I have a 35hp 1976 Johnson. I bought it to put on my catfish boat. Let me sort of tell you the history. When I got it it was set up for controls. But I wanted a tiller motor. So I was able to make the change to a tiller off a 25hp motor. I think the tiller it a little short and would like to find a longer one if possible. It was a short shaft and I had to find an extension kit foir it. I was able to do that and it is now a long shaft motor. When I tried the crank it the motor cranked up as soon as I hit the switch. So I thought it was going to work out great. I replaced the water pump while I had it apart just so I would know it was ok. I tested it out and it pumped water out really good. Memorial day weekend we loaded up and went to the river. A bunch of friends and their boats and me and mine. Here I was with a deep wide flatbottom and a 35hp motor and it just didn't seem to have much speed. My GPS said it was going about 19mph. A friend and his 20hp went faster. I changed out the spark plugs to hotter plugs. That didnt work. Then it just died on my as we were heading out to run our lines. When I got back I checked it. No compression. I took the head apart. Blown head gasket. So I got to wondering if that might have been causing it to lose power. I put on a new head gasket. Took it out to a small lake to test it. After a couple passes across the lake, still at only about 20mph it quit. Blown head gasket. Oh, I forgot I had checked the compression after I had changed to the new gasket it was getting around 125 on each cylinder. I have a new gasket and will change that out again. But I know that isn't my problem. ANY IDEAS? I know its a long post. Just trying to fill in gaps.