Couple problems I'm hoping someone on here can assist me in resolving on my 1987 Saltare with the 454:

-When I launch the boat, I power it off the trailer (in reverse) where it sits running while the truck and trailer get parked. I come back to the boat, go to take off, and within seconds the overheat light comes on. It's done this every time I've launched the boat and I've been able to just increase my speed through the water and it cools back down, but this most recent time, I tried to cool it down with no luck. I ended up opening up the water intake line in the engine bay and blowing through the line that goes down to the impeller. I blew pretty hard and it felts as though something blew out, but it's hard to say. I then hooked it back up but it still would not draw water into the engine. So I opened the line up again and poured water in the line going to the engine and the line going down to the water. After hooking it up and speeding through the water again it finally began to draw water and cool the engine back down. Is it normal for it to overheat right after launching or is there something wrong? My best guess for what happened today is that the line got air-locked when I blew through the intake line. Is this possible? Do I need to look at replacing the impeller?

-The other problem I'm having is with the throttle/shifter lever. It takes a LOT of force to get it out of neutral, and it's sloppy feeling in between neutral and drive once I manage to get it out of neutral. Is there any way to adjust this? Do I need a new throttle shifter or is it more likely something in the transmission itself?