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Link and sync

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mo3444

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I am trying to perform a Link and Sync on a 83 OMC V4 115hp eng. With all of the linkages (cables) disconnected I am unable to get the throttle arm to remain in the idle position so that the idle adjust screw will come in contact with the contact point on the eng. case. Something seems to be pulling the arm to the full throttle position. Should there be a return spring that holds the arm in the idle position or is this a function of the throttle cable? Eng was rebuilt and I am not sure everything was put back together properly.
 
If you are speaking of the long vertical throttle arm which has the throttle cable cannect at thr bottom and the top portion connected via a link to the timer base.... there is nothing designed on that engine to hold the throttle/timing at the full throttle setting.

The vertical throttle are is a two piece unit that has a rather large coiled spring between the two, BUT that spring is designed to return that throttle arm to a normal straight up and down position. Sounds like you have something installed improperly.
 
Joe, That is the arm I am speaking of. I think I must have something installed wrong. I guess what you are saying is that that arm should have some pre-load on it that holds it in a vertical position correct? Any idea what I could have wrong that would cause this.
 
mo3444 said:
Joe, That is the arm I am speaking of. I think I must have something installed wrong. I guess what you are saying is that that arm should have some pre-load on it that holds it in a vertical position correct? Any idea what I could have wrong that would cause this.
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I suspect that the large round shaped coiled spring that holds the two section of that arm together when it's off the engine is installed improperly.

Remove the vertical throttle arm from the engine and set it on your work bench, then remove the spring. Now, study the three parts.... there is only one way that spring can be installed that will allow the long top portion to pull away (forward) from the lower portion and have the top portion spring back to a vertical position when released.

And since there is only two ways that spring can be laid and hooked on the the smaller lower portion first, one of the ways has to be correct. Let us know what you find.
 
Joe, I thought I looked at the two arms you are referring to and found that no matter how the spring was installed I got the same result. I will revisit this issure. Just to be clear, the arm should be pressed back so that the idle adjustment screw will be in contact with the contact point on the engine case until the throttle is advanced?
 
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When the vertical throttle arm is assembled correctly, the entire arm moves as a unit (as if it were one piece) moving the timer base under the flywheel and the carburetor throttle cam roller at the same time.

BUT when the timer base has advanced to the full spark advance point (up against the rubber stop), the top portion stops moving of course... and from that point on, only the bottom portion of the vertical throttle arm moves, advancing the carburetor butterflies only via the cam roller.
 
Joe you are absolutely correct. I went to my storage and checked out the operation on an old parts motor I have there. I know now that the problem I am having is related to my throttle cable and it's proper travel distance. It appears to me that the push rod from the throttle, when adjusted properly and in the neutral position , will hold the throttle arm in the position it needs to be in. (resting with the idle screw in contact with the eng. case) As the throttle is advanced it does what you described. I have had my throttle cables and the throttle quardant replaced. What I have discovered is when I adjust the trunion nut to a point where the throttle arm is in the correct position, there is not enough travel when the throttle is placed in the wot position for the carb butterflys to open completly. I am only getting about 3/4 open. My plan is to dive into the throttle quadrant to see if I can somehow get more travel. Please advise if I am looking at this correctly.
 
The proper manner in which to start the throttle cable adjustment procedure is to firts have the engine in neutral with the vertical throttle lever in the idle position..... then with the control box in neutral, adjust the throttle cable trunion so that it lines up with the clamp in tunnel and the cable end aligns with the bottom of the vertical throttle (Starting Point). Is this what you're doing?

Double check to make sure that you do not have the cables reversed.

As you move the shift throttle lever on the control box, the very first cable to move is the shift cable.
 
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