new transmission with no neutral or reverse

I am hoping someone out there has some idea of what is going on with my 1977 ski Tique. I had a new velvet drive put in by a Nautique dealer 1 year ago. (not cheap). The problem I had before the new transmission was there was no neutral or reverse only forward.

After the new Transmission went it. It would run forward/neutral and reverse well until I had been on the water for a few hours then the boat would start to hesitate at high speeds. (I took it back to the dealer and they said they couldn't find a problem) The boat would kinda like having a hick-up at high speeds or under load, but it never sounded like the engine was having a problem. I had the boat winterized by a Nautique dealer (different, closer to home) last winter. I took the boat out yesterday for the first time this year. It was a beautiful day. I was on the water about 2 hours and it starts doing the hick-up thing. Then I found out I had lost neutral and reverse. I had only forward. When I put the throttle in reverse position it thinks it's in forward and there is no neutral. I looked at the engine. The level on the transmission fluid was 1/2 full and there was Transmission fluid in the bilge. Some please give me your thoughts on what's going on. I am so bummer out.

then again maybe there is a problem with the shifter and/or cable adjustment...if you are lucky

Charles, I would start by removing the trans cable from the shifter on the transmission itself and see if it still won't go into neutral and reverse. If it's still only forward then you can rule out the Morse controls and the trans cable.

Thats where my knowledge ends....

The linkage was the first thing I thought about (and I am pulling for you, I hope that is the answer), but the fluid in the bilge makes me think of something worse.