Jack Craib's Rowboat Motor Information Site

Skegless Evinrude
Rowboat Motors
An Article by Jason Harrison
2008

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1909-1912 Evinrude Rowboat Motors

by  Jason G. Harrison

In the following article, I want to focus on what are normally termed "skegless" Evinrude's.  In the infancy of the Evinrude Company, these skegless motors were produced to satisfy the fast growing demand for an easy to start, easy to transport, motor to propel the common row boats of the day.

The resulting engine was what the majority of later motor manufactures based their engines design upon.  These early versions of the Evinrude have unique features found on them that are not found on other Evinrudes of a later vintage.  With that said, I will try and show you the various nuances found on these early versions.

No better place to start than at the beginning, so let's go back to 1906.  For the last few years Ole had been making engines of various designs for different applications.  He started several businesses and was partners in others making engines to power horseless carriages, etc...but none of these businesses made much money and they all failed.

    Ole, now somewhat depressed at his failure at these various enterprises, fell back on a skill he had acquired over the years that had always paid the bills for him, and that was pattern making.  Around this time, the now famous "ice cream" story happened.  As we all know the story too well; Ole Evinrude and Bess Cary went on a Sunday picnic with some other friends at Lake Okauchee.  After lunch, Bess thought it would be nice to have some ice cream.  Ole, not wanting to let down his gal, took it upon himself to row a boat across the lake to a local place called Schatz's to buy this ice cream.  Due to the distance involved and the hot August temperatures, no matter how hard Ole rowed that boat, he couldn't get back to Bess in time before the ice cream melted.

    It was this very incident that triggered a though in Ole's mind, why not use some of his left over engine parts to create an engine to power a boat.  This though, this idea, burned in Ole's mind for a few years.   He was busy making ends meet to support his wife and new son, Ralph.  In his spare time, he began to piece together a workable power plant to power a rowboat.

    Eventually, the engine was done enough for a trial run.  Ole and one of his brother-in-laws, Russ Cary, took the engine to the Kinnikinnic River.  There they rented a boat for 50 cents.  They clamped the motor on the stern and fired it up.  Soon, the noise and clatter of the engine running drew attention.  The little rowboat was powering down the river and as it passed by a coal boat, the crew on that boat ran to the gunnels and cheered as this little motor pushed the boat right along.  Ole was delighted his little contraption drew positive praise from others.  This was the beginning of a revolution among marine engines.

    Taking some of Bess's criticisms of the new motor to heart, Ole redesigned this first engine some, cleaning up its appearance and making for a nicer motor.  This SECOND motor is what all modern day outboards motors based their design upon.  Vertical Crankshaft, horizontal flywheel, and a set of bevel gears are the basic engineering basis of modern engines today, just like Ole's engine.  This motor was the catalyst to an unexpected series of events in the Evinrude's lives to come.  Little did Ole know what he was starting, he just followed his instincts and satisfied his own curiosity.  The following picture is of the 12th outboard engine Ole made in 1910.  This motor shows the beginning of his now famous rowboat motor engines in its basic early state.

This story took place in 1908 and early 1909.  Once Bess realized the huge potential of this contraption, she encouraged Ole to build more.  Ole soon bought and made enough parts for 25 complete engines.  He fully didn't expect to need all the parts right away, bit it was cost effective to order and machine these parts in a lump sum.  Upon loaning this new engine to a friend whom used it one day, the friend came back with orders for ten more engines, thus the production of Evinrude engines began.  it is documented that 25 engines were sold in this first year, 1909.  One  unique item that seems to be used on the very early motors is the tilt quadrant arm.  Notice the SINGLE tilt quadrant arm.  This arm travels through a guide that is attached to the drive shaft housing.   It appears that only the earliest of motors had this feature for sometime in early 1910 this feature was changed to the dual arm that was used from then on. On all known variants of Evinrude rowboat motors known today, two tilt quadrant arms are used to adjust the tile angle of the engine on the transom of a boat.

    Now were at the end of 1909, and the demand for his engines grew even more; and Ole kept refining his idea to better the engines performance and looks.  True mass production of outboards didn't occur until 1910.  With money being spent on ads showing their new invention, production grew to feed the demand for this motor.

