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Restoration Corner1950 Lauson S-350 Restoration
by Paul Moneski

Curator's note:  I was present at the 1999 Constantine, Michigan, Super Meet where Paul purchased this motor.  Paul traveled to the meet from his home in Maryland with his friends, brothers Robert & David Wagoner.  Robert drove his new Ford Expedition and they suggested to Paul that he attach the grubby old almost unidentifiable motor to the trailer hitch and drag it behind.  Robert finally relented and the motor made it back to Maryland, grease and grime intact.

Restoration of my 1950 Lauson S-350 3 h.p. outboard motor (S/N 13819) purchased at the Constantine, MI, meet earlier this year.

Here are a few pictures of the finished motor and the work as it progressed.




My Comments on the Restoration --

    The recoil spring was broken.  Lauson internal parts were bought
     from Martin Motors and are interchangeable with Martin "20", "40",
     "45", "60", and "75" starters.  Sometimes slight retrofitting may
     be necessary.


     Gaskets for these engines seem to be in short supply.  therefore, I
     cut my own from high-temperature material purchased from my local
     Western Auto Supply Store.  I always glue my gaskets with O.M.C.
     type "M" adhesive -- works well.


     Both the intake and the exhaust valves were reseated with a
     fine-valve (lapped in) grinding compound while they were still in
     the engine.


     The original gear foot seals were well worn and were replaced.

         Replacements:    Chicago Rawhide Brand.
                    Prop shaft seal # C/R 4985 (1 needed)
                    Drive Shaft Seal # C/R 4912 (2 needed)

     These parts were obtained from my local Applied Technologies
     (formerly Bearings Incorporated) supplier -- they are a national


     The carb needed the usual cleaning, etc.  However, the float needle
     was scored at its seating taper.  I used my Dremel drill tool with
     360 - 400 grit wet or dry paper with oil until the groove was
     polished out.


     It looks to me like Lauson bought their gear sets from the same
     supplier that Mercury did.  The prop. gear is the same as was used
     on early Merc. singles -- 2 thru 3.2 h.p.  The pinion gear differs
     only in that its internal spline is that of older Scott Atwater
     Bail-O-Matic drive shafts.  What a small world!

     Also, it appears to me that Lauson bought propeller shafts from
     Martin and drilled their own holes for gears and shear pins --
     Martin "40" or "45" shafts.


     The lower end of the drive shaft was worn.  REMEDY:  Flip the drive
     shaft over 180 degrees.  The original lower unit end of the drive
     shaft is undercut to less that 1/2".  Over time, leaking gear
     housings cause a lot of drive-shaft-surface and bearing wear,
     creating a loose fit.  The crank shaft end of the drive shaft is
     not undercut and is at a full 1/2" diameter.  Flipping the drive
     shaft and drilling the lower unit drive shaft bearing with a 1/2"
     drill bit should make a good retrofit job.


     Thank goodness that Lauson used treated aluminum (PARKER METAL
     PROCESS) for the construction of their fuel tanks.  This treatment
     resists much corrosion, unlike many other brands of gas tanks.
     Also, Lauson tanks are soldered together rather than being welded
     -- makes for easier repair work.

     The inside of my tank was coated with lots of BLACK GOOK!  Most of
     the conventional cleaners tried didn't budge the stuff.  YUK!  I
     resorted to using ideas from my old chemical days:  Good old
     Spic-N-Span in hot water -- lots of soaking --works well.

     See photo of tank in Fran's laundry tub.  (Don't tell her what I

     Note:  If you have a Lauson outboard with a missing gas cap, you
     can substitute one from an older Evinrude or Elto.


     There should be a 1/2 inch thick felt strip fitted between the gas
     tank bottom and the support housing.  Mine was somewhere else,
     i.e., missing..  The strip is designed for proper air flow
     (cooling).  Some fabric stores stock this material.


     Good grades of automotive or marine lacquers should be used:  Blue
     top coat, primer, clear coat and silver.  Spray cans offer minimum


     I used lacquer-made water-applied decals.  They are good!  overcoat
     decals with clear lacquer after they have dried for 72 hours.

     A good source for many different kinds of decals can be obtained
     from American Outboard of Cordova, MD (AOMCI Member).

          Contact Ms. Dora Kawalek at 410-822-1740.

                         LET'S GO BOATING!

                              Best Regards,

                              Paul Moneski