1968 evinrude 18 hp throttle timing question

[james__12345]

When I tried to adjust the throttle timing, even with the cam plate adjusted as far back as it will go, the butterfly still starts to open before the roller is between the marks. Are there any other places to make adjustments to help this? The only adjustment I've heard talked about is moving the cam plate in and out, but it won't move far enough. I've thought about drilling the slot out a little more to allow it to move back further, but I wanted to make sure there wasn't an easier fix first.

 

[HighTrim]

Re: 1968 evinrude 18 hp throttle timing question

Is your choke on?

 

[james__12345]

Re: 1968 evinrude 18 hp throttle timing question

No its not.

 

[james__12345]

Re: 1968 evinrude 18 hp throttle timing question

Now that I think about it, knowing that my lower unit is from a different year, I wonder if my carb is from a different motor too. Is it normal to have to take the plate with the silencer pad off the front of the carb in order to get it off the motor? Mine wouldn't clear the bolts holding it on, with out taking the two screws out of the front of that cover and removing it. Another reason I think that may be the issue is that the low speed needle is not set up the way it is in the diagram of my motor here Evinrude Carburetor Group Parts for 1968 18hp 18802M Outboard Motor parts number 71, 73, 74, and 75 are not there, and the needle it self 36 is longer than the one shown, and sticks out a hole drilled in the housing. I had assumed some part of the knob system had just broke, and they rigged up an extension on the needle, but now I wonder if its from a different motor all together.

 

[AlTn]

Re: 1968 evinrude 18 hp throttle timing question

do you have #18 and #79?...if so, #11 is the set screw to adjust the linkeage between the carb follower shaft and the throttle shaft

 

[james__12345]

Re: 1968 evinrude 18 hp throttle timing question

do you have #18 and #79?...if so, #11 is the set screw to adjust the linkeage between the carb follower shaft and the throttle shaft

I'm out of town for the week, so I'm basically going by memory and one picture I happened to have on my computer.

and naturally that part is covered by a bracket in the picture.

If i'm looking at the diagram right, and remembering the carb on my motor right, I was thinking that screw tightens against a flat spot on the shaft, so I didn't really think it was something that could be adjusted. Am I not seeing something right there?

 

[AlTn]

Re: 1968 evinrude 18 hp throttle timing question

there should be a bell crank on the throttle butterfly shaft that connects the linkage from the timing roller to that throttle shaft. That bell crank should have a set screw that allows adjustment of the linkage between the two: the movement of the carb roller shaft and the throttle shaft.

 

[james__12345]

Re: 1968 evinrude 18 hp throttle timing question

I am back home, and I checked the linkage you pointed out, but it does not adjust. Where the rod from the roller comes through that bracket it has a flat spot on it and there is a matching flat spot on the bracket. The rod can not be adjusted at that bracket. Here is a drawing of how it is.
The one on the left is how it would be if it were adjustable. The one on the right is how mine is. Red circle is the rod from the roller, yellow is the bar that goes to the butterfly, the grey part is the screw that holds the bracket on the rod from the roller.