Noticed a sudden slowdown in cranking during start on my 92. Battery is reading 12.6 volts, terminals tight and clean. Starter relay is fairly new. Does this mean starter is going? Is there an easy test? Starter is the original and I have 139,000 miles. Should I just replace the starter?

 

I would say with that many miles on it that it did pretty darn good, replacing it would probably be a good idea.
I would also check the cable from the solenoid to the starter, sometimes they tend to get cooked from the heat down there.
BTW - I have had solenoids last less than a week so don't let it's age be an indicator as to how good it might be. That's a pretty cheap thing to replace for piece of mind.

 

If you have a VAT tester, or a multimeter with an inductive pickup you can do a starter draw test and see if the starter windings are going bad. I would also check and see what the voltage drop is between the pos. batt. terminal and the pos. terminal on the starter. The cable corroded on my 1992 and caused a silmilar problem. It will also cause the starter to go bad because the starter is trying to spin the engine over with not enough voltage.

-Jon

 

Sounds to me like it could be two things. First, I think you are very lucky to have gotten that many miles out of your starter. I have a 93 f150 5.0 with 198000+ miles and I have had 4 or 5 starters (I forget). Anyways, it could be the starter. Another thing, however, that comes to mind is the fact that your timing may be off. It may not make sense to you or some, but if your timing is off, your engine will crank considerably slower, just like the battery was going bad. I would have a mechanic check the timing before buying a starter. With that many miles, the timing chain is bound to be stretched. This can cause the timing to be off. I had to change my timing set at around 150000 miles, so you arent far off. Hope this helps some how.