Engine Kill Cable Adjustment

[djousset]

My Yanmar 2gm20f engine kill switch (a pull knob/cable from the cockpit control panel) has becoming more difficult to return to “in” position, it springs back a bit. For now I simply return it to proper position at the lever on the engine block. The length of the cable housing shows nothing obvious. I’ve also played with the cable length at the engine arm fitting with no appreciable difference. Is there an adjustment I can make or does this cable need replacing?

[SY Harmony]

Have you tried lubing the cable?

[GordMay]

1. “Backlash” is the lost motion between the amount of movement put in (input end of the push-pull cable) and the amount of movement which occurs at the output end of the cable.
Some motion is generally lost in “take up” between the inner wire (core) of the cable and the outer casing (conduit). Backlash manifests itself as free play (slop) felt at the control handle.
With increased length and bends, cable efficiency is reduced, while breakaway and backlash rise.

2. Over time, cables stretch, and will need adjusting, to reduce the amount of free play.
If the free play is out of specification, there are two places where cable slack can be adjusted, by moving the nuts, on the threaded ends.
The first is at the input and the second is at the output. Generally, the in-line adjusters at the input are for fine tuning the free play, whereas the adjusters at the output end are generally for bigger changes.

[GordMay]

Originally Posted by SY Harmony

Have you tried lubing the cable?

Lubricate stop cables periodically to ensure good working order. Use a water proof grease to do so. This is done by loosening the locking screw in the barrel at the engine side of the cable.
Pulling the inside cable out at the panel, take a water proof grease and generously coat the cable and shank. When the cable is reinserted, make certain the cable is pushed all the way in and the shut down arm is in the complete run position before locking the barrel screw back up.
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[SailingHarmonie]

Certainly lubricating a cable is a great idea, and it can help.

But in many cases for the amount of work you have to do to disassemble, lubricate, and reassemble, it can be more cost effective to just get a new one for $50-80. Depends on the condition of the existing cable, the complexity of the cable run, length, and labor rate involved. And the relative availability of cash vs. time.

[parkstone bay]

Technically - this isn't a "Kill Cable". (A kill cord/cable is a cut-off fitted to petrol/gasoline outboards to stop the engine in the event of the driver parting company with the boat. In this case, we are talking about the Engine Stop control. End of pedantry!)
What is important is less what what's happening on the cockpit control panel, and more what is happening on the engine itself, specifically its stop lever.
What is needed is to check the throw of the engine stop lever, by accessing it, then note what the total travel is when the stop control is operated from the cockpit. THEN, disconnect the cable from the stop lever, and see what the total travel is without it. In particular, when the cockpit control is down/nearly down (i.e engine running), is the cable holding the stop lever slightly open, or not. If the lever is in fact as far back as it'll go, then it's clear that, regardless of what's happening upstairs, the stop function isn't being, even slightly, actuated: it'll make the engine difficult to start. Equally, you should then ensure that when the control knob is pulled to stop the engine, the stop lever is moved to its maximum travel.
Yes the issue is almost certainly a stretched control cable. Is it a big deal? Possibly, but probably not. Carry out the above tests to ensure that the engine stop lever is being operated over its maximum possible travel.