DD 6-71 Throttle Adjustment

[markpj23]

After many hours of routing new cables and installing new controls, I have discovered that one of the engines has a binding throttle. The condition was present before changing the cables, but I attributed it to the old cables.

The picture shows where the throttle cable attaches, and it is that throttle lever assembly where the problem lies.

As the throttle cable pulls to open the throttle, you can see the pivot arm move sideways as it moves aft. Like an eccentric bushing or something. When it reaches this point of sideways movement it gets hard to move. The result is that forcing the throttle through this arc of resistance will bring the engine from idle to full rpm almost immediately. To get to normal operating rpm I have to very carefully bump the throttle open using 2 hands on the control. Once at the rpm I want, the throttle does stay in position.

A quick phone call by a friend to a DD pro indicated that there is an adjustment for this. Have not been able to find it in my service manual.

Anyone have experience with this?

 

[Antares]

If the end fitting onthe cable is binding on the arm I would try mounting ii with the treaded boss to the outside or using a thicker spacer. That would angle the cable out a bit but usually is ok. This assumes the throttle does not bind with cable and fitting disconnected.

 

[markpj23]

The cables are fine. The binding occurs even with the cable disconnected. The issue lies within the bushing / cam / shaft of the throttle lever assembly that acts upon the governor.


Kinda hard for me to explain, but you can visibly see the throttle arm move sideways as the arm rotates through its motion.

 

[C lectric]

You may then have to consider pulling the pump to get the bushing repaired.
I would though also consider trying to realign the cable securement point so the push/pull is straight and inline with the arm movement. THe offside pull may have contributed to faster wear.

At least with DD the injection pump does not have to be timed. It is just a pump although variable displacement and pressure.

I am also going to suggest going to Boatdiesel and posing this problem to

Ronald Sparks

who is a DD expert and has talked/written many through DD problems, often quite extensively. Of course he is busy but he will reply if he can.

 

[Lepke]

The bearing is worn from the cable being improperly aligned. I think it's a bronze bushing that's easy to knock out and press a new one in. Also could be a problem with oil reaching the bushing.