The YT-1 and YT-2 Marine Engines

Marine Engine

YT-1 1922-1924 style intake 1938 engine.

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Jr. 40021 Ben Morgan Road Leonardtown, Maryland 20650-2521. Copyright retained.

In my opinion, the two most sought-after antique marine engines are the Palmer Bros, of Cos Cob, Connecticut, models YT-1 and YT-2. The YT stood for 'Yacht Tender.' They were widely used in that application, but they also were popular with working watermen. These engines are beautifully running at very low speed, small, lightweight, and it's fun to watch all the motion. They have exposed overhead valves and an exposed eccentric and strap operating the water pump plunger. A few have magnetos but most have Cuno timers with T Ford 'Buzz' coils for ignition.

Around the Chesapeake Bay, the YT-1 was a popular engine for small crabbing skiffs. This was probably due to the much better fuel consumption of a four-cycle engine over the turn of the century two-cycle engines that had powered many of the watercraft favored by the watermen.

The YT-1 was released for sale in December 1921 and was made until 1947. By the 1920s the watermen were replacing their two-cycle engines with new four-cycle engines as most of the early engines were long since beyond reasonable repair. On the other hand, the two-cycle marine engine with make and break ignition held on in the Canadian Maritimes up until at least the mid-1960s. I believe this was due in a major part to the area weather conditions, and often the watermen had essentially open boats. The proven reliability of the low voltage make and break ignition over jump spark under adverse weather conditions demanded a waterman stick with proven technology. It is true four-cycle marine engines were made with make and break ignition, however I don't believe they were commonly made after the early 1930s, particularly in the sizes needed by watermen. A two-cycle M&B marine engine is still made in limited production in Lunenburg, Nova Scotia.

The ignition system was the most troublesome portion of the marine engine. Dampness and water, particularly salt water, corrosion were two very active participants in the daily lives of watermen. One of the ways watermen dealt with these two very troublesome problems was they would put the 'Buzz' or M&B coil along with the battery in a small wooden box. The cover or lid was arranged so water would not run into the box. The two or three wires to the engine would be lead out of the box with the holes for the wires slanted down so water could not run down the wires into the box. Often the box would have a leather strap which the waterman could slip over his shoulder so he could carry the box home and put it by the kitchen stove to dry out during the night. This same setup is also great for running marine engines at shows.

The YT-1 developed 2 HP at 800 rpm. It swung a three-blade, 12' diameter by 10' pitch prop, weight 130 lbs., bore 3', stroke 3?.' There were two flywheel diameters. Some early YT's had flywheels 11' diameter, and later units had 12' diameter flywheels.

In 1936 the YT-1 cost $ 100, magneto $35 extra, clutch $45 extra. Needless to say, most watermen bought them without the clutch or magneto.

Only one out of thirteen known YT-1 engines has a magneto. On the other hand, three out of four known YT-2's have magnetos. Apparently YT-2's tended to be bought by more affluent yachtsmen, rather than watermen. That may be the explanation for more magnetos on YT-2's than on YT-1's. I doubt we shall ever know the answer.

The YT-2 was essentially two YT-1's mounted back to back on one crank-case. It was made from 1924 until about 1928. Of the four YT-2's known to the author, three have 1924 manufacturing dates and one has no serial number. The last two digits of Palmer Bros, engine serial numbers are the year the engine was made. In the late 1960-1973 time frame, only the last digit is the year the engine was made. Considering that engines such as the Palmer Model C were made from 1900-1930 with very few changes, it is not possible to precisely identify the year of manufacture without the original serial number tag.

The YT-2 sales price is unknown. Trim such as carburetor, water pump, priming cups and drain cocks were the same as for the YT-1. Parts such as valves, valve springs, push rods, water pump, eccentric, etc. were the same as the YT-1. The cylinder head for YT-1 's made before 1924 had the spark plug facing aft at about 45 degrees. Because the spark plugs would interfere in the YT-2, the plugs had to be placed in a vertical orientation. This meant that YT-l's made after 1924 have their plugs vertical. Early YT's had 7/8' spark plugs, later YT's had 18mm plugs.

