I have removed the engine and transmission because of a blown freeze plug between the engine and transmission. I figured it would be easier because I am replacing all of them. I need the remove the IP to get to the freeze plug right behind it. There is just not enough room between the pump and the block to do it right. I will only have the pump off just long enough to replace the plug and put it right back in. Is there any way to do this without going into a big deal and special tools to re-time the pump. I am not familiar with this type of pump. My international engine's pump will only go on one way and as long as you mark the outer ring, everything is good. From what I have read this thing has a splined coupler. The engine runs great and I don't want to change anything. I just want to take it off and put it right back on.
Any help will be greatly appreciated.
Thanks,
Rodney

Put a dimple on the block on on the pump flange.

http://www.pauldrayton.com/uploadfiles/merc/Service/W123/w123CD2/Program/Engine/617/07_1-200.pdf