I had the same problem with my 88 diesel but not quite as bad. If it was up to temp. it would not start for about 15 min. I discovered I had an exhause valve spring broke wich required me to send the head in the have new seats put in and had it planed. In addition to that I had the injectors rebuilt because the tips were worn out (my diesel shop warned me because they said if they rebuild the injectors those old bosch pumps may not create enough pressure for the injectors to operate correctly) I put it all back together and turned up the fuel on the pump to compensate for the tighter injectors and now it starts excellent wether it is hot or cold. I can not tell you exactly what solved my problem. I do know that it can get expensive to have the head done but if you have a good diesel shop near you they can test your injectors to see how bad they are. I had mine rebuilt for $15/injector which is relatively inexpensive for these old tractors.