Guests - If You want access to member only forums on FM. You will gain access only when you Sign-in or Sign-Up on Fishing Minnesota.

It's easy - LOOK UPPER right menu.

Sign in to follow this  
Followers 0
polarsusd81

How to find the right prop...

4 posts in this topic

I have a Mariner 15 and one of the prop blades is missing crazy.gif. It is one of the Japanese built Mariners and I have the serial number from the motor, and found some markings on the prop itself. On the prop I found 9 1/4x12-3 which I know is the diameter x pitch - blades. I also found another marking that said 639 and then had a 9 under the 3. I have talked to a few places in town and everyone gives me a different story and I would like to get the right prop. It looks like I will have to order it online, but I want assurance it will fit if I place the order. Is there anyone out there that really knows the Japanese Mariners and can explain them to me?

Also, along with the prop question is another. For pitch, does a lower or higher number give you more top end speed? I would like to go somewhere in the middle. I have seen them in a range from 7 to 12 for 15hp motors.

Thanks much,

Tom

Share this post


Link to post
Share on other sites

Quote:

Also, along with the prop question is another. For pitch, does a lower or higher number give you more top end speed? I would like to go somewhere in the middle. I have seen them in a range from 7 to 12 for 15hp motors.


Higher pitch = more top end speed, but less hole shot

Share this post


Link to post
Share on other sites

Quote:

Quote:

Also, along with the prop question is another. For pitch, does a lower or higher number give you more top end speed? I would like to go somewhere in the middle. I have seen them in a range from 7 to 12 for 15hp motors.


Higher pitch = more top end speed, but less hole shot


Yes, but the prop pitch goes in conjunction with the size/weight of the boat.

Generally, it's done by monitoring engine RPM then changing prop pitch up or down until the engine runs within the full throttle RPM range recommended by the engine manufacturer. 1" pitch change translates to about 200 RPM change in the engine at WOT.

There is enough history behind this that a dealer should be able to tell you fairly accurately what pitch to select based on the size of the boat and "normal" loading.

Share this post


Link to post
Share on other sites

After doing a little bit more research, I think I am going to try to get a 9 1/4x9 prop. The 12 I have right now just doesn't allow the boat to get up on plane right now with me and my buddy plus the gear. With only me, it can do it but it is still struggling. I just think the old engine isn't what she once was.

Thanks for the help,

Tom

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  
Followers 0



  • Posts

    • knoppers
      that's the spot I would go also. I tried there once this year, not much luck, but I did mark many fish.
    • delcecchi
      I have a couple of those covers.  Not sure what they are good for.  
    • delcecchi
      Likely story.....   Uffda
    • Tyler Holm
    • PRO-V
      11 days passed and no updates??
    • Bryan P
      For all you pan fish lovers, check out this beautiful pumpkin seed I found guarding the bed while I was out bass fishing. Couldn't help but get some video of this beaut! Enjoy!    
    • Bryan P
      For all you pan fish lovers, check out this beautiful pumpkin seed I found guarding the bed while I was out bass fishing. Couldn't help but get some video of this beaut! Enjoy!    
    • leech~~
      My live well has an adjustable shut off valve in side for filling and running fresh water. If I don't turn it down to a tickle when I have fish in it, it will over flow into the boat once full because the pump is pumping faster then the overflow can keep up.  Not sure if you have one of them in yours?  I've even had a few big eyes flipping around in there hit the valve open more.
    • BobT
      I believe minnows are a class of fish that remain small throughout their lives. They are part of the food chain and because of their small size we take advantage of their position in the ecosystem and use them for bait. There are exceptions of course but, as an example, for the most part adult golden shiners will typically grow to about 3" - 5" long. Adult fathead minnows will be 2" - 3" long typically. 
    • Cliff Wagenbach
      If the hoses or hose connections are not leaking check : Live well intake connection, make sure that it is screwed on tight into the transom and that it is sealing. Could be live well splash over also if you are in rough water, but probably not with your type of leak. It may still be leaking rivets as they may not leak unless you put a lot of water inside of the boat. It does sound like you have a bad connection in one of your live well connections! Cliff