couple questions

[HEADWAVE@xxxx]

greetings all. finally had first spring run in the E today. great to be out. 
i have two questions, hope someone out there has some guidance.
temperature gauge - always shows temp fine on first start of car. after car 
is hot, on subsequent starts, the gauge always goes to null and stays there. 
if car has time to cool down, gauge works fine. just the sending unit? or 
should i be checking something else -- all other gauges work regardless of 
time or temp.

starter-rebuilt, installed last year or maybe year before. always cranks 
great when engine is cold. when engine is hot, sometimes won't crank on first 
turn of key, and when it does on second or third try (usually second), it 
seems to bind and then crank slow. do i need to replace again, or is there 
something else that might be doing this.
any ideas appreciated.

and thanks.

David Rust