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A “Complete” List of Lauson Small Engine Models


by Craig DeShong 03-22-2010 Views: 17,022

EDITOR NOTE: The function codes that make tables are temporarily unavailable, August 27, 2019. -- Harry

This article catalogues a “complete” list of Lauson small engine models. Categorizing them can be somewhat challenging, since Lauson was building flywheel (Hit and Miss) engines at the same time during their early small engine production period, and they also built throttle controlled, hopper cooled engines that I categorize more as flywheel engines rather than small engines; so it can be challenging to count them, and there can be disagreement. Still, here is my best attempt. I’ve arranged them (more or less) in chronological order with respect to the year first introduced. I’ll warn you that some of these dates are my “best guess”. I’m open to corrections if anyone wants to dispute anything I’ve listed here.

I’ve also categorized the list with respect to design, placing the early overhead-valve engines first.
The (what I call) 1st generation style of block engines follow next. All these engines have the same basic block design and are among the first group of “small engines” Lauson produced.
The (what I call) 2nd generation style of block engines follow. All these engines fall into the block design that most collectors identify as the “classic” Lauson design.
The (what I call) 3rd generation style of block engines bring up the end of the list. These are the two aluminum block engines Lauson introduced just before they were bought by Tecumseh.

Overhead valve engines
[table=”head”] Model|HP|Introduction Date|Withdrawn Date|Comments
VA|2|1929|1935|Overhead valve air-cooled (1st Lauson “small engine” built)
VR|2|1929|1935|VA but Water-cooled with radiator
VW|2|1929|1935|VA but water-cooled with water tank, sold under “Alpha DeLaval” label
UA|3|1933|1945|Overhead valve, upgraded model of VA
UR|3|1933|1935|Overhead valve, upgraded model of VR
UW|3|1933|1940|Overhead valve, upgraded model of VW
UAS|4¼|1933|1940|Overhead valve, replaced VA and UA
UWR|4|1933|1940|Minor version change from UW?
ZW|5½|1935|1937|Like UW but larger?

1st generation design engines, all L-Head design
[table=”head”] Model|HP|Introduction Date|Withdrawn Date|Comments
RA|½|1930|1933|Air cooled
RAB|½|1930|1933|Same as RA but battery ignition
RAU|¾|1930|1933|Larger version of RA suction carb. standard, optional float carb.
RAY|1|1930|1941|Larger version of RAU float carb. standard
LA|1½|1930|1935|Larger version of RAY
LWR|1½|1933|1945|Based on LA but water-cooled with radiator
LW|1½|1933|1935|Marine version of LWR, water-cooled
LB|2|1935|1945|Replaced LA, air-cooled
LBM|2|1940|1945|Marine version of LB, no governor, air-cooled
LF|2¼|1935|?|Replaced LW, marine engine water-cooled
LFR|2¼|1935|1945|LF with radiator

2nd generation design engines, all L-Head design
[table=”head”] Model|HP|Introduction Date|Withdrawn Date|Comments
RLA|¾|1935|1945|Air cooled, built for the military?
RLB|¾|1935|1937|Like RLA, built for washing machine use
RLC|¾|1937|1951|Civilian version of RLA? float or suction carb.
RLE|¾|1937|?|Looks like RLA?
RLM|¾|1940|1945|Marine version of RLC, no governor, air-cooled
RSC|1½|1937|1951|Larger version of RLC, suction or float carb., air-cooled
RSM|1½|1940|1951|Marine version of RSC no governor, air-cooled
RC|1½|1940|1951|Water cooled version of RSC
RCM|1½|1940|1945|Marine version of RC, no governor
TLC|2¼|1937|1951|Larger version of RSC, air-cooled
TLM|2¼|1940|1945|Marine version of TLC, air-cooled
H-2|4¼|1945|1957|Oil test engine
PAC|4 ¼|1946|1951|Larger version of TLC, air-cooled
PPM|5½|1948|1951|Marine inboard water-cooled
LMC|¾|1948|1951|Replaces RLC ?, air-cooled
LMH|1|1951|1958|Upgrades LMC
LMV|1|1951|1958|Vertical shaft version of LMH
RSH|2|1951|1960+|Upgrade to RSC
RSV|2|1951|1958|Vertical shaft version of RSH
V|2|1956|1958|Vertical shaft RSH, flush mount
R|2|1956|1958|Vertical shaft RSH with addtl. horizontal PTO
55S|1½|1951|1958|Economy version of RSH? suction carburetor
55A|2|1951|1958|Economy version of RSH? float carburetor
55AB|2|1951|1958|Economy version of RSH? float carburetor
TLH|3|1951|1960+|Upgrade to TLC
TLV|3|1956|1958|Vertical shaft version of TLH
PAH|5½|1951|1958|Upgrade to PAC
PAX|5½|1956|1958|Like PAH, external magneto
(P25 – P44)|6¼|1956|1960+|Upgrade to PAX

3rd generation design engines, all L-Head design
[table=”head”] Model|HP|Introduction Date|Withdrawn Date|Comments
SLV|2|1954|1958|Alloy block vertical shaft
VA|2½|1956|1958|SLV with a larger bore