G'day all
... and thanks Tyler for starting a new topic.
AVB's comments on 100:1 mixes in modern engines is not surprising.
My best view is that this can is not a Victa factory can.
I say that because Victa's association with BP simplified matters.
Victa BP Zoom (25:1) and BP Outboard Zoom (50:1) simplied things.
Most Victas ran 25:1, but Victa primary documents show 50:1 was
recommended for the Victa Lightweight, Twin, Supreme and Imperial models.
I have not found a reference to an 80:1 mix for Imperials in any Victa
document. [
See post below: I'm an idiot].
My best assumption is that lower compression (head spacer on the imperial) means less temperature, maybe meaning the cooling fins can take care of the cooling aspect more by themselves, leaving the oil more solely for lubrication.
Yes Tyler, I feel that is very much the case ...
I think, as a general rule, a lower compression ratio means a cooler running engine.
I guess a leaner fuel mix was required to prevent carbon deposits in 2-strokes.
Here's the problem though ...
The First Victa catalogue covering the Imperial 2-strokes was the
1973 one (The 2-stroke Imperial was introduced in late 1972 for the
1973 range).
That Booklet said this about the Imperial engine:
Amazing new 2-stroke engine
Up till now most reel mowers have
been powered by 4-stroke engines.
But this year Victa is changing all
that with the introduction of a
great new low-compression 125 c.c.
2-stroke engine. This engine is
designed to run smoother and last
longer. It also runs cooler and
needs less oil. (In fact Victa recom-
mends BP Outboard Zoom for this
engine: a mixture with less oil).The devil is in the detail.
That the engine ran cooler because of lower compression
was a
byproduct of the
real reason - to make the engine
smoother.
Why? Well, because of the small centrifugal clutch combined
with strong 2-cycle power impulses from a mid-range rpm 2-stroke.
It really was a compromise design.
It is generally accepted that reel lawnmowers require less hp than their
equivalent rotary designs. This is because of the scissor action, and the limitations
of what can be cut (about three-quarters of the reel diameter as a general rule).
Tyler, you point this out: reels do not suffer from
spike-loading that rotaries
certainly do suffer.
Reels mowers can't really turn grass into lawn.
They can turn lawn into better lawn.
Cheers
-----------------------
Jackp.s. a very rewarding topic.
Many thanks to all contributing members here.
