A Study of Palmer Marine Engines Using Old Catalogs

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This old ad was taken from Gasoline Engines Volume 3, a collection of vintage advertising compiled by Alan C. King.

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R.R. 2, Box 697, St. Michaels, Maryland 21663

I became interested in Palmer engines while restoring several for the Chesapeake Bay Maritime Museum in St. Michaels, Maryland. The museum has some old Palmer catalogs which I examined. Then Richard A. Day, Jr. loaned me his collection of original Palmer catalogs. He also furnished me a list of Palmer models written in the 1950's by David Stevens, a Palmer employee. It includes the years the models were built, based on limited company records and the memory of old-time company employees. Stevens' list is incomplete and some of the dates are in error.

Palmer History: In the April 10, 1924 issue of Motor Boating is a brief account of the beginnings of the Palmer Bros. Engines, Inc., written by E.E. Palmer, son of Ray Palmer. Ray and Frank Palmer built telephone equipment in Mianus, Connecticut beginning in 1887. Their company was The Mianus Electric Company. Around 1890, they began looking for a small internal combustion engine to power a pleasure boat on the Mianus River. In 1894 they still had not found a small engine, so they decided to build one. This engine had a bore and stroke of 3?x3? was two-cycle, with make and break ignition. Their greatest problem was the design of the make and break 'sparker,' as existing designs were of long 'on' time and slow release. In later years they claimed to have spent $5000 on development which was a lot of money in those times. However, with their experience in electricity, they solved the problem very well.

The Science Museum in London has cut-away engines on display that are to show the first two-port and three-port engines and they mention the inventors of each. According to the museum, Joseph Day of Bath, England obtained patent 6410 on the two-port system, dated April 14, 1891. I have obtained a copy of that patent, and it does show the familiar two-port system. Day built marine engines and the Science Museum has a 1913 model on display. He used hot-tube ignition on his early engines, though that is not part of the patent. Ignition timing was not well controlled and his engines had a tendency to reverse unexpectedly. The three-port invention, according to the museum, was by Frederic William Cock, also of Bath, and a Day employee. The patent is 18,513, October 15, 1892. That patent clearly shows the three-port system. (These patents are of the period when British patent numbers started with 1 each year.)

Day and Cock obtained U.S. patents in 1895. Day's two-port patent is 543,614, dated July 30, 1895, and the application date is May 21, 1892. Day's residence was Spring Gardens, Bath. He stated that he had patents in Britain, numbers 6,410 and 9,247 (the latter dated June 1, 1891). There is a version in the U.S. patent office that is from 9,247.

Cock's U.S. patent is 544,210, dated August 6, 1895 with an application date March 10, 1894. He stated his British patent is 18,513 of 1892. The patent was assigned to Joseph Day.

American manufacturers, including Palmer Brothers, apparently did not obtain rights to the Day two-port patent. In an effort to recover some royalties, Day sold licenses on the three-port patent to Palmer Bros, and ten other U.S. manufacturers. Day announced this in a notice placed in Rudder Magazine in 1905. Under U.S. patent law of the time, the U.S. patent would expire when the British patent expired. This meant that U.S. manufacturers had to pay royalties only until October 15, 1906. My thanks to Hugh Torrens of the University of Keele, Staffordshire, England for some of these facts.

Now back to Palmer beginnings: By 1896, Palmer Brothers were building two-port engines in several cylinder sizes. They also built boats as the best way to sell engines. Early catalogs had 'Gasoline Engines and Launches' on the cover. Later, there were separate catalogs for launches. I do not know just when Palmer stopped building launches but it was between 1916 and 1924.

That first Palmer engine ran in a launch for 15 years before it was retired. Later, it was displayed in boat shows labeled 'Where It All Began.' It still exists and is owned by Richard A. Day, Jr.

Model List: The tabulation is my list of models based on the old catalogs.. I omitted all engines that were stationary versions of marine engines and all models that were marine conversions of engines built by Ford, Hercules, Wisconsin, etc., though I mention the conversions in the text below. In the right hand column of the list are Stevens' dates plus my approximate dates based on the catalog study. I must stress the word 'approximate,' as I did not have a catalog for every year. Palmer built engines to special order even after they were no longer listed. Furthermore, there are conflicts between catalog dates and Palmer advertisements. More research is needed on introduction and termination dates for Palmer models.