The YT-2 has an oil pump driven off the aft cylinder camshaft. It pumps oil to the forward crankshaft bearing from the aft sump. In the YT-1 the forward crankshaft bearing is oiled by a drip oiler and the crankcase is splash oiled in both the YT-1 and YT-2.

The magnetos for the YT-1 and YT-2 were American Bosch model FX-1 or 2 or FB-2ED-1-1c. Remember the YT-1 and 2 run counterclockwise facing the flywheel and the YT-2 fires at 90 degrees.

There were basically three different carburetors and intake manifolds used on the YT-1. The 3/4 inch Schebler Model D was used with the intake manifold shown in the photo marked 1922-1924. While the Schebler model was the standard carburetor offered by Palmer, individual owners may have tried other carburetors such as Kingston five ball, Krice, Monarch, etc. These owners were probably trying to get more speed or better fuel consumption.

The Mayer carburetor with an SAE style flange was used with intake manifold shown in the photo marked 1924-1940. It is believed the Mayer carburetor started out on the 1914 Buick automobile.

SPECIFICATIONS

Bore and Stroke3' x 39?'
Displacement, cu. inches25
Weight, lbs.130
Dimensions, Length overall, ins18
Width overall, ins12 ?
Width between timbers, ins8
Width between bolt centers, ins11?
Height, center of shaft to top of rockers, ins17 ?
Depth, center of shaft to rim of flywheel, ins6

CYLINDER--Special gray iron, ground and honed to size, ample cooling surface, intake pipe cast integral to heat mixture.

CYLINDER HEAD--Removable type, water jacketed

VALVES--Incorporated in head, interchangeable, non - corrosive steel.

PISTON--Hard gray iron, liberal length, fitted with three rings.

WRIST PIN--Carbon steel hardened and ground, hollow, full floating.

CONNECTING ROD -- Drop - forged, I beam construction, bronze back babbitted die cost bearings, nickel steel connecting rod bolts.

CRANK SHAFT--Drop-forged, counterbalanced, heat treated and ground.

BASE--Cast-iron, barrel type.

CRANK SHAFT BEARINGS--Bronze bock, babbitt lined.

CAMSHAFT--Drop - forged, with gears and corns integral, hardened and ground, bronze bearings.

ROCKER ARMS--Standard design, drop-forged, bronze bushed.

PUSH RODS--Steel, adjustable! fitted with boll and socket.

BALANCE WHEEL--Gray iron costing, machined to size, balanced, taper bored and keyed to crank shaft.

EXHAUST AND INTAKE--Exhaust outlet flanged to cylinder head and topped for 1' standard pipe. Intake cost integral with cylinder forming hot spot, flanged for carburetor.

WATER PUMP--Bronze, plunger type, eccentric driven.

IGNITION--Coil and timer for use with 6 volt battery is standard. Magneto may be supplied at additional cost.

CLUTCH AND REVERSE GEAR--Palmer type YCHS Available as extra equipment with machined sub base costing if desired.

With the passing of the Safe Boating Act in 1940, the Zenith marine carburetor, 61 series, was used. See photo marked 1940 intake. This carburetor is slightly different from the Zenith industrial version in that it has an intake throat slanted upward to keep gasoline from running out. when 'choking' the engine to start. A gasoline pickup tube, to clear the throat once the engine starts, is included. Provision to mount the backfire trap on the inlet to the throat is made. The industrial or marine carburetor works equally well, but DON'T use the industrial carburetor in a boat.

The photo showing the 1940 intake manifold should be compared with the photo showing the 1924-1940 intake flange. On occasion the carburetor end flange on the 1924-1940 manifold will be found with the holes slotted out to take the larger flange on the later Zenith 61 carburetor.

This damage may easily be overcome by filling in the slots with braze and reshaping and redrilling the flange. Some intake manifolds will be found where the carburetor does not sit level when the engine is sitting level. This is because to engine angle in the boat had necessitated bending the manifold to allow the carburetor to sit relatively level in the boat.