   To this date, there are only a scant few documented 1910 Evinrude's.  (Note of course there can be others as I am speaking of motors that I know of personally, or engines that other club members know about.)

    We do not know for sure if ALL the 1910 motors had the same features and Ole constantly changed his design to better the engine.  To begin this description, let's start with the lower unit. 

On all pre 1913 Evinrude rowboat motors, the lower unit has no skeg, or fin, on the bottom of the lower unit.  There are differences through out the years of production from 1910-1912.  On the very early versions of motors form 09-1910, the engines had a unique water pump.

The picture shown is of motor #705's lower unit.  Notice the water pump's shape.  For those that are not familiar with these types of motors the water pump is on the right side of the picture.  The vertical casting that runs perpendicular to the prop shaft on the front portion of the lower unit contains a brass plunger that rides along the prop shaft.  A cam on the shaft actuates the plunger, causing it to go down (drawing in the water) and then up (pushing the water up to the power head).  In this operation, a check valve must be in place to keep the water from being pushed back out and not used.  On this early version, notice the 90 degree fitting protruding out from the casting.  This is the check valve that regulates the flow of water in and also keeps the drawn in water from being forced out on the upstroke of the plunger in the water pump.  This check valve was not "custom" made by Ole.  There is a marking o this particular fitting that says "CRANE".  The name denotes a plumbing business that was around at this time in history.  One can easily understand the concept of why re-invent the wheel.  Ole probably bought this item off the shelf form a plumbing or hardware store, and adapted it to use on this engine.

    It is not known exactly when the pump style was changed, but at some point in 1910, engines came equipped with a different style of water pump.

Notice the lower units water pump is located on the right side of the picture.  This type of pump utilizes a cast-in check valve assembly and that is clearly shown as the short vertical casting on the very leading edge of the water pump.  The screw in plugs on top of both castings made for easy access to both the check valve and the plunger itself.  This pump assembly was cast in house by Evinrude and eliminated the need to buy aftermarket check valves, like those used on the earlier engines.

    Due to the fact there are so few known documented 1910 engines, I will now illustrate other known parts shared by engines from late 1910 and a large portion of 1911.  Again, let me start on the lower unit. 

Lower units for skegless Evinrude's came in two types.  First type was used on 1909 through engines made in late 1911, it is my belief they were used up to Aug. 22, 1911, but I can't prove that yet.  These lower units are unique to these years only.

The adjustment screw is now located on the leading edge of the bullet or nose of the lower unit.  Notice also the set screw to hold it in place that is located directly above the large screw.  The upper screw above all of this is again to secure the water pump assembly.

    Moving to the rear portion of the lower unit, ONE main feature must be noted.  ALL skegless Evinrude rowboat motors have this feature.  The rear plate of the lower unit is attached to the gear foot by TWO screws.  No other year Evinrude rowboat motor had this set up.  The following picture displays the two bolt's location in these early lower units.

With the lower unit covered, lets move up the engine to another area. 

It has been found that there are a few examples of engines that display different types of tiller yoke assemblies.  What I am referring to as the tiller yoke is the cast piece that the tiller handle attaches itself to, that in turn is attached to the driveshaft housing, which when moved from side to side, rotates the lower unit to go in the desired direction of travel.

    On some of the very earliest known motors, this piece was cast in brass, while yet other engines just some few hundred serial numbers behind them carry cast iron tiller yokes.

What makes this interesting is the fact that Evinrude would use brass tiller yokes, then switch to cast iron, then in late 1911 and through 1912 and from then on, go back to using BRASS once again for the tiller yokes.  The reason for this remains somewhat a mystery as we do not know nor do we understand why this occurred.  Not only are the materials different, but also there is a difference in some examples as how the tiller is attached and also what style of tiller handle was used.  The use of the cast iron tiller yokes was relatively short lived with known examples from 1910 through early 1911.  On motors after Aug. 1911, the use of brass was common place as the material for the tiller yoke.  It could be as simple an explanation as what ever material was handy was used.

    Tiller handles themselves have been found to be made in a different material as well.  Again, the reason for this is unknown.  Nor can it be documented at this time that a specific serial number range of engines use certain materials.  There are some known motors that have the commonly accepted appearing tiller handle, but cast in IRON, yet there are others that are cast in brass.  Some of these examples utilized a tiller handle that had a female end cast in the end of the handle.  This female end, joined with the male end of the flat bar on the tiller yoke assembly.

