Early in 1928, the Hercules Products Division of Servel, Inc.
began producing the X model line of engines. The 1
–3/4 HP, 2- HP and 3- HP sizes were new
designs. The 6 HP and 8 HP sizes were the same as their older
models, with the exception of three-hole, disc type flywheels
rather than the traditional spoke type.
A 1- HP and a 6 HP are shown here, and as you can see one of
their most outstanding features was the three-hole flywheel. Almost
all of the engines built were the XK Model (kerosene), with only a
few of the XI (gasoline only) Model engines being produced.
Total production of the X model line came to 17,500 engines. I
currently have 214 X model engines on my list that I have seen or
that have been reported to me. The lowest known serial number at
this writing is 1,317, and the highest is 18,357. The three smaller
sizes were produced and sold for only two years. The Sears catalogs
show them beginning in the fall of 1928 and ending in the spring of
1930.
Many of X model engines have casting dates on one or more of
their parts, and the table below (Table One) shows engines where
the casting dates were recorded.
Seventy-five percent of X model engine production were the
Economy brand, the remaining 25 percent being the Hercules brand.
It is interesting to note that after serial number 17,000 most of
the production was in the 6 HP and 8 HP sizes. That is because
production of these two sizes continued into 1933, and these were
sold by Sears along with the J models, which were introduced in
1930. Production of the smaller size X model engines was
discontinued in 1930.
TABLE ONE:
Comparison of Casting Dates, Serial Numbers and
Brand
Serial Number
Casting Date
HP
Model
Brand
1,461
4-21-28
2-
XK
Economy
1,540
5-14-28
1-
XK
Economy
7,128
1-1-29
6
XK
Hercules
7,298
1-14-29 (head)
1-
XK
Economy
1-31-29 (block)
8,024
2-27-29
1-
XK
Hercules
8,669
1-26-29
3-
XK
Hercules
9,032
4-11-29
6
XK
Unknown
9,897
3-28-29
1-
XK
Economy
12,063
7-6-29
3-
XK
Economy
13,069
8-15-29
1-
XK
Hercules
13,970
4-25-29
1-
XK
Economy
14,544
9-11-29
1-
XK
Economy
15,557
9-20-29
1-
XK
Economy
15,889
10-22-29
1-
XK
Economy
17,740
3-25-30
8
XK
Economy
TABLE TWO:
X Model Production Breakdown by Size
HP
Number Known
Percentage
Estimated Production
1-
110
51
8,925
2-
24
11
1,925
3*
2
1
175
3-
21
10
1,750
4*
6
3
525
6
39
18
3,150
8
12
6
1,050
Total:
214
100
17,500
These 3 HP and 4 HP sizes were simply re-rated 2- HP and 3- HP
sizes. They are seldom seen and came out very near the end of
production.
An unrestored 1- HP Hercules Model XK, serial number unknown.
These engines were produced from 1928 to 1929.
The second table represents a breakdown of sizes and production
of X model engines, as near as I know. While all these numbers
might seem confusing, and perhaps even boring, these bits of
history are important to have generally available – they don’t
do the gas engine hobby any good if they’re just written down
in a book in my house. Any additional information on X model
engines or casting dates is welcomed and will be added to the
list.
Glenn Karen is a noted authority on Hercules engines.
Contact him at: 20601 Old State Rd., Haubstadt, IN 47639, or e-mail
at: glenn.karch@gte.net
