Reply To: Thrust, hp, and weight comparisons

[Charles Myers]

An update for everyone.  Thanks to all who have posted advice.  To remind everyone, the problem was low speed at full throttle.  Through the club’s membership directory, I called the president of the Carolinas club chapter nearest to me (I live in Richmond VA).   He recommended another member at Smith Mountain Lake to look at the motor (1956 Evinrude Lark 30 HP).   I took the motor to him.  He did a complete refresh of the motor, including new seals and O-rings throughout, a new shift-rod bushing, a new impeller and impeller housing and impeller housing plate, a replacement flywheel (the puller threads stripped out of the old flywheel, and the flywheel had to be cut off),  removing and cleaning the carburetor, opening and cleaning the lower gear unit, sharpening and buffing the tips of the slow and fast carburetor needles, replacing the packing washers on the needles, replacing the sintered filter in the glass carburetor bowl, new copper core spark plug wires, new spark plugs, new coils, new points, and new condensers.   The gears in the lower unit are all good.  Did he find anything wrong?  One of the two bolts that hold the baffle in the exhaust chamber was loose and rattling around.  Under the flywheel on the port side there is an aluminum plate (photo) whose center  mounting hole had become worn and wallowed out.  That hole had an improvised large washer on the bottom side.  That washer was hitting something that prevented the armature plate from moving all the way to its stop at full throttle.  That was likely the cause of the low speed.  The plate has been replaced, and the armature now advances fully at full throttle.  When I went to pick the motor up to return it to the boat,  it was run in a water tank.  Once it is on the lake, normal tweaking of the slow and fast carburetor needles can be done.  I am looking forward to springtime to get the boat and motor back on the lake.  I will do an update post about how that goes.

While the pictured aluminum plate may have been the central culprit in the low speed problem, and while I did not set out to get a total refresh of the motor, I am vey happy it has been done.  It is confidence-building to know that all that has been done and that I can keep the 1956 motor married to the 1956 boat.

Thanks, again, for everyone’s input.