Many WWII jeep owners complain about "slow cranking" with their 6 volt starters. This is such a common problem that many folks just assume that 6 volt starters normally
crank slowly - but they don't!  Tired, worn-out 6 volt starting systems do crank slowly, but a 6 volt starting system in good condition works great.  

If your original 6volt system cranks slowly regardless of engine temperature, check the following items:

• Is your battery in good condition and fully charged? Duh!
  
• Are your battery cables of sufficient gauge (diameter) to work with a 6 volt system?  Joe Hall of Vintage Wiring of Maine recommends the original style 2 gauge copper wire with soldered-on connectors on both ends.  These are BIG FAT wires, not those puny plastic-coated ones from "Parts-R-Us" down the road.
  
• Is your engine block adequately grounded to the vehicle's frame using the original-style heavy-duty grounding strap?
• Are all of your cable and grounding strap connections clean, shiny and tight?
• Is your "step-on-it" starter switch in good condition?  These deteriorate over time and can cause slow cranking.
  
• Is your starter in good condition throughout? This includes the starter shaft bushing that is in the bell housing, too.
  
• How about your engine ignition timing?  If your ignition timing is set too far in advance it will cause your cranking system to labor.
• Is your engine properly broken-in?  A freshly rebuilt engine can be very "tight" and hard to crank until the break-in period has passed.
  

If you can answer "yes" to all of the above questions then your 6 volt starting system should be working just fine.  If any answer is "no" then you can expect a slow cranking starter with a warm or cold engine.

If you have a starting system that cranks well with a cool engine, but bogs down when the engine is hot, then the problem is probably worn-out starter bearings/bushings.  Bringing your starter to the rebuild shop will allow the technician to replace the bushing on the commutator end of the starter motor, and this alone will help temporarily, but on WWII jeeps there is a bushing in the bell housing of the jeep which will also needs to be replaced - not a simple task.

After 13,000 miles and 6 years of driving Sweetpea, the tell-tale signs of bad starter bushings ( poor cranking in hot-engine conditions) appeared.  I knew that the starter needed a rebuild and the bushing in the bell housing needed to be replaced.  It was a two-evening job (with the starter being out in the shop overnight) but not all that onerous after all,  and the results were outstanding.

(Note: Before you start ripping your jeep apart, be sure to purchase a new bushing and I would also recommend a new "step-on-it" starter switch.  Now is the time to replace the switch as it is very difficult to access the switch otherwise.  These items are available from Ron Fitzpatrick jeep Parts and may also be found locally)

  So, let's get started! You are going to need room to work so remove the right front wheel,  battery, air cleaner,  and right fender to gain access.  You don't need to disconnect the wires from the regulator, just set it on the empty battery tray.  You can also leave the fuel line connected - it's not in the way.

 

  With this stuff out of the way it is easy to remove the starter and send it off for a rebuild.

 

Now you can see and access the bushing way in there past the flywheel.  In the picture below, the bushing has already been driven out using an appropriately sized socket with an extension and a mallet.  (Yes, I know that "real" mechanics frown on using sockets as drivers, so what?  It works and so I do it.)  I have driven the bushing back and out of the bell housing.  This has pushed the plug out the back, too.  Be careful to save the plug, you'll need to reinstall it later.

Now you need a bushing driver to install the new bushing.  I made my own driver for a couple bucks using the items shown below...

 Assemble the1/2" bolt, nut and washer as shown and apply a single layer of masking tape to the threads to cushion the inner surface of the bushing and to keep the bushing in place. 

The tape makes for a very snug fit when the bushing is slid into place on the driver.  This prevents the bushing from falling off and possibly falling down into the bell housing - that would NOT be good!

Tap the new bushing in place using the hammer of your choice.

Now we need to get creative to re-install the plug that goes behind the bushing in the bell housing.  This plug is like a freeze plug, but only serves to keep dust and moisture off the bushing so it has no pressure against it once it is in place.  I put mine in by assembling a clamp affair using the items blow.  The cleaned-up plug is the item that  looks like a coin in the picture.  Yup, there's another socket serving as a "driver"!  Sorry to you purists, but I'm just a regular guy on a budget who needs to get the job done.

Again our trusty masking tape saves the day, this time by holding the socket in place for us as shown.

A scrap of wood bolted in place using the original starter mounting hole and bolt gives us a surface to clamp against.  I applied a tiny amount of black RTV on the plug and on the plug seat before driving the plug back into it's home.

After installing a brand-new "step-on-it" starter switch in position, I shined up ALL of my connections before re-assembling the cables. After the clean connections were re-assembled I gave them a coating of grease to help slow down corrosion. You can see my freshly rebuilt starter on the bench waiting to be installed.

Ah, now that's a thing of beauty!  Please notice the double clamp holding the battery cable in position next to the short starter-to-switch cable.  Also, look at the massive diameter of those 2-gauge cables!  That's the kind of wire you need to carry the amperage of a 6 volt starter system.

After reassembling the rest of the vehicle I can tell you that the new bushings and new starter switch have cured my sluggish "hot starts".  Sweetpea cranks briskly and effectively in all temperature conditions now ON 6 VOLTS.