It is interesting to note Palmer catalogs of the period show a ?' pipe thread/SAE style flange with the Shebler, model D connected with a 'close' nipple without an external pipe as shown in the photo of the YT-1 made in 1998 from N.O.S. parts. This photo also shows the cast iron breather valve of the late 1930s and the expanded crankshaft boss of 1937. This boss permitted the use of modern LIP seals in place of the felt seals that had been in use before the invention of the LIP seal.

The felt seal had the serious drawback of absorbing the water and eroding the crankshaft. The change to LIP seals took place in 1937. A suitable replacement seal is Federal Mogul 476838.

It appears most YT-1 applications were without reverse gears. In the case of the four known YT-2's one had a Palmer-made base using a Joe Petrolli, so called 'Navy gear.' The other YT-2 with reverse gear has a Palmer model YC reverse gear.

There are a few other changes that will help to roughly date a YT-1 without a serial number. It may be noted that the 1922 engine serial number tag is located on the forward face of the cylinder just behind the drip oiler. Some time after 1924 Palmer began the practice of placing the serial number tag on the port crankcase mounting wing just aft of the carburetor. When the practice of placing the serial number tag off the cylinder (in a location not so easily lost, if the cylinder is replaced) began is not known at this time.

It is believed that a petcock was added to the aft starboard side of the crankcase to indicate correct oil level in the crankcase in about 1926.

It will be noted on the 1938 and 1947 engines there is a mounting bracket with a hole bored in it just behind the sector bracket of the Cuno timer. This seems to have appeared when the YT-2 was released for sale in 1924. This mounting bracket is cast into the crankcase and is used to mount the magneto gearbox. It should be noted that when the magneto is used, the camshaft has to be changed from the one used with the Cuno timer. The magneto drive bracket is not present on the 1922 YT-1.

There were a number of water outlet changes made on the cylinder head. The first version exhaust outlet was a 1' NPT boss. Cooling water discharge was a 3/8' NPT out the top of the head. When the YT-2 was released for sale, the exhaust boss was changed to a semi-triangular shape with 5/16' cap screws to hold the exhaust manifold against the two cylinder heads. Cooling water for the exhaust manifold passed from the cylinder heads into the exhaust manifold water jacket through 3/8' holes near the apex of the triangle. In the YT-1 application, the cylinder head had the same semi-triangular shaped boss, only in this case an adapter was provided having the same general shape as the exhaust boss. The adapter was approximately 1' thick and bored for 1' NPT exhaust pipe. The cooling water discharge was a 3/8' NPT in the top of the adapter which was, at some later date, changed to the cylinder head.

There were three types of crankcase breather valves. A mushroom style and a later cast iron unit shown on the '1998' engine replaced a small bronze check valve that dated back to at least the 1912 period. The purpose of the crankcase check valve in a one cylinder, closed crankcase four-cycle engine is to keep the oil in the crankcase from being forced out of any small opening such as around the valve tappets, crankshaft or camshaft bearings.

When the piston comes down it compresses the air in the crankcase unless there is a working check valve to allow the air to escape. When the piston rises, the check valve closes and a vacuum is created in the crankcase thus keeping the oil from leaking out of the engine. I have stressed working check valves because these valves tend to become dirty and sluggish in operation and while the engine runs well, it is going to lose oil at a rapid rate.

The cast iron breather needs to be cleaned occasionally. It is not as complicated as will appear on first inspection. There is a bronze valve that moves up and down with the piston motion. On the top side of the valve is a small piston that slides in and out of the top cap. There is a small phosphor bronze spring on top of the piston which returns the valve to the lower bumper. Don't lose it!

Immediately below the valve is a threaded rod with a neoprene bumper washer that limits the travel of the valve. This rod is extended through the bottom of the breather and it has a lock nut that keeps the rod from moving once it is locked down. When operating correctly there is a definite clapping sound. To adjust, loosen the lock nut and rotate the threaded shaft either way until the valve starts to 'clap.'

The simple old time bronze two-part check valve made far less noise, and if one can find one of them, they bolt to the same bolt spacing as the cast iron unit. Don't toss out the cast iron unit, as it would depreciate the value of the engine as an antique.

In conclusion, the author is constantly looking for differences in various early Palmer Bros, engines. It is most helpful if photos of all four sides are taken and serial numbers provided if known.