BASIC HINTS FOR REDUCING DISPLAY ENGINE SPEED

By Staff
Published on May 1, 1982

44071 Clinton #A-4, Indio, California 92201

Early-day gas engines idling away at fairs and gas engine
meetings are always an interesting sight. For those engines that
are restored for display purposes where only a light work load or
no work load at all is required, it if often an advantage to have
the engine run slowly. This can often enhance the interest in the
display and also make it easier to observe the mechanical
operations of the engine. Although most early-day gas engines have
some form of speed adjustment, certain minor modifications can be
made to even further reduce the speed of the engine used mainly for
display. This article will cover basic hints and modifications for
hit-and-miss governed engines. These modifications are simple and
do not affect the cosmetic appearance of the engine. Moreover, if
it is ever determined to return the engine to its original working
speed, the elimination of the modifications is equally simple.

Many of the governors on hit-and-miss gas engines have rather
strong return springs on the governor weights to maintain the
engine speed at something near 500 rpm. Replacing these original
factory springs with lighter springs can substantially reduce the
speed of the engine. It is relatively easy to replace these springs
if the governor weights are mounted in an accessible location such
as on a flywheel or on a camshaft gear. If the detent arm has a
strong return spring, it may become necessary to replace this
spring with a lighter spring or, in some instances, eliminate it
completely. A strong spring forcing the detent arm away from the
latched position may preclude slowing the engine even though there
are lighter return springs on the governor weights. Many hardware
stores carry an assortment of inexpensive light springs, making it
possible for the engine restorer to find the right combination of
springs to successfully reduce engine speed. Do-it-yourself spring
winding kits are also available.

Once the engine speed has been reduced, the next step is to
encourage the hit-and-miss engine to coast a little longer between
firing cycles. When these engines were used for work and operating
at their original RPM, the ignition was usually adjusted to fire at
or slightly before top dead center. When the speed of the
hit-and-miss engine has been substantially reduced, the engine will
often run smoother and coast longer if the ignition fires at
slightly past top dead center.

Some engines will have difficulty in drawing fuel up into the
mixer or carburetor at lower speeds. This is usually because of the
original style check valve at the bottom of the fuel line. These
old style valves are often heavy and may even have a return spring
forcing them in the closed position. This type of valve does not
function easily at low speeds. One solution to this difficulty is
to replace the original check valve with an extremely lightweight
modern unit. (One example of a replacement valve is Briggs and
Stratton part #296476, which can be used with ?’ tubing.) These
new valves function better than many of the heavier, older ones at
lower speeds and will still work well if the engine is returned to
its original speed. Some engines also have rather large fuel pipes
leading to the mixer, and it is often advantageous to replace these
with ?’ tubing. This will also aid the mixer in drawing up fuel
at lower speeds.

The suggestions mentioned here are both basic and relatively
simple methods for reducing the speed of display engines.
Undoubtedly, there are other methods to achieve the same end that
other early-day engine advocates favor, and it would be interesting
to hear about them.

PAULINE SCHAEFER

Mrs. Pauline V. Schaefer, of York, Pennsylvania, who died March
9, 1982, traveled thousands of miles to represent Stemgas
Publishing Company and other firms at steam and gas shows in the
Middle Atlantic States.

She and her late husband, Elmer W. Schaefer, celebrated their
50th wedding anniversary in 1977. Elmer, who died in 1978, was well
known for his model engines.

A tiny person, Mrs. Schaefer was durable nevertheless. She spent
long hours on the road and even more at the shows where she
displayed her merchandise, sold books, and took subscriptions,
exchanged news and views with her customers, and generally kept up
with what was happening.

She was a meticulous record keeper, settling up her accounts
within a short time after each show closed. Her truck was a model
of tidiness considering the overflowing cartons she carried, and
her counters were always inviting. Many persons, young and old,
would browse at her stall; that never bothered her in the
slightest. She received aid in transportation, but handled her
business transactions on her own.

We looked on her as a valued member of the ‘Stemgas
Family.’ She represented us ably and made a lot of friends for
us. We miss her.

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