flywheel adaptor

[wwbragg]

I am repowering three Simplicities with the Harbor Freight 13 HP engine; a 727, a 3112H and an old Landlord variable drive.  Now Small Engine Warehouse makes some flywheel adaptors but when you mention Predator or Harbor Freight they almost hang up on you.  So I went to the local machine shop and here is what came out.  First, I had them drill out the three 6mm holes in the flywheel that sit under the starter flange. Drilled them to 5/16 and threaded them with SAE threads.  I don't want the flange to spin under the extra load.  Then they welded a 7/8in steel ring from 1/8in flat stock onto the flange.  Next, they welded 3/8in nuts under the steel ring.  The nuts align with the Simplicity drive shaft coupler.  Done.  Can't wait to see how they hold up.

[720nut]

looks good but is it cost effective ?

[wwbragg]

The guy at the mower shop told me it would cost around $1000 to rebuild a Briggs 19 or 23.  The Predator 420 cost $300.  This adaptor was another $110.  I know of no other alternatives so yeah, I think it is a good way to go. 

[wwbragg]

Here it is mounted on the Predator 420, ready to install on my 725.

[GregB]

Air cooled VW parts on the shelf below?

[wwbragg]

5 minutes ago, GregB said:

Air cooled VW parts on the shelf below?

Yeah!   My son towed my 69 bug about 60 miles and it slipped into gear.  Blew a rod through my blue printed 1776 AS21 case.  Was going to build another one for my Kelmark GT but my tractor projects are a better match for my skill level.

[wwbragg]

OOPS!  It doesn't fit.  The 7100 series coupler is too long for the 725.  The grill mounting bracket in the middle of the axel is in the way.  I'll have to use the fiberglass disk common to most other models.  Maybe I will sandwich a 67 Mustang steering coupler between two fiber disks for a little added strength.  The bolt pattern is the same.  In the picture you can also see the raised mounting plate needed to raise the new motor.

Edited July 16, 2017 by wwbragg

[wwbragg]

I ended up using the original 725 coupling assembly (Simplicity part number 2154194) that I found on ebay.  A previous owner replaced the coupler with a piece cut out of a car tire - - - go figure.  That gave the clearance I needed and after removing excess wiring, she fired right up.  But now I must have a custom exhaust made (think chrome stack) and modify the air cleaner cover so the hood and grill will fit.  I don't want to hack up the original sheet metal - - - unless somebody has one that has already been partially mutilated and wants to donate it to the cause.  

Edited August 10, 2017 by wwbragg