1977 DeVille hot start problem

[Koa]

Hi everyone,
my 77 Deville does not crank when hot. Battery good, wires checked, Can the starter motor be the cause? When cold it cranks like new.

[Roger Zimmermann]

I know that 70s cars, the cable from the positive pole going to the starter motor can oxidize under its protective isolator. Maybe its the same for your car.

[Dan LeBlanc]

Roger is pointing you in the right direction.  Take the cable off from the battery to the starter and check for resistance with a multimeter.  You should have no resistance.  Any resistance would indicate the cable is corroded internally.  Couple the resistance with a heat-soaked starter, and you're in the situation you describe now.

[TJ Hopland]

Another way to prove the issue is the cable is if you can access it reasonably and have clamp on clips is to set your volt meter up on volts DC with one wire at the battery and the other at the starter.   In theory you should read zero volts because all the power is going through the wire.   THe more volts you read there that means there is resistance somewhere between the leads.   If you are reading more than a volt or two during cranking you have cable issues. 

Don't forget about grounds too.   For testing take jumper cables and go from neg on the battery to something like the alternator or some other unpainted part of the engine.  If that helps then you know you have a ground issue.

[Koa]

Thank You guys for Your advise.
Noone suspects the starter motor??
All atention should be pointed to the wires?

[TJ Hopland]

My experience is a bad starter won't be that much different hot and cold.