Thanks everybody for your detailed information. It will take me awhile to get dug into this problem, and because of it's age I may do extra to keep the motor in as good condition as possible. I run the dozer several times a year, and it doesn't smoke or miss when running. When I start it I usually turn the fuel on 5-10 seconds before I turn the compression on, it seems to start better that way.I have a parts engine that is near the end of the run, 5000 serial number. I'm thinking of robbing the transfer pump off of. The serial number on my dozer is 155, so it's an early one.

bringing this up for reference as i am having same problem. with fuel in engine oil

I finally got to work on the D65R. Took the injection pump off and replaced the O ring. It was suggested that I replace the back one in the pump. The parts book showed the same part number for the seal, but it must be wrong, because the plug was hard getting in and the casting broke on the pump when bolting the back on the pump. Luckily I had a parts motor to rob the pump off of and left the back O ring alone. Cat said the gaskets for the pump were not available. It's running great now, and no fuel in oil yet.. I was having a problem with the pony pinion slow kicking out when the big motor started, and discovered there was a grease zerc I have been missing. It's working great now. Thank You for all your help, I don't think I would have thought of that O ring by myself, but now I know where they are located. I already took the O ring off in the picture.