July 28, 1959
Service Bulletin No. SB-729
Subject: OVERHEATING - 35 H.P. Models
Following are a few tips on where to look in case you have a 35 H.P. motor
that seems to overheat resulting in loss of rpms:
1. Check the water pump for defective impeller.
2. Check the air bleed hole in the water pump to be
sure that it is open.
3. Check the drive shaft to see if seal, part #305306
has worn a groove. With a groove worn in the
drive shaft at this point, it is impossible for
the water pump to deliver adequate water for cooling.
4. Check to be sure that #1000 Sealer had been used
between the top face of the gear case and the
impeller housing plate. With a leak here, there is
a possibility of exhaust gases getting into the water
recirculating system, resulting in too much air and
too little water for adequate cooling.
5. Check to determine that plug, part #300077, which
holds the water intake screen, part #302521, is
installed. If this plug is missing it is possible
that here too, exhaust gases can be introduced into
the cooling system.
If none of the above proves to be the trouble, then the entire cooling system
should be checked for possible flashing left in as a result of die casting.
NOTE: It is imperative that new cylinder head gaskets be installed whenever
the heads have been removed.
JOHNSON MOTORS
Jack Penland
Jack Penland
Service Department
JP:eb
Note: Post on 35 H.P. Index