Lately I've run across what are termed "starter booster relay kits", or
> words to that effect. These seem to be a relay, inserted in series with > the
> starter solenoid.
>
> Are they to boost a weak solenoid? Don't see how they could boost a
> dragging starter. If they are to boost a weak solenoid, how does this > happen? >
From what I just read it sounds like it is a temporary way to bypass the original solenoid relay - based on the assumtion that it is weak and made less effective by the heat.
Install a STBR, which connects the starter solenoid trigger wire to the battery terminal whenever you have the ignition key in the START position. a) get a headlight relay (Radio Shack 275-226); b) connect the ignition switch terminal coming out of the firewall to the headlight relay trigger point; c) mount the relay to the firewall, and ground the relay; d) connect the starter solenoid trigger connector to one of the switching contacts of the relay; e) connect the remaining switching contact to a fused 12 volt source (use a 10A fuse). (Refer to schematic diagram)