A variation of this has been documented.  That piece bore a tiller yoke assembly that had a hole machined into it to accept either a threaded metal rod tiller handle or a wooden version.  No specific's can be given as to why this occurred, nor can I say with any degree of certainty why again, such a change would occur?  Perhaps items were broken, replaced, or upgraded; this is another mystery as yet to be solved.

    Some of the earliest known motors to be documented were found to carry transom screws with hexagonal heads.  These transom screws were used to tighten the motor upon the boats transom.  At some unknown time, Evinrude did some more changing and the result of this was two known types of transom screws.  The hexagonal head shaped version and the standard thumb screw version are shown here

Moving up the engine, the next area to be covered is the crankcase.  As is the case with all Evinrude rowboat motors, the crankcase is cast in two pieces.  The upper half, which as the main bearing;  the lower half, which has the lower main bearing.  There was a subtle change in the actual casting on the crankcases done after Aug. 1911 engines.  ALL the documented ORIGINAL examples of the motors prior to Aug. 1911 have one style of crankcase.

    The areas that one should focus in on are the lower half of the crankcase.  Concentrate your attention on the casting ribs on the lower portion of the crankcase.  See how these ribs support the crankcase itself?  Notice the distance they travel up the crankcase as well as the actual size of the ribs themselves.  This style of crankcase is only found on pre Aug. 22, 1911 engines.

Post Aug. 22, 1911 engines carried a different crankcase.  The change occurred in the casting ribs on the lower half.  Notice now how much FURTHER up the ribs go supporting the crankcase.  They are also much larger in actual size than the earlier versions.

The cylinder's used on skegless engines are also unique.  The spark plug hole on all skegless Evinrude engines is the type that uses a 1/2" pipe thread spark plug.  Later engines (non skegless) changed this hole size and went to a 7/8" spark plug hole.

    Continuing on up the engine a prominent and unique feature on early Evinrude's is the exhaust manifold.  In engines from the time period of 1909 through Aug. 1911, the exhaust manifold used was smooth, with no name or numbers cast into the side.

On this particular motor, the brass exhaust can is held in place between two cast iron plates which serve as the top and bottom plates of the can itself.  The two bolts connecting the top of the can to the manifold extend down the length of the brass can and go through the bottom iron plate, where they are secured by two nuts.

    Late in 1911 Evinrude changed how the exhaust can was secured to the manifold.  This change eliminated the two bolt system and instead went to a single bolt attachment.  This single bolt's location was moved to the center of the can and as the earlier model, a threaded rod extended down through the can and was secured via a nut on the bottom end of the lower plate.

The main bolt I am speaking of is the one going through the center of the manifolds casting in the upper portion of the picture, secured with the brass nut.  The lower plate on this late style exhaust was not longer cast iron, instead, the material changed to brass or bronze.

    In addition to how the exhaust can was secured, Evinrude also changed the side appearance tot he actual manifold itself.  In post Aug. 1911 made engines, the manifold was cast with the name EVINRUDE in the side.

This style of manifold was used through the rest of 1912.  It was no longer used after that date.  (Note:  The Canoe versions of Evinrude motors used this same style casting on their manifolds, but where the can mounted was different, so it is unique.)

    There was also a difference in the brass muffler cans used on the engines.  Pre Aug. 22, 1911 engines were equipped with the single triangle shaped series of holes to allow some of the exhaust out of the can.  Post Aug. 22, 1911 engines had two sets of triangular shaped holes, one above the other.

Post Aug, 1911 can

Pre Aug, 1911 can

On this carb you can clearly see the addition to the knurled wheel or knob to adjust the valve lift and the rod sticking up to provide friction to hold the adjustment in place.  A common feature on ALL skegless models is that none of the motors had a fuel shut off valve between the carb and the gas tank.  This function was enabled by simply closing the mixture valve on the carb itself.

    The gas tanks used on skegless Evinrudes were all the same.  They are unique in that their size and fuel cap are different than on later models.  The fuel fill cap is quite small on skegless Evinrudes, measuring around 3/4".