Until about 1960, the last two digits of a Palmer serial number indicate the year an engine was completed for shipment. After 1960, the last digit was the year. I have seen casting dates on cylinders and heads that were later than the nameplate date, but these simply indicate replacement parts. Nameplate dates that help to refine the introduction and termination years are needed. Send them to me at R.R.2, Box 697, St. Michaels, Maryland 21663 or Richard A. Day, Jr., R.R.2, Box 44, Leonardtown, Maryland 20650.

The Catalogs: The following are my notes from the catalogs. I tried to describe the essentials of the designs and note the differences from each previous catalog. Data in the form 4x5 are the bore and stroke in inches.

Before 1900: Palmer Bros., Mian us, Ct.

The cylinder sizes are not listed, but they offered three engines-1?, 3, and 4 HP. The cylinder and crankcase are one casting with the main bearings in the separate end covers. The engine mounting is a pad under the crankcase, like steam engines and stationary internal combustion engines. Make and break ignition is used with the stationary electrode through the removable head and the moving one through the cylinder. The passage between the crankcase and the intake port is a separate part, with a throttle in the passage. Three launches are offered. There are testimonial letters dated 1898 and 1899.

The reader is invited to write for a special catalog of telephone equipment, so their original business has not been abandoned

1902(?): The Palmer Bros, factory is now in Cos Cob, ConnectionChanges-The engines have been redesigned with a horizontal split line through the main bearings, a cast-in mixture passage from the crankcase to the intake port, and side-arms for mounting. They are now called models B, C, D, and E of  1?, 3, 5, and 7 HP. Bore and stroke are not listed. The advantage of the new split line is that the engine could be disassembled without removing the flywheel.

Additions-More launches are offered. Four cycle horizontal stationary engines are shown. Most likely Palmer did not make these engines, but were only sales agents.


Deleted-The horizontal stationary engines.

Additions-Large four cycle marine engines are offered; the F, G, F4, G5, and K. All are twin cylinder except the F4 and G5 which are four cylinder; this is not an error as the G5 really was a four cylinder. No cylinder sizes are listed; however, the F is rated at 8 HP, the G at 12, and the K at 16, so that is the progression of cylinder sizes. One picture applied to all three, so they must have been similar in design. See 1907 for a description of the K.

1907: The cylinder sizes of the B, C, D, and E are now listed: 3? x 3?, 4? x 4? 5 x 5, 6 x 6.

Deleted-The F, F4, G, G5.

Additions-Three-port engines, the O, P, and Q were introduced in the spring of 1906, it states. These are jump spark engines of three different cylinder sizes and are built in one and two cylinder versions. Bore and stroke are not stated. With make and break, they are the S, T, and U. These have the 1907 detachable sparker. Also new-the L (4? x 4?) and the M (5 x 6) are shown as 1,2, and 4 cylinder four cycle engines. They have suction operated (atmospheric) intake valves, jump spark ignition, exposed cams and timing gears, and drip oilers as though there is no lubrication from a sump. A float-type carburetor is used.

Changes-The K is described as a two-cylinder, four cycle L-head engine, 7?xl0. The detachable sparker is now used. There is provision to shift the camshaft to aid starting; we know that this device will be used by Palmer on many future designs.

1908(?): They claim 35,000 satisfied users and now can assemble engines in batches of 100 of one size. Among the supplies is listed dark green enamel. This color must have been used at least through 1908. The pages showing the K engine are missing.Additions-The R (5 x 6) is shown for the first time. The cylinder size indicates that the design is based on the M, which continues in the Palmer catalog. The R is offered in 1, 2, and 4 cylinder models. They have make and break ignition and a T-head with camshafts on both sides. The cams and gears exposed, like the L and M.Changes-The K has been redesigned with a T-head, similar to the R just described. It has exposed cams and gears and make and break with the detachable sparker. This is a major redesign of the K without assigning a new model designation. The L2 and M2 are now available with jump spark.

1910(?): This year there is a gasoline engine catalog and a separate launch catalog, also in the collection. The cover designs are matching. The engine catalog has four pages missing; they probably show the large four cycle engines'. No changes to the model line-up can be seen, though the B, C, D, and E have a new-style water pump. There are excellent photos of the three-port engines. One can examine the multiple drip oilers with a single reservoir on the two cylinder, three-port models.


