Trimmer Starter

I'm out there in the yard on Saturday afternoon, getting ready to trim the edges.  I pull on the String Trimmers cord, and pull it right out of the Trimmer.  Fork!  We'll its not the first time I have done this.  Actually its getting kinda routine.  My Homelite Versa Tool was manufactured in 2001, so its got a few miles...

The starter assembly is right next to the motor, under the shaft boom, so we'll have to take the Trimmer nearly all the way apart to get to the starter assembly.  The first thing to come off is the tool assembly, or the trimmer head.  It has a quick connector which is a clamp and a button.

There are other tool assemblies available for this this power module such as an edger and a blower.  Next we'll take the primary boom off the power module.  Here we'll need to disconnect the throttle cable and the electric shut off switch.  Then there are four screws the hold the boom onto the power module.

All of the screws on this Trimmer are T-25 Torx Screws.  I had to buy a set at the Cheap Tool Store, but in one instance the shaft of the driver was loo large, and I had to modify it.  To remove the throttle cable I needed to remove on of the cowling screws that has a bracket that holds the throttle cable.  Then the electric shutoff switch has a couple of quick disconnects.

Now we're down to the clutch.  This is where I had to modify the T-25 Torx driver shaft.  It was too large to go down into the clutch bellhousing.  To extract the clutch bellhousing you need to unscrew the screw inside of the bellhousing.  Also you need to secure the crankshaft so that you can unlock the bellhousing screw.  I take a screwdriver, ad insert it between the vanes on the flywheel, and wedge it in the cowling.  This allows you to torque the screw, without rotating the crankshaft.

Now we're down to the Centrifugal Clutch.  I had a little trouble here this time.  When I first reassembled the Trimmer the clutch wouldn't engage, and after a little troubleshooting I found the clutch plates we're rusty, and sticking to each other.

 I rectified this by sanding down with the clutch plates with course grit garnet paper.  I had tried to add some Lithium Grease to make sure they wouldn't stick, but that ultimately caused clutch slippage, so after I cleaned off the grease the clutch is working good again.  Now we can remove the cowling to get to the starter.

There are two pieces to the cowling, and the back comes off first with two screws.  Then the front has another three screws, and that is where the starter assembly is located.

The starter is a spring loaded return spool which actuates a pawl drive system.  This means that when you pull the string the pawls engage, and turn the shaft, but if the shaft is turning, then the pawls are disengaged by centrifugal force.  There is a plate which holds the sing loaded starter in place.

The starter pulley has a sprocket on it that catches the pawls on the flywheel, and spins the shaft when you pull the cord.  This pulley is now loose, and can unwind if you let it.  Also there is a coiled return spring under the starter pulley.  Be careful not to disturb the return spring.it will sproing all over the place.

Once the Starter Pulley is free we can remove the old cord and replace it with a new one.  Take note of the direction the cord is wound on the pulley and wind it back in the same direction.  The cord is held in place with a half hitch knot.  The cut end of the Nylon rope can be sealed, or terminated with a flame.  I usually take a lighter and melt the cut end of the Nylon rope.

After the Starter String is replaced then we'll reassemble in reverse order.  Once the Stater spring, pulley, and support plate are reinstalled, then we need to pretension the string, and install the pull handle.  When I rewound the Stater Pulley I used extra cord for this purpose.  Pull the cord out of the starter until there is a slight tension on the cord, then clamp the cord to prevent it from returning into the starter.

The we'll push the starter handle up to were the clamp is.  Make a half hitch knot to secure the starter handle.

Then we'll trim the Nylon cord, and terminate the cut end with a flame, like a pocket lighter.

Now the actual repair is completed, so now we can reassemble the string trimmer.  Here I am going to spend a little time cleaning the unit up before reassembly.  There is at least a couple years of krud built up on it since the last time I changed the starter cord.

The first thing to go back together is the cowling.  Three screws for the front, and another two in back.

Next the clutch plates go back on, no grease this time.  You don't have to torque these down.  The shaft spins counter-clockwise from this perspective.  The power of the motor will torque the clutch plates into place because the screw in right handed, screws down clockwise.

The clutch bellhousing is next, remember we need to lock the crankshaft when torquing the bellhousing screw.

Then we'll replace the transmission boom, which transmist the power from the motor to the tool assembly.

Reconnect the throttle cable, electric shutoff switch, and the tool assembly and I think we're good to go.

It ran the first time I pulled the cord.  This time without the clutch slippage problem.  I think we're back to String Trimmer homeostasis...