Adjust throtle cable

[Cool It]

Good afternoon. I have a 1999 34ft formula pc with twin 7.4 mpi mercruisers Every season I seem to have the same problem and that is to run both engines at same rpms I have to push the starboard throtle up further than the port so the throtles are always seperate an fairly far apart my mechanic usually did some adjustment on starboard side while I am driving and the throtles come together nicely I don't have my mechanic this year and would like to try to do on my own any way anyone can explain how I can do this. It seems like it took him couple of minutes and it was done Oh the boat had bravo 3 but has seperate throtle and gear shifts similar to inboards appreciate any help Thx

 

[alldodge]

A mechanic adjusted the cables and it was working correctly and now it's off? What happened to cause the issue?

 

[Cool It]

It's usually fine for most of season then it start get further apart towards end of season then needs to be adjusted again beginning of season don't know why but at this moment I just want to have both throttle together

 

[alldodge]

This shouldn't happen, there are solid stops and they should not move. There is a cable which goes direct from the throttle lever to the carb/throttle body/etc and is secured by a lock nut. If it moves there their is an issue.

Issues which can cause this, cable jacket is worn out and needs replacing, lock nut has come loose or even the motor needs repair. If your rpms stay together at idle and a slight rpm increase, then start separating the more the rpm increases. then I would check the status of the engine falling behind. It may be weak and getting close to a rebuild.

There are two adjustment areas, at the throttle control and at the motor. If one needs more throttle to achieve the same rpm it could be the motor. If both can go WOT and achieve the same rpm then maybe its the cable.

Adjustment, set at idle, take slack out of cable and make sure both throttle levers are in the same pivot holes. There should be no issue to check pivot holes, see no one ever moving them. At motor end adjust so jacket is secure and cable end slide easy into motor throttle control. That's it, if both motors produce the same power then there would only be very minor differences in amount of movement needed

 

[Fun Times]

Sort of sounds like your throttle cables are stretching out internally. You may need new cables.
http://www.boatinfo.no/lib/mercruise...er23.html#/128
https://www.scribd.com/doc/76275169/...-Newest-Manual

 

[Bondo]

At motor end adjust so jacket is secure and cable end slide easy into motor throttle control.

Ayuh,.... I agree with everything ya said in this thread, as usual Bob, But,.....

I always have put 1/2 turn resistance from the cable, against the idle stop screw on the carb,....

That way, with a worn cable jacket, ya won't get a wildly racin' motor at idle,....
Set it at 700 rpms, 'n it always returns to that at idle,....

 

[alldodge]

I always have put 1/2 turn resistance from the cable, against the idle stop screw on the carb,....

That way, with a worn cable jacket, ya won't get a wildly racin' motor at idle,....

Agree, very good point, I got to much into why an adjusted cable would go out again

 

[Bondo]

Ayuh,.... That is odd,...

 

[Cool It]

When I ran wot they both ran very close rpm I ran up and down a few times funny now when I went back to my cruising speed the levels are much closer together now with rpms about the same levers are not exactly together but much closer and not bad don't know why they are better after running wot

 

[alldodge]

Maybe blowing the cobwebs out helped :noidea:

 

[Cool It]

That's what I'll go with lol I'll keep an eye on it and see how it holds up. Thx to all that responded to this question