The key is to replace the frayed or worn starter rope before the rope snaps, replacing a rope that has already broken and the spring unwound is a job which you should take to a professional.

Starter ropes are wound around a drum which is attached to a strong spring. Always exercise caution.

Inspecting the rope is part of any routine servicing inspection, do not pay lip service to this, the picture below will show you why. At ANY signs of fraying or wear, replace the rope, it’s cheap as chips to buy.

To inspect the rope, don’t just take a look with it pulled out fully, remove the starter assembly and turn it upside down then take a look at the full length of the rope paying particular attention to both ends as that is where the rope is most likely to fail.

This one is for  Yamaha 4HP 2 stroke, the Mariner/Mercury 4HP 2 stroke is similar in how the rope needs to be replaced.

In the picture below, the rope is fully exposed after removing the starter and the arrow is pointing to some pretty bad fraying real close to the drum end of the rope which would not be visible if the starter had not been removed to check the rope.

 

The easiest way to do it is, grab yourself a few small G clamps, remove the starter assembly and pull out the rope fully, clamp the drum to the starter case with the G clamps so in effect the rope is fully out and the starter is locked, the picture below shows exactly that.

 

I’ve just pulled the rope out from the drum end to better show the fraying.

At this point you can simply cut the rope and remove it.

Take a new rope that is the correct length and diameter as per the servicing manual for your engine (If you don’t have a service manual replicate the sizes of the rope you are removing).

Melt both ends of the rope to make sure they don’t fray and also squeeze up the end a little to reduce the diameter and make it easier to thread through the drum and handle.

Thread the rope from outside the starter assembly back through the starter assembly and through the drum’.

And tie a simple overhand knot in the end

Snug the drum tag end of the rope into the retainer (Blue arrow) and tie a simple loop knot into the handle end of the rope outside of the starter assembly (Yellow arrow) and you should end up with something like this.

All you have to do then is thread the un-knotted end of the rope through the starter handle and tie off the end with a double overhand knot.

Undo the loop you tied above, lock the drum to the starter assembly with your finger and thumb like the picture 2 above, carefully remove the G clamps and allow the drum to unwind under the tension of the spring, make sure you keep this controlled.

Then check if it works OK and refit the starter assembly to the engine.

Inspecting the rope regularly and thoroughly is vitally important, don’t forget that to replace a frayed or worn starter rope is easy enough, if you leave it and it breaks not only will you be stuck and unable to start your engine unless you have few tools but also the job will be much more expensive.