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1968 18 HP Evinrude ignition timing

T

tgregorybrooks

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"Is it possible for the igniti

"Is it possible for the ignition timing to be off and if so, how is it adjusted.

I have replaced every component of the ignition, removed wobble from the armature plate, rebuilt the carb, and still am having low power output."
 
"Timing is set by the flywheel

"Timing is set by the flywheel key aligning with the crankshaft slot/flywheel slot.

Unless that key is sheared, the engine is in time.

Greg, you'll need to explain the problem more in detail if possible.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"Here is a summary that will h

"Here is a summary that will hopefully fill you in on everything I have done so far.

I have replaced the plugs, wires, points, condenser, and coil.
The champion plugs are gaped to .030
The points are gaped to .020.
The carb has been rebuilt. I disassembled it completely including jets, tubes, seats, needles etc and soaked in carb cleaner. After removing from the carb cleaner, I rinsed with gasoline. Then I blew out every orifice with compressed air.
I checked the compression and get about 95 psi in one cylinder and 98 psi in the other.
I checked the spark and it is hot blue and jumps a 3/8" gap no problem.

I worked on the motor this afternoon to double check everything and made an interesting discovery. When the throttle is turned to full so that the stop on the armature plate hits the stop on the shift inter lock and the throttle cam is at the max, the throttle valve goes beyond horizontal in the carb throat and continues until it is about 1/3 closed.

Is this normal or should the the throttle valve be stopping in a horizontal position? It seems to me that this could certainly decrease performance but I can not see how it could be adjusted.

Thanks for all your suggestions so far."
 
"At full throttle, where the t

"At full throttle, where the throttle control cannot be moved any further, the throttle butterfly must be perfectly horizontal. I cannot recall the adjustment procedure at the moment on that model, and the alarm is set so I can't get at the books. I'll look into it tomorrow and get back to you."
 
"I loosened the cam, actually

"I loosened the cam, actually took it off so that I could look at it and understand how the adjustment worked. The bolt at the high speed end goes though a hole so that end cannot really be adjusted. The bolt at the low speed end goes through a slot so there is about 1/4" of adjustment on that end. If I slide the low speed end of the cam out all the way it obviously increased the low speed throttle actuation. It also caused the high speed end to pivot in some so it slightly decreases the high speed actuation but not enough to keep the throttle valve from over rotating.

It does not seem right that I would have to create a slot at the high speed bolt hole on the cam but any suggestions would be great."
 
"The cam has a scribe mark on

"The cam has a scribe mark on it. The roller should make contact with the cam when that scribe mark is dead center of the roller. However, whether this alignment is correct or not, this would not cause the throttle butterfly to pass the wide open throttle (horizontal) position at the full throttle setting.

The 1968 18hp carburetor throttle shaft is equipped with a permanent link on the end of the butterfly shaft that the linkage rod connects to, there is no adjustment. That linkage rod connects directly to the throttle roller arm shaft. For the throttle butterfly to exceed the horizontal position with this setup, either the linkage rod is wrong (too long) or the throttle roller shaft assembly has been bent, something of that nature.

Is it possible that another carburetor has been installed, one that has a separate linkage arm that attached to the end of the throttle butterfly shaft with a set screw? If so, make a proper adjustment at that position.

You state that the engine is a 1968 18hp Evinrude. What is the model number of that engine?"
 
"It is an 18802M.

The link

"It is an 18802M.

The linkage arm is permanently "swaged" on to the throttle shaft so it cannot be adjusted. I checked the linkage length against a 1966 18HP that I have and the length of linkage is the same. Bending the roller arm (twisiting) would be a solution that I can see working I was just a little reluctant to do that without some input/ opinions.

If it helps, I can send a photo of the carb/ linkage."
 
A picture or two might help. W

A picture or two might help. Wonder if possibly a different armature plate or cam might have been installed. I'll take another look at the books.
 
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