OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott bonnar 45 frame types

Folks,



In my search for another scotty 45, I have noticed that some have a single solid frame member whilst the later ones have twin rails. Does anyone know what year this change occured?

Which of the two are the preferred design?

BM

Hi BlackMilk, Unfortunately, there is no clear date for the change from the solid engine deck to the twin rail, but I can tell you that in the Selected Product Range in 1974 - 1975 the Models 450407 14"; 450423 17" and the 450431 20" all had the solid engine deck fitted.

The 14" had a 2.25HP Briggs and the 17" and 20" had the Kirby Tecumseh/Lauson engine HK30 3HP engines fitted. However, some 17" machines may have had the HK25 2.5HP engine fitted.

By 1978, Scott Bonnar had changed to the Briggs and Stratton engine for the entire range and also all Models of the 45 were by now fitted with the twin rail deck.....
See the brochure; Click HERE

There have been cases of fatigue cracking of one or both of the twin rails....but these are easily repaired. Choice is up to the individual....the solid deck may be better, but there are output shaft size differences between the Kirby and the Briggs.....so extra expense there fitting the later Briggs to the early chassis.

Hi Deejay,
I'm new to the site but picking up lots of usrfull info so I am liking it very much.
I have just picked up a Scotty 45. It is a 14" twin rail with a HK30. In response to your post above does that mean my scotty is not an original or would it be a unit that they had left over and threw the 3HP Kirby/Lauson at just to move stock??

Regards,
2IC

Mate,

That old Brochure is gold! Noice

My gut says look for one with the solid deck as I am contemplating on using it as a dedicated groomer, so the stronger the better.

Thinking of using a Honda gx to power it but need to do my homework first to ensure matching shaft sizes and heights from the mower deck.


BM

Hi 2IC, and a warm welcome to the forum.
It's always great to welcome another Scott Bonnar owner on board.

Your machine has the older style SB decals but is the later style twin-rail engine deck. I would surmise that yours is a 'transitional' machine (and a genuine Scotty Model 45) that was assembled around 1976-77 prior to the introduction of the later model (orange painted) Briggs and Stratton engines.
Your machine is unusual for a 14" machine having the 3HP engine fitted....maybe this was a special order for a customer who for whatever reason needed the extra horsepower.....maybe a steep sloping terraced lawn.
I wish we had more records from SB to find out the reason.
It is a very nice machine. on a good score!

Once again 2IC, to OutdoorKing.

I have noticed in some pictures of old scotty's the rear roller appears to be in three pieces. My 17" inch cylinder has two pieces - does that mean the three piece rollers are 20" machines???

BM

Hi BM, you are quite correct....it is the 20" Model 45 Scotty. The third segment is roughly 3" wide....the other 2 are the same as the 17" machine.

Thanks Deejay,

I presume that the majority of parts are interchangeable with the 17" and are still readily available??

BM

Hi BM, no, not in the literal sense....if you mean the nuts and bolts; yes....but the 20" machine has an 8 blade cylinder reel versus 6 blade for the 17", a 20" soleplate and bed-knife blade; 3 segment rear roller versus 2 for the 17", a 20" chassis, longer clutch engine shaft, a 20" front roller and roller frame, a 20" catcher and a larger engine on the early machines.
At present, most common parts are still available, after market.

Just picked this Scott Bonnar reel mower.

Anybody know what model ( year )

Looks like a bitsa.

Its got a clutch off a victa imperial or morrison or perhaps a rover thoroughbred.

Pretty sure SB didn't use villiers past the 50's so the motor wouldn't be original

My bet is a seriously changed model 33 scott bonnar, but wait for any proper experts on these to answer