Warm cables mean high current. This could be the result of a tight engine, worn-out starter, or inadequate gauge battery cables. If the battery cables were changed (even 18 years ago), they are most likely 4 gauge 12v cables. You should have a minimum 2 gauge cable, and 0 or 00 (1/0 or 2/0) gauge is even better (both positive and ground cables).
You will need these cables eventually, so replacing them is not a waste (about @$25). If the new cables get warm and/or the starter continues to be weak, then get a starter ($100-$150)
Good luck - let us know what you do and what happens.
Tim
PS: Here is a fellow who sells starter and genenerator rebuild kits; he also rebuilds them:
WEITZEL'S D.C. ELECTRIC
516 US Highway 250 South
Norwalk, OH 44857
419-668-2844
866-840-2844
[email protected]If you send off your starter for a rebuild, use a Priority Mail flat-rate box. Costs about $8 to ship up to 70 lbs anywhere in continental USA.