(NOTE:  In 1913 a motor (which is, of course, not a skegless Evinrude) had a gas tank with this same small cap and small fuel opening, but the tank itself was much larger. 

The fuel capacity of the early skegless tanks was 3 quarts. 

It is important to remember that, to date, NO ORIGINAL motor has ever been found to carry a decal on the gas tank.

  Many of the pictures shown in this article contain views of the fuel tank that has decals on it.  It was believed to be correct in years past, but now as more evidence has been uncovered; it is thought that the skegless Evinrude engines never wore a decal on the tank.  I have various original pictures from the Evinrude factory and NONE of these pictures show an engine with a decal.  Further evidence supports this as shown by a picture taken at a New York Boat show in 1912 as well as a picture taken in 1911.  The evidence is really beginning to mount in support of no decals and thus I thought it was important to note that.

Every production made Evinrude rowboat motor came equipped from the factory wearing an identification plate fixed to the top of the gas tank.  This i.d. plate on skegless motors was made of brass and on it was stamped the engines serial number.  On engines made prior to Aug. 1911, the tag was like this.

On the lower right hand corner of the i.d. tag, the engines serial number was stamped.  That number is quite important and will really help nail down the correct vintage of the given motor.

On engines made after Aug. 1911 through 1912, the tags were changed and they appeared as this.

Due to the increased diameter in the flywheel on engines post Aug. 22, 1911, the flywheel partially covers the i.d. tag.  The bottom portion of the tag reads as follows, "AND PRINCIPAL FOREIGN COUNTRIES".

    There are several known motors that are missing their i.d. tags.  We can only guess as to the year of these motors.  Fortunately, due to the parts variances that we can now identify to certain years, the year of the motor can pretty well be guessed, but that is as close as we can get to legitimately documenting the motor to its correct vintage.

    The brass casting that funnels the fuel OUT of the tank and into the fuel line was unique on engines made prior to the Aug 11, 1911 patent date.  On those engines, the face of the brass funnel casting bore NO casting marks.

Engines made after Aug. 11, 1911 were equipped with a casting that had a casting number of "39A" in its face.  This same basic piece was then used on the rest of the standard rowboat motors Evinrude made.

The flywheels used on skegless motors were unique as well, as they did CHANGE in the years of their production.  On engines from 1909-1911 the diameter of the flywheel was 9 inches.  In 1912 the diameter increased to 9 1/4".  All the flywheels had a nickel plated rim.  An important feature to remember is that NONE of the skegless Evinrude's flywheels had any identification marks or letters cast into the flywheel.  The face of the flywheel was bare.  This picture shows the lack of any letters or numbers on the face of the flywheel.

Due to a recent discovery in some Evinrude literature, we now have a more definitive break down of early engine production.  The following chart shows the serial number break down for each year they were made.  It should be noted that there have been found a few anomalies to this chart.  Two engines have been found to carry a serial number higher than what is listed in this chart.  It should also be noted that Evinrude made canoe motors and their numbers may or may not be included in this break down of serial numbers.

1909  No documentation as to if these engines received any serial numbers

1910  Serial numbers range from:  #1-1000

1911  Serial numbers range from:  #1001-3090

1912  Serial numbers range from:  #3091-7740

    There are many theories about these old motors, and without further investigation, they are just that, theories.  Perhaps with more research, these theories can be proven one way or the other, and a follow up article may well be in order.  I do hope that this article points out some of the characteristics of these early engines and enables fellow collectors to better understand the earliest of all Evinrude engines.  It is an  unfortunate fact that there are known examples of motors out there that have been "pieced" together and thus do not represent authentic Skegless Evinrude engines.  Some of these engines may well have been changed back in the day to keep the motor running with what ever parts they could obtain.  There are also motors known to exist where the changes were done in more modern times to make a motor appear early, when in all actuality, it's an unfortunate "fake".  With the information provided, it is hoped that members will gain some knowledge and arm themselves so that they will better understand the variances found in these rare engines.

    A special respect is rightly deserved to these wonderful early Evinrudes.  Little did Ole Evinrude know that when he first swung the flywheel on his little invention;  the resulting bark of the exhaust would be a sounding note that would be constantly echoed through the years with millions of Outboard Motors in daily use around the world.  What a sound that is!