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Collection, Preservation and Display of Old Lawn Mowers

JP Dating Information

JP SERIAL NUMBERS AND DATES 

JP was unusual in maintaining a relatively simple and consistent numbering system, although it did change a few times between 1921 and 1971.  

  

WHERE TO FIND THE SERIAL NUMBER 

Hand mowers: serial numbers are usually found on the side frame near to the front roller or cutting cylinder. Later motor mowers have a brass plate. Mowers with a removable cutter unit have the number repeated on the side frame. 

  

DECIPHERING THE SERIAL NUMBER 

Use the information below with the coding tables to interpret the serial number. 

Hand Mowers 

1921-1926 

Mowers had numbers only so no accurate dating is possible. During this period the only models in production were the 12" and 16" JP Super; the 16” was prefixed by X. 

1926-1952 

The format generally follows the pattern: 

Mower Model Code - Year Letter - Month Letter - Number (Nth mower of that design made that month) 

1953-1971 

Similar to above but with the Year Letter preceded by a "2" - Month Letter – Model Code – Number (Nth mower of that design made that month) 

 

Motor Mowers 

The numbering system generally follows a similar pattern to the hand mowers. However, as far as we know (because relatively few motor mowers were produced), letters designating the month of production were not used except between 1927 and 1935. 

The format generally follows the pattern: 

Mower Model Code - Year Letter - Number (the Nth mower of that design made that year) 

Where a 4-stroke engine was fitted to a model which also had a 2-stroke version, the number is preceded by 4/ 

From 1955, for models with a single code but produced in different widths, the various sizes were designated by the model code followed by the cutting width (eg B15, B17, B20 etc) and from 1967 the Year Code became E and then ran on but omitting I. 

From 1962, with the introduction of the Super Power Mower Mk5, the serial number was preceded by 5/ 

 

JP MODEL CODES
Model Code
12" Super No code
14" Super F
16" Super X
12/14/16" Super Electric E
15/17/20 Super Power Mower Mk4 B
16" Super Power Mower 22
24" Super Power Mower 21
24" Super Power Mower Mk5 B
14" Super Simplex PV
16" Super Simplex PX
12" Maxees G
14" Maxees FG
9" Minor M
11" Minor XM
12" Major JR
10" Minimower TH
12" Minimower H
12" Monarch H
14" Monarch FH
10" Matchless W
12" Matchless XW
K-Type Power Mower KP
K-Type Electric Mower KE
Simplees D
Sunbeam D
16" Sports Green Mower SG
16" Bowling Green/Golf Green AX
12/14" Maxees Power Assisted PA
12" Maxees Electric G
14" Maxees Electric FG
12" Monarch Electric H
14" Monarch Electric FH

 

JP YEAR CODES
Year Code
1927 A
1928 B
1929 C
1930 D
1931 E
1932 F
1933 G
1934 H
1935 I
1936 J
1937 K
1938 L
1939 M
1940 N
1941 O
1942 P
1943 Q
1944 R
1945 S
1946 T
1947 U
1948 V
1949 W
1950 X
1951 Y
1952 Z
1953 2A
1954 2B
1955 2C
1956 2D
1957 2E
1958 2F
1959 2G
1960 2H
1961 2I
1962 2J
1963 2K
1964 2L
1965 2M
1966 2N
1967 2O
1968 2P
1969 2Q
1970 2R
1971 2S
1972 2T

 

JP MONTH CODES
Month Code
January A
February B
March C
April D
May E
June F
July G
August H
September I
October J
November K
December L

 

MOTOR MOWER YEAR CODES (1967 ONWARDS)
Year Code
1967 E
1968 F
1969 G
1970 H
1971 J