Resolved: 1963 75hp Hot Starter

[yorab]

Motor in signature. Motor has been recently rebuilt. I did not get around to replacing the wiring though. Before the rebuild, the starter seemed to work well. Never had a problem with the starter. A few days ago, I tried to run a compression test but I couldn't get through it because it seemed as though the battery was not strong enough to turn the starter for more than a very short while. I took the battery to get tested and it passed. The battery is 8 years old though so I bought another. I charged it completely as soon as I got home because I read somewhere that it can't hurt to do that. It was almost completely charged anyway. I also replaced the battery-to-junction box cables and cleaned all connections.

I tried the starter with the new battery today because I wanted to test for spark on each spark plug lead. I only bumped the starter for no more than 10 seconds at a time. The new battery seemed like it was having trouble turning the engine over. I could spin the flywheel relatively easily by hand, so I knew that there was nothing wrong with the engine internals. Then I felt the starter and it was pretty hot. I'm guessing that either the starter itself has a problem or the wiring to the starter has a problem.

During my rebuild, I replaced the brushes and cleaned the commutator with emery cloth. I also cleaned the inside of the starter to remove old carbon and crud. I tested the armature to make sure that it wasn't grounded as per the directions in the FSM. It checked out ok. I also checked to be sure that the hot lead wasn't grounded to the starter frame. It checked out.

There is obviously a problem somewhere. If a wire is bad, then I would think that the increased resistance would show up as a greater voltage drop across that wire. Is this the case? How should I go about logically finding my problem without replacing everything? I'll replace all of the wiring someday, but I've got a boatload of stuff to do without dealing with replacing the wiring (pun intended )

 

[boldtr]

Re: 1963 75hp Hot Starter

Re: 1963 75hp Hot Starter

If the starter is hot, then you are getting power to it. Here are things that come to mind:

1. Check the bushings on the top and bottom of the starter for wear. It could be binding. You can put one (1) drop of 3-in-one oil on each shaft: bottom and top just below gear to reduce friction. Do not use more than one drop...you don't want any oil in the starter. The oil will really reduce friction in the bushing.
2. Check the bushing for the bendix gear above the starter. The bushing is in the motor mount. Place one (1) drop of oil on the Bendix shaft and bendix bushing to reduce friction. DO NOT PLACE ANY LUBRICANT ON THE BENDIX GEAR ITSELF...just the bushing.
3. Disassemble the starter and check the resistance of each commutator contact to the shaft. Each contact (winding) should have a similar resistance value (e.g. not zero)

 

[yorab]

Re: 1963 75hp Hot Starter

Re: 1963 75hp Hot Starter

Thanks boldtr. I checked the bushings before reassembly and all good. I also put a drop of oil on them per the FSM manual. I believe that those areas are ok. I will check them again to be sure that no junk got caught in there during reassembly. Today, I will check to see if there is a voltage drop anywhere in the hot wire from the battery, through the soleniod, and on to the starter. I'm guessing that there should be little to no drop across those wires. If that checks out, then there must be something internal to the starter motor that is iffy. I will check the commutator as you suggested.

I'm not really following any kind of known troubleshooting guide to test the starter circuit. I'm just using my limited knowledge to come up with some checks. Am I going in the right direction?

 

[boldtr]

Re: 1963 75hp Hot Starter

Re: 1963 75hp Hot Starter

If you need to get a new starter, I would go with the Prestolite. That is what I have. You can pick them up used or new on ebay. Also, the same Prestolite starter was common for Harley during the same time period. If you search ebay, include Harley in your search. You can even get one in chrome!

 

[yorab]

Re: 1963 75hp Hot Starter

Re: 1963 75hp Hot Starter

I checked for voltage drops from the battery to solenoid, across the solenoid and from the solenoid to the starter. Max drop was 0.2 V. The guy at the alternator shop said that was okay. Next, I bypassed the solenoid and connected the starter directly to a fully charged and brand new battery. Still, the starter seemed to struggle to turn the flywheel. I took the starter off and inspected the innards. All seemed well. I wiped off the bushings and the corresponding armature jounals and put on another drop of 3-in-1 oil. The bushings were already clean and well lubed, but it couldn't hurt to clean and lube again. I also put a drop on the bendix bushing and shaft. I put it all back together and tried again. This time, the starter acted like a newly rebuilt starter. It had no problem turning the flywheel at a respectable speed.

I'm still not sure what was wrong, but it works fine now. I wish I could pinpoint the problem for my sake as well as for anybody else's sake who may be reading this. But I'll take it the way it is.