Need help with a prop for my Mercury

Discussion in 'Bubba's Outboards' started by Raven Blayde, Aug 5, 2009.

  1. Raven Blayde

    Raven Blayde New Member

    Messages:
    320
    State:
    Kentucky
    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?
     
  2. bedbug jr

    bedbug jr New Member

    Messages:
    1,084
    State:
    Missouri
    Take it to your local dealer and let tell them your problem and they'll get you headed in the right direction. Much cheaper than trial and error. Stay safe and good fishing!!!:wink:
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    First off get a tach and add it to you instruments. It doesn't matter where the hub is spun on the prop or not the tach reads the engine rpm's from the recetfier not from the prop. I would have started with a 14 or 15 pitch and not a 17 as the other guys suggested. All merc props in the older field are black.
    You can have just about any prop rehubbed to fit any motor.
    Send this guy an e-mail and he is very helpful I have done business with him on several occasions http://danspropshop.com/index.php

    As for the motor taking so long to run right father out then that is most likely plug coil or fuel related. What type of plugs are you running and how long has this motor sat without useing.
     
  4. Raven Blayde

    Raven Blayde New Member

    Messages:
    320
    State:
    Kentucky
    Not sure what brand the plugs are (I'll have to go check). Even though the boat ran bad with the new prop in it, I fished with it all last year running that way (Was a pain). Last fall, I pulled all the sparkplugs and checked to make sure they were all firing and had none fouled out. Also rebuilt all 4 carbs and tried running it a few more trips before winter (ran the same way). The guy I bought the boat from said he ran it a few months before I got it and it ran okay.