Can a rotary partially sieze, causing it to turn over slow as if the battery were almost dead even when it wasnt??? If so, what usually causes this problem and how can it be rectified?

 

IF you run a motor low/out of oil and spin a bearing or chew one up, it'll cause it to rotate inconsistently and just sound sick in general.

Perhaps you should try another starter, I've seen a couple of times where a starter would turn the engine, but very slowly, even when it had good connenctions and plenty of power/amperage...another starter rectified the problem.

Maybe check your oil filter or oilpan oil supply for metal shavings, specifically those appearing brass. And try another battery, cleaned posts and terminals, clean starter connections and block ground and tighten securely, and if all that fails, try another starter.

 

I pulled my starter out and took one from a local junkyard.When I got nearly the same results, I pulled both starters and em teseted at autozone, they were both good. I put new battery terminals on the battery and tightened them. Oil looks good. Car was recently in a fire due to a PD leak. However, I put the fire out fast so only a few vacuum lines and hoses were affected. Already changed them all.

 

Have you load tested the battery? Might be falling to <10V under load, at which point the starter begins to groan...

 

Ah, will try thanks for input