Deleted-The B and E two-port engines.

Additions-A three-cylinder R (R3). Also added, Q3, P3, and O3 designs.Changes-The L2 and L4 now have a belt-driven mechanical oiler. Enamel is offered in either green or grey, so the change to grey must have been between 1908 and 1912. The two-cycle engines have no drip oilers, so oil is now to be mixed with the fuel. (The Palmer Gas Engine Hand Book, 1911 edition, has instructions for mixing oil with the fuel, 1 pint to 5 gallons of gasoline.) The K series is available with either make and break or jump spark. There is a new 1912 Eccentric Timer which has a very large roller.

1915: This is a gasoline engine catalog. Launches may be in a separate catalog.Deleted-The O3.

Additions-The model E is back.Changes-The R becomes NR (New R) with cams and gears enclosed. The L series has been redesigned as the NL (New L) with T-head. There are the NL1, NL2, NL3, and NL4. The NL has enclosed cams and gears. The NR and NL were announced in a Palmer advertisement in December, 1921, so they must be in the 1913 catalog. The K has been redesigned with enclosed cams and gears, becoming the NK2, NK3, and NK4. These also may be in the 1913 or 1914 catalog. High tension geared magnetos are offered.

1916:Deleted-The remaining three-cylinder three-port engines.

Additions-Palmer offers a kerosene adaptor for two cycle engines. It is screwed into a tapped hole in the transfer port so that fuel impinges onto the hot piston baffle. The engine is started on gasoline, then the gasoline is shut off and the kerosene adaptor turned on. Oil cannot be mixed with the fuel (drip oilers must be used). Not mentioned is a 'hot head' that Palmer offered for two-port engines. It had no cooling passage so is helped to vaporize kerosene. For using kerosene in four cycle engines they offer a dual-bowl Kingston carburetor. New Engine: The TM, a four cylinder L-head engine, 2?x3?. It looks like a small model T Ford engine. Dick Day tells me it was not a Palmer design, but was purchased. It was not a reliable engine.


Deleted: The S1 and S2. There is no mention of kerosene adaptors.Additions: The Q3 is back. The NLS design is added; this is the NL with stroke increased to 6'. There is now an F1

Changes: The NK and F engines are all jump spark..


Deleted: The NLS engines, the O1, O2, and the O3. The TM is not shown, yet it was in a Palmer advertisement in December, 1921.

Additions-F6 and NK6 engines are now offered. The RA1 and RA2 (4?x6) and the RW1 (5? x 6?) variations of the NR.


Deleted-The Q2 The two-port E has been removed again.

Additions-The VH which is a four cylinder engine with overhead cam 3 x 4? 14 HP at 1200 rpm, which is quite a high speed for a Palmer engine. The VH probably is a new model, as it is featured on the cover. It has electric starting. The TM is back.


Deleted-The three-port engines except for Q1 and Q2.Additions-The YT1 and YT2. The YT (for Yacht Tender) is a small four cycle engine with push-rod operated overhead valves. The YT1 had been advertised as beginning in production in December, 1921. A Palmer advertisement in April 1924 announced the 'New 1924 YT-2,' so the YT-2 may not actually have been produced in 1922. The RW2 and RW4 have been added. The VHL which is like the VH except for ?' larger bore (3? x 4?).


Deleted - The D and the RW series. The last of the three-port engines. The model C, a two-port, is the only two-cycle still shown.

Additions-The ZR, built in 1,2, 3, and 4 cylinder models. This engine is like the NR T-head except that bore is increased to 5?' (5?x6) and the engine has been given a removable cylinder head. Palmer claims decreased combustion chamber area, increased compression ratio, and higher rated speed. They point out that the head can be removed without breaking any water connections. The ZR will prove to be a most successful engine and the 'Cadillac of Work Boat Engines.'

The early ZR3 and ZR4 had gear-type coolant pumps. They sometimes lost prime and were easily fouled by debris, so Palmer soon reverted to their usual plunger pumps. There also was a problem with air pockets in the cylinder head, so a change was made to all ZR engines to discharge coolant from the very top of the head, then down to the exhaust flange or exhaust manifold. These variations can help to identify early model ZR's.


