I am test running for the first time a 67 Johnson with a new impeller put in, I have started it up on a rough idle in a 5 gal can. I saw no water flowing out of the back pee hole, in the rear -about mid level- of the exhaust housing. I did check most of the tubing when I replaced the impeller and it seems clear. I could rev it up in gear or out of gear for a minute or so. but since I saw no water coming out I did not bother with keeping it going. The water in the can was up to the level of the cavitation plate. Is that high enough, or did it need to go higher in the bucket? (e.g.. say over the upper by-pass cover?) I am replacing the thermostat just as part of updating the maintenance and I saw little if any water in the thermostat housing. Quite dry.