engine and shim it up to the correct height so the crank sits where you need it? Assuming its a vertical shaft...

 

[Caustic Burno]

Would it be possible to just lift the engine and shim it up to the correct height so the crank sits where you need it? Assuming its a vertical shaft...

I was thinking bushing and longer engine mount bolts. That's a heck of a lot easier than cutting the crank.

 

[Atimm693]

That would be fine, but you'll need to make sure the threads in the crankshaft are of sufficient length.

 

[greggy]

I dunno.

But what about some spacers on the engine mounts so shaft is in same position as before.

 

[Nesikep]

any chance you can post pictures of how this mounts?
if you have clearance underneath, you could put the clutch on then have a sleeve over the rest of the shaft so the bolts pinches it in place?

 

[hurleyjd]

That would be fine, but you'll need to make sure the threads in the crankshaft are of sufficient length.

There would be over an inch of threads left in the shaft after cutting the shaft.

 

[hurleyjd]

As far as the spacers go if I only needed about an 1/8 of an inch or so I could be okay with that. Keeping the shaft at the 4.25 length would mean that the spacers would be .75 of an inch thick. Also there would need to be a .75 of an inch of machinist bushing to get the drive pulley in place. The mower deck electric clutch might be all right as there is a thick idler pulley on the deck that keeps the belt in position with the rest of the deck pulleys. Also the longer drive shaft would put more side load on the motor shaft. Thanks for all of the solutions but I think that shortening the shaft may the way I go.

 

[hurleyjd]

Trimmed the shaft to the required dimension. Took about ten minutes or less to trim and dress with a file.

 

[greggy]

Sounds easier than spacers...

Re the shaft, if it was a prob with load, they would not have that length you would think ?