How to adjust throttle cable engagement?

[NMShooter]

1988 85HP Force....

Took boat out for first run since all this carb cleaning / synchronization business. Ran great once warm. Best ever.

Still a bit of an issue though with the range of adjustment for the throttle. Would not start cold, and had to remove the ball joint linkage in order to get it to start. Once warm, throttle up through the power band was good, but it seems to stop well before it tops out. I am only able to get 4800 rpm with a 15 pitch prop at 4600' elevation with .072" jets.

I just received my shiny new, straight, roller shaft for the throttle cam. Will put it on tomorrow and see if the throw is improved.

I notice though, that when I move the controls from neutral to forward, that the engine shifts right away, but that the engine does not increase in rpms until I significantly advance the throttle lever.

Is there a way to get the engine throttle to be more sensitive to the initial movement of the throttle lever? I have to throw that thing very far forward to get the engine to increase in speed.

Thanks,

Frank

 

[jerryjerry05]

Re: How to adjust throttle cable engagement?

The original eccentric screw is what you need to help move the cam to the mark on the throttle advance.The straight screw will only let it rotate under pressure.
Along with that the connecting rod will screw in or out to align the mark to the roller.
Do the linc and sinc at the top of the Force forum.
As far as peak RPM,While the boat is in gear and going forward at WOT.Try to move it by hand.Check timing?
The size of the boat and load will affect the WOT.How bigs the boat and how many people do you have on board,how much stuff,coolers,kids,dogs etc ?

 

[Frank Acampora]

Re: How to adjust throttle cable engagement?

View attachment 136566

 

[NMShooter]

Re: How to adjust throttle cable engagement?

I don't attempt to put it in fast idle position for starting, as I am not sure if it works. It appears that my controller has a soft rubber cover over a button on the throttle lever, but when I push it in, it does not seem to allow the throttle to move either forward or backwards. I'll take a picture of it tomorrow and post to see if maybe I am operating it incorrectly.

 

[Frank Acampora]

Re: How to adjust throttle cable engagement?

You push in on the rubber covered button and hold it. While holding it, you squeeze the red lever on the bottom of the palm handle and advance the control handle forward. The red lever is a neutral safety lock. It prevents you from accidentally hitting the control lever and putting the engine into gear.

 

[NMShooter]

Re: How to adjust throttle cable engagement?

Thanks... I'll give that a try today.

I need to re-evaluate my desire to adjust the sensitivity of the throttle to the throttle lever position. It appears that there is not enough range in the throttle linkage to allow the carbs to go from fully closed to near fully open. However, if the timing tree is going from idle to fully advanced, this is probably not a problem with the throttle lever control. So maybe I am barking up the wrong tree.

I received the new cam roller shaft and will install that later today and see if I gain any range of motion.

Thanks for the help!

 

[jerryjerry05]

Re: How to adjust throttle cable engagement?

The stock equipment on your boat should be sufficient to advance the motor to WOT.If it's not then you need to reset it.
You need to make sure the cables are connected right.
Not too far on one end or the other.
Then when the throttle is in neutral,it should have just a bit of strech to make it come back to the stop.
Timing tree??
Towershaft is used for setting idle only.
Timing is changed by the shaft and nuts on the trigger arm.

 

[NMShooter]

Re: How to adjust throttle cable engagement?

Jerry, here is the issue.

The throttle cam currently does not contact the eccentric roller, because the roller shaft is bent. I suspect that this is a chronic problem and happens when people ram the throttle forward abruptly. I received a new roller shaft which is perfectly straight, but I have not installed it yet. Too windy today.

I need to find a way that will allow me to have the butterflies in the carbs completely closed at idle, and close to completely open at full throttle. Right now I have it so that they are completely closed at idle, which allows for an easy start. However, this arrangement does not allow them to open fully at full throttle.

Initially I thought that my throttle cable was not providing enough range of motion to allow me to fully open the carbs. But then i realized that the timing tree was swinging from the idle stop to the full throttle stop. It is not a problem of the cable.

Hopefully, the new roller shaft will remedy this problem and allow the cam to contact the roller with the carbs completely closed. I have to think that the linkage was designed to fully accommodate both ends of the throttle position, and that something is out of whack. I know that the roller shaft is bad, and I am hoping that the angle bracket on the butterfly shaft is not also bent out of position a bit.

The good news is that the engine is running great. I just have to get this final linkage problem worked through and I am hoping to have it squared away.

Thanks to all for the help.

 

[jerryjerry05]

Re: How to adjust throttle cable engagement?

Post a pic of the new screw.
The original is supposed to be offset so it can move the black barrel to make a connection.

 

[NMShooter]

Re: How to adjust throttle cable engagement?

You are having a real issue with this. Maybe this will help.

The center line of the screw and the center line of the shaft are offset from one another. That runout is what creates the eccentricty.

However, those two center lines MUST be perfectly parallel to one another. Parallel, but offset. I'm afraid that I won't be able to break it down more than that.

Here... I have taken a picture of the new screw and laid a razor edge so that you can see that there is no angular deflection. The centerlines are perfectly parallel. The old screw was not. I was able to straighten the old screw somewhat, but not enough to my liking.

 

[jerryjerry05]

Re: How to adjust throttle cable engagement?

The way you said it before was the screw needed to be just like a regular screw.Straight.
I thought you were trying to use a straight screw in the linkage.
And I'm just trying to help.Now I see the screw I understand what your doing.
Hope this new screw helps.

 

[NMShooter]

Re: How to adjust throttle cable engagement?

No worries. Text is not the best way to relate geometric issues. Pictures help. I appreciate the attention to this problem!

 

[travislyle]

Re: How to adjust throttle cable engagement?

Hi guys, I've got an '89 force 125 that I got cheap off a guy that tried to re-deck his bay liner but quit after he demoed it and saw the extent of the work. It is now on my boat and running, but I am having trouble getting the throttle/shift linkages right and hoping you could help. My problem is that when the motor is in neutral i cannot get it to idle up on idle only. The control works fine, but back at the motor there is a mechanical lockout that blocks the ability to advance the idle. Is that supposed to be engaged while in neutral? When I shift the move the linkage into forward or reverse it raises or lowers a tab off my throttle linkage and the throttle will work. Is that tab supposed to be locked in neutral? I was thinking that it might be to keep me out of higher rpm ranges at idle and my throttle is just adjusted wrong? Please help!!