New to me 1973 Johnson 50 model 50ES73R with Johnson Tilt & Trim; two tilt cylinders with reservoir on the aft starboard side.<br /><br /> The tilt would not go up full stroke so I drained the fluid by removing two lower aft facing plugs and the starboard side fill plug while the motor was part way up on the travel catch. The fluid was red and foamy, and I refilled to the bottom of the fill plug with type F ATF after replacing the lower plugs. I ran the tilt up as far as it would lift and added more type F until it went up full stroke. I then ran it down with the fill plug still out and foamy fluid was expelled from the fill opening. I ran it up and down a few times and refilled with the motor down and replaced the fill plug. It tilts enough for the travel position but still only about half of the cylinders full travel.<br /><br /> Questions: Should the tilt-trim be filled with the motor up or down? If I fill with the motor up do I risk building pressure and blowing something when it is lowered? Would 30W motor oil be less foamy than the ATF? Which fluid is recommended for a 1973?<br /><br /> I also have idle questions as it seems to run fast in neutral but stall when first put in gear in the water or idling in gear in the water, but later for that. Thanks
