I bought a 15ft 1970 "Supercraft" fiberglass boat a couple of years back with a Mercury 65hp 4 cylinder on the back of it. The motor started right up and ran great (out of the water). First thing I learned when it went in the water for the first time was that reverse didn't work. No big deal, don't need to go backwards too much anyway. 2nd thing I learned was that the prop was spinning very bad. It ran great at slow speeds, but the faster you tried going, the slower the boat moved (the rpm's would go through the roof as well). Here's where things get real crappy (as if they weren't anyway). I spent over a month trying to figure out what prop I needed for this motor. There were so many different styles, brands and "Pitches", I had no clue on what to get. The guys at another messageboard said that going by the part number I gave them from the old prop, it was incorrect for that motor. So, I made the next big mistake and threw the old prop away. From what I gathered from the people I talked to, I needed to know what the boat weighed and the rpm range it would be running. I had no clue at the time and still don't. The boat has no tach and if it did, it never ran right anyway to start with (having a spun prop). So, after a month of not getting anywhere, I just picked one and hoped for the best (yepp, another big mistake). I went with a 17' pitch prop with "Through Prop Exhaust" and replaceable inner hub. Soon as I took the new prop out of the box, I noticed right off the bat that it was HUGE compared to the prop that came off the motor before. The old prop was white also, where this prop is black like the rest of the motor. My thought was that the guys I talked to were right about the old prop being wrong. So, I went with the new one. Now, the boat dies as soon as you put it in gear. After several restarts and fighting with it, she will eventually start moving very slowely and stay running. After I get a 1/2 a mile or so up the river, it will finally start kicking in and I can open her up to full throttle. Then, the boat will level out and it will fly up the river like a rocket. Slow back down to a slow speed and it dies again. :embarassed: Now I don't know what to do. I have a brand new prop that isn't working and I'm afraid to buy another because I simply don't know what I'm doing when it comes to props. Any suggestions?