OutdoorKing Repair Forum Forums The History Forum Model Histories SCOTT BONNAR Models MODEL 43 - 20" POWER REEL MOWER

PART TWO - Specification
The Model 43 is a strange mix of previous Scott Bonnar reel mower designs.

The engine was a 2-stroke of Scott Bonnar's own make - the 155cc Model 202 engine.
That's odd - given that the smaller 14" and 16" models offered 4-strokes!


Source: Grant Simpson Collection.
Note: the Villiers Magistar Ignition Unit ... meaning this machine is c1963 or later.

The transmission is as odd as it gets. The primary chain drove an Idler Sprocket.
From here, there was distribution of power via a gear-sprocket arrangement.
The reel was driven via chain; the landroll via a gear train ... in a Model 17
(Supercut) fashion. This would have been an expensive design folly for a
residential lawnmower.


SOURCE: eBay, 2017

The technical defect must remain with the clutching system. There was one primary clutch
controlling the reel and landroll. This is extraordinary! Both the smaller sizes (in the
domestic range) had a primary and secondary clutch by this time. The 43's single plate
clutch was not a step to the left, nor a jump to the right. It was a step backwards for
such a wide cut machine.

One large plate clutch controlled both the reel and landroll. This would have made
maneuvering quite difficult. This was a lawnmower for the open spaces - the large and
'easy' residential lawns that are not so common.

The rollers were aluminium. Scott Bonnar had used this alloy on some electric models,
and on bowling and golf green machines. The post-WWII idea was that good lawnmower
design should not make the reel lawnmower act in dual roles - lawnmower and turf roller.
The primary purpose of the roller was to produce lawn stripes (an aesthetic reason),
rather than unnecessarily compact the turf.


SOURCE: eBay, 2017

TO BE CONTINUED ...