Hard to start when engine is cold

[JWJ]

I've run into a recurring situation with my '85 300TD. It's hard to start when the engine is cold. The outside temperature does not appear to make a difference. When the engine is warm there is no problem.

If I pump the fuel primer pump about 50 times the car will eventually start when cold.

I've performed a valve adjustment, replaced the fuel filters, and verified the battery but this doesn't appear to have helped. There is nothing leaking onto the ground.

Any suggustions as to the problem?