Starter problems

I own a 1988 F350 5.8 Litre Windsor box truck, I have gone thriugh seven starters already and dont seem to know why? All electrical componenants are new and I have also tried some universal spacers, but nothing seems to help! Does anybody have an I dea why they keep binding/burning out so quickly?

Note: I have also looked at the flywheel teeth and everything seems good.


Thanks

Start by checking the battery, cables, all connections all the way to the starter, and make sure theyre clean and tight. Also check the ground connection on the block. Make sure youre getting full batt voltage to the starter, low voltage can cause one to get hotter than it should. Has the truck had exhaust put on it, and possibly a pipe is too close to the starter? Make sure the starter isnt staying engaged after the engine starts. I have seen bad , or improperly adjusted ignition switches cause the starter to engage while driving. The actuator in the column can break and sometimes cause this too. Make sure theyre giving you the correct starter for that application, and not just giving you the same part number, some 6 cyl starters may fit, but wont have the torque to do the job. After you put a new starter on, is it turning the engine freely, is the engine kicking back as if the timing was too high? Dont know what brand youre getting, but are they checking them when you take them back? You might want to switch brands, if everything else checks out ok. Just a few things to check. Good luck.