February 11, 1963
Bulletin No. SB-941
Trouble Shooting
SUBJECT: Shorted Ignition Systems
18 H.P. Engines - Models FD-16 through 17M
We have received reports that water spray is being drawn into the area around the
powerhead on the subject 18 h.p. engines. This usually results in a shorted ignition
system. Another noticeable affect in salt water areas is the corrosive action of
salt water on unpainted metal parts under the shroud.
This situation does not necessarily occur on all of the subject 18 h.p. engines. It
seems only to be characteristic of certain conditions, or, of certain boat/motor
combinations that develop excessive amounts of water spray behind the boat when the
engine is operated at near full throttle.
A change has therefore been made to #308357 lower motor cover - replacing the ten (10)
small holes under the carburetor with one (1) oblong hole. This reduces velocity of
the air passing through the remaining small holes in 308357 cover, especially those
in the rear, preventing water spray induction.
This situation can similarly be relieved on any of the subject engines made prior to
the above mentioned change by drilling two holes in 308357 lower motor cover as follows.
(1) Remove starter housing and carburetor.
(2) Cover intake manifold opening into crank-
case with masking tape. THIS IS IMPORTANT.
(3) Locate centers for two holes - 1/2" in
front of and 5/16" to the outer sides of
the foremost air intake holes under the
carburetor. Figure 1.
Figure 1
