Replaced throttle cable, idle running at high RPMs

[Brian D]

The length of the throttle cable from my pedestal to the outboard was 13 feet. It needed to be replaced and the path it took looked like there was excessive cable. So I replaced it with an 11ft cable. Now the motor is running fast when in idle.

Here are the symptoms: When I start the motor and it warms up, the idle RPMs increase. If I wiggle the cable a little I can get the RPMs back to normal. But if I let go of the cable it climbs back up to a higher idle speed. When in gear, the RPMs drop to normal, but I think that is because there is now a load in contention.

I am sure all I need to do is adjust one end of the cable so the push or pull of the cable is equal. Otherwise it seems that maybe the cable is pushing the motor's throttle forward a bit causing the motor to idle at high RPMs. I don't think I should tamper with the idle adjustment screw though.

Any other thoughts before I head back down to the boat to make these adjustments?

 

[Ken Cross]

I think you got it. You may want to check for excess friction in the cable.

Ken

 

[NYSail]

When I replaced mine although there appeared to be excess it was so that the turns would not be so sharp angle for the internal cable. Also my throttle cable had a tensioner clamp on it to restrict the internal cable from moving.......

Greg

 

[agprice22]

Yeah, cable length can seem excessive, but it is so that the bends are long to allow free movement. Bends need a big radius, like 24”. You may have created undue friction by shortening the cable. If you did not change the idle, it does not follow that it would need changing after a cable change unless you changed it without realizing.
Also, did you lube the new cable, or did it come sealed and lubed? I have seen steering and throttle cable that came lubed and sealed in wrapping. I have seen some that required lube.

 

[Brian D]

I purchased the cable from Yamaha. It is a branded cable so I am not sure who made it. I guess you can say it is sudo-sealed, if that is possible. I did drop some 3in1 oil in the ends. The more I think about it the more I feel I should have gone with the original length of 13 feet. But the 11 foot was $56. So dang expansive. I will have to live with it.

I am waiting on one part for the controller and when I get it I will head back to the boat. I think I will adjust the cable connector at the motor. I will screw it in so it is a little shorter. The other possibility is to swap the shift cable (13 ft) with the throttle cable (11 feet). That should solve that. LOL

 

[agprice22]

I The other possibility is to swap the shift cable (13 ft) with the throttle cable (11 feet). That should solve that. LOL

Eeek! I think you just suggested it would be better to be stuck in gear than have high RPMs!!!

 

[Brian D]

No, the cable is long enough to change gears. The cable ends are adjustable so that one can make minor length changes. I doubt very seriously that the shift will be affected. Heck, only one way to find out, yes?

 

[agprice22]

If I recall correctly, I actually had the same motor as you, and I installed my own remote throttle. When I was routing the cable, the motor is about 3 direct feet from the throttle, but there was an offset that would require 2 sharp bends in about 12”. In order to not bend the cable too sharply, I had to order a cable long enough to have a wide loop, at least 2 feet in diameter, under the cockpit floor. It worked fine.
I loved that motor!

 

[Brian D]

So this project is also closed. I adjusted the length of the throttle cable and made minor adjustment to the idle screw. The motor is now purring instead of acting like it was on steroids. I will probably go back to a 13' cable later on. I thought I could save some money on a shorter cable but it looks like it was the wrong choice. Oh well. I do have a digital tachometer and will set the idle correctly later. But this is done.