20601 Old State Rood Haubstadt, Indiana 47639
Once the cam gear and exhaust valve adjustments have been
properly set, the third step, timing the ignition, can he made.
Although there are several different ignition systems used on
Hercules built engines, in this article the Webster system using
the M, K and L magnetos will be discussed. The instructions given
here are for engines to be run at or near rated speeds and that are
intended to pull a load. It should be noted that if parts are badly
worn or other repairs poorly made, the necessary adjustments may be
hard to make and maintain. Further, these adjustment instructions
can be used on other brands of engines once a timing reference
point has been determined.
Some engine instruction manuals give the timing recommendations
in terms of degree of spark advance ahead of inner dead center.
Jumbo literature mentions eight degrees of advance for each 100
RPM; i.e. 40 degrees for 500 RPM and 28 degrees for 350 RPM.
Racine-Sattley literature lists 35 degrees for the 1 HP graduated
down to 15 degrees for the 15 HP. These recommended advances appear
to be greater than those obtained when properly setting the advance
for Hercules built engines. The degree of timing advance depends on
a number of factors, including RPM, stroke length, flywheel weight
and flywheel diameter.
In the next article the discussion will cover timing and other
adjustments for slow running show engines.
