35 hp johnson overreving please help me

[david]

I finished rebuilding the ign

I finished rebuilding the ignition with new points coils and rebuilt my carb and now the boat motor runs great while idiling but after getting it up to a certain rpm is just leaps to wide open and i have to choke it out. I have my hand on the throttle control so i know the thrittle lever is not sticking but don't undertsand then where it would get all the gas to rev so high. I have not taken the boat out which i just bought for fear that it will stick while in gear. maybe somebody can help me out here
*crosses fingers*

 

[joereeves]

"David.... On the front of the

"David.... On the front of the magneto base plate, there is a "cam" that contacts the "roller" that opens the throttle butterfly. On that "cam" there is a scribe mark. The throttle butterfly should start to open when that scribe mark is in line with the center of the roller.... not before or after, but centered. This is refered to as synchronizing the carburetor (carb to ignition).

Now.... even when all is as it should be ie ignition, timing, synchronization, etc etc... the one thing you never want to do is to race the rpms on a outboard beyond a certain point. If you do, and if there is no automatic safety cut out, the air being drawn through the carburetor throat reaches a point whereas the upward motion of the pistons creates such a vaccum that it holds/locks the throttle butterfly in a wide open position. And that butterfly will stay there even when you close the throttle at the tiller handle or control box. There is a lock out lever/device in conjunction with the shift lever, leading up to the magneto timer base which should restrict the timing when the shift is in neutral... however, even that will not prevent a runaway engine when the engine's being run on a hose or in a barrel at times. Use caution.

Joe

"

 

[joereeves]

"David.... My apologies. I neg

"David.... My apologies. I neglected to pinpoint that this runaway condition exists only when racing the engine to excess in neutral, or when being run on a hose flushette or possibly a small barrel. It will not exist when you are actually in the water with the engine in gear. When in the water and in gear, the exhaust back pressure created due to the water being within the area of the engine that's in the water, coupled with the water pressure being exerted on the prop, it is impossible for the engine rpms to runaway as what you've experienced.

Joe

"

 

[steve]

I have the same problem as Da

I have the same problem as David (engine overreving while on a hose). This is a 1986 model 175H.P. Johnson. Since it did overrev should I change the water pump before going to the lake? I changes it last fall after boating season when I stored it for the winter. Thanks