Deleted-All NL engines except the NL1. The YT2.TheVH.Additions-The PB6 (Play Boy Six) L-head engine with dual ignition and the exhaust manifold cast in the cylinder block. Also added was the LH (Little Husky), an L-head four cylinder with magneto and impulse coupling standard.Changes-The NR has become the PNR (Palmer New R)with removable head like the ZR.

1937: For some years, the Palmer catalog was loose-leaf in a green binder, undated. Such a catalog is not trustworthy, as pages can be removed without it showing. 1 will list the models offered in 1937 based on a dated price sheet. Only the new models are highlighted:

The YT1. The LH or Little Husky, L-head 4 cylinder. The HH or Half Husky two cylinder. The PAL, L-head 4 cylinder with electric starting designed in, enclosed flywheel, and dual ignition (PAL stood for PAlmer-Lycombing). It was their first conversion. The name was sometimes spelled Pal. The Power Boy 6 (formerly called Play Boy Six). The SK6 (Storm King Six), a larger L-head six. The GW6 Green Witch Six. An even larger L-head six, also with dual ignition. The ZR series. The PNR series. The F series. The NK series. I have listed the Pal in the table even though it was a conversion as it was very important during WWII.

Production of the C had ended in 1930. It had remained nearly unchanged since 1900. The minor changes that were made over the years were: the design of the lower cylinder, replacement of the mixing valve by a check valve and a Schebler model D or a Kingston '5-ball' carburetor about 1906, and the new water pump already mentioned.


Additions-A marine conversion of the Ford Model A-B engine. I have loose sheets that show a stratified-charge Ford A-B and a Ford V8 conversion.Changes-The LLH (Big Husky) is offered in addition to the LH. It has the bore increased ?'. The LLH was actually introduced in 1932 according to advertisements.


Deleted-The Ford conversion.

Additions-Diesels: the RND4, RND6, and RND1 (the latter a stationary engine).The PH6 which is a marine conversion of a Hercules engine.

Changes- The SK6, GW4, and GW6 are noted as 'custom built' as though none were built for stock.

1947?: Palmer had developed their diesel series prior to WWII. However, the government gave Palmer the war assignment of building the PAL engine, for lifeboats, and they built about 11 per day. They also built a few hundred of the GW-4 and GW-6 for the Navy.

The company had been managed for some years by Carl Hathaway, a son-in-law of Frank Palmer. He sold the company to Columbia Air Products in 1945 and they changed the name to Palmer Engine Company. The company went bankrupt in 1947 and a group of senior employees bought the company at auction in November 1947.

The post-war catalog is a two-color sheet, undated. The engines shown are:

The RND6, RND4, diesel marine engines (plus 1, 2, and 3 cylinder stationary versions of the diesel), the YT1, the ZR models, and the PH-45, PH-75, and PH-120 which were marine conversions of International Harvester engines. We know that the YT1 will be replaced by the BH in 1948 and the BH will be replaced by the PW-27 (a conversion of a Wisconsin engine) in 1957.

Dick Day tells me that Julius Ulrich designed the YT1 and YT2 when he first joined the company. The YT1 was very popular but the YT2 much less so. All the engines that followed until 1950 were his work; the BH was his last. BHT, BHW, and BH-25 engines can be found; these numbers represent minor engineering changes.

Palmer continued with conversions of International Harvester engines and the one Wisconsin engine. The company closed its doors for the last time in 1973.


1.  Palmer was one of the earliest and the most successful of the American builders of two-cycle engines.

2.   They introduced a line of three-port engines in 1906. To please more customers, these engines were built both with jump spark and make and break.

3.  Beginning in 1912, they converted their four cycle medium and heavy duty line to T-head. The design may have been chosen because it was easier to cast. There were several T-head cars at that time.

4.  1917-1926 was a period when a ridiculous number of variations of the bore and stroke of the basic NL and NR engines were produced.

5. The 1930's was a period when high-speed four and six cylinder engines were developed, followed by the diesels.

6.  Real engine design ended at Palmer after 1948 with the BH.

Acknowledgement: I am most grateful to Dick Day, not just for loaning the catalogs, but for his critique of my early drafts and supplying many interesting bits of information about the Palmer Brothers and their engines.