TR4/4A Flat/dead spot on the starter?

[tdskip]

Hi guys - hope everyone's week is off to a good start.

Now the weather is (finally) cooling off a bit I am running around in the TR4a shaking her down for regular use. One recurring issue I am dealing with is that the starter has what appears to be a flat/dead spot. Here is what is going on:

1) Battery fully charged
2) Good grounds and solenoid connections
3) Used gear reduction starter
4) Sometimes she cranks to beat the band, starter easily cranks the engine over and she catches right away
5) Sometimes it will do a 1/2 crank and then bog to a point where the engine doesn't spin at all

#5 suggests to my eyes suggests I've got a bad starter and it needs to be pulled to be rebuilt.

What do you think? Yes/no/other ideas?

 

[poolboy]

When it bogs down, Tom, does the starter continue to spin, but the engine does not ?

 

[tdskip]

Hi Ken - neither the starter nor the engine spins at that point.

it is a fresh engine rebuild and still a bit tight but since it spins over easily at some points it seems like starter.

 

[TR3driver]

Could well be the starter. On the gear drive now in my TR3, I found that the armature bearings had died and were letting the armature rub on the pole pieces.

Another possibility might be the centrifugal advance mechanism. If it is sticking in the advanced position sometimes, the engine may be trying to start backwards and fighting the starter.

 

[tdskip]

Thanks for the responses guys.

Rebuild viable (would give to a professional) or better to replace you think?

 

[TR3driver]

I'd at least have it apart to see what the problem is. The bearings were easy to find at MMC, and the only special tool I used was a metric Allen wrench with a cheater bar. Fairly straightforward, but mark the relative position of the mounting flange before taking it loose. And don't lose the single bearing ball inside the output shaft. I just learned the other day that I apparently lost that ball, and that was why the starter wouldn't engage reliably.

Up to you on whether to rebuild or replace. Normally, I'd say a rebuild would be fine; but some years ago now I got 6 bad rebuilt alternators in a row! They all worked at first but failed within just a few weeks or months. Drove me crazy looking for what else was wrong, but I never did find anything and the last alternator lasted 3 or 4 years and was still working when my daughter traded the car in.