1987 Ford Truck

check your starter relay for keeping the power going through it.

Finally solved this. After replacing the relay 3 times, checking the switch to make sure power was being turned on and off to the relay, cleaning all the connections, of course being sure the battery was fully charged. I finally removed the starter and took it to Kragens, since it had a lifetime warranty, I had them test it. They insisted it was good. I said to hell with it and bought another starter and relay anyway. Went home and installed them. The truck starts perfectly now. My only guess is that there was something wrong with the old starter, causing it to draw too much power & weld the relay repeatedly. Kagens test seems to be, if it spins, it must be good. This is the second time I have replaced a starter they insisted was good. The first was on my daughter's Mustang. The starter would not stay engaged, but they insisted it was good.