Attaching a lawnmower blade to a crankshaft without using a blade adaptor??

Hi,

About 3 months ago, I went to a local lawnmower center and bought a 3.75hp Briggs flat head for 15 quid. My plan for it was to attach it to an old lawnmower deck I have and mow the lawn. However, The blade adaptor that came with the engine is too tall for the deck so the blade sticks out too far. How could I attach the blade without using the blade adaptor?

get different adapter or raise the engine on spacers.

1997 Murray wrote:

raise the engine on spacers.

Would the engine not vibrate alot?

not any more than it does now. Just put 1" (26 cm) spacers under the mounts with 3/8" hole drilled through the center, get longer bolts, and bolt it down. It should not have a problem with vibration at all.

1997 Murray wrote:

not any more than it does now. Just put 1" (26 cm) spacers under the mounts with 3/8" hole drilled through the center, get longer bolts, and bolt it down. It should not have a problem with vibration at all.

Okay I`ll do that. Thanks!

I don't think you can run without an adapter. If there was a way the corporate bean counters in charge of budget would have done it already, they will remove anything they can to save a dime.

Right so I have a little bit of time now to work on the mower. How would I go about making spacers?

I personally, was never keen on engine spacers. Increases the shear loading on the bolts (by a large margin), and can result in failure. Other failures can include breaking the mounting flange on the engine. I'm not saying it WILL, I'm saying it CAN.

Is anything stopping you from shortening the adaptor???

Doc has a good point. Very valid. On my speed mower i raised the engine with 1x1" boxed pieces with a hole drilled and welded to the engine plate. IMO, acts just the same as a engine plate and mounts should not snap off or anything. Id do it this way, def not stacking washers or that ghetto stuff.

Doc Sprocket wrote:

I personally, was never keen on engine spacers. Increases the shear loading on the bolts (by a large margin), and can result in failure. Other failures can include breaking the mounting flange on the engine. I'm not saying it WILL, I'm saying it CAN.  

Is anything stopping you from shortening the adaptor???

Right okay thanks for the info Doc!

I`ve tried doing that but it doesn`t really work. I`ve tried researching to see if I could buy one and there doesn`t seem to be any different ones.

redlinemotorsportts wrote:

Doc has a good point. Very valid. On my speed mower i raised the engine with 1x1" boxed pieces with a hole drilled and welded to the engine plate. IMO, acts just the same as a engine plate and mounts should not snap off or anything. Id do it this way, def not stacking washers or that ghetto stuff.

Yes but the only problem with that is that the mower deck is Cast Aluminum and you can`t weld anything to it.

Would it be possible to cut the crank shaft to shorten it?

You can. Keep an eye on the thread depth, though.

I second what Doc said that size engine often have two woodruff key slots for different decks years ago I had a guy to cut one for me worked just fine.

So, a waaay long time ago I cut a wee bit off the shaft to shorten it but I then found my blade was really blunt and didn't match up with the adapter. So now I left it in a heap until today I dug it out and found that the exhaust had leaked oil out all over the mower and the floor.
Anywhoo, I checked the oul ebay and found a blade that fits my mower (18") and my blade adapter (Have checked this with the seller)
http://www.ebay.co.uk/itm/330790180681?euid=580c3a66b34c4140a05ec942c9b00284&cp=1&exe=12742&ext=32470&sojTags=exe=exe,ext=ext