Mariner 100 Hp - 24' Pontoon

[mvance]

I have a 1988 Mariner 100 hp outboard and am pushing a 24' pontoon boat with a top deck on it. If I try to accelerate quickly the motor will rev very high but the boat will not speed up, as if the prop is cavitating (?). I can only accelerate slowly to get to top speed. I have no idea what prop pitch I have, as the boat and motor were bought used, separately. I suspect the prop does not have enough bite to push all the weight, and the pitch may be wrong. How can I tell what the proper pitch / propellor should be? I do not have a tachometer so I do not know what the rpm's are. Any suggestions would be greatly appreciated. Thank you!

 

[steelespike]

Re: Mariner 100 Hp - 24' Pontoon

You absolutely need a tach before you make any prop changes.A tinytach is reasonable,easy to install and will fit any similar motor without regard to stator poles.Speed is also very helpful.Perhaps a gps for a speed chack.
I have no idea what your gearv ratio is but A 12" pitch would be about right.Don't make any changes without a max rpm and speed test.
The wrong prop can lead to poor performance and economy at best and premature motor problems at worse.

 

[mvance]

Re: Mariner 100 Hp - 24' Pontoon

Thank you for the reply. I did some more research on this web site and see that much more information is required, as you note. I can easly get the max speed as I do have a gps. Do you have a link for the tachometer that you reference? I hope they are fairly easy to install. We replaced the deck and carpeting, and have also added an upper deck, and I really blew past my budget. I am not looking for top speed, as I realize it is a pontoon boat. I just want to make sure I have the most efficient prop for general travel around the lake. Thanks again!

 

[hwsiii]

Re: Mariner 100 Hp - 24' Pontoon

Here is the link http://www.tinytach.com/tinytach/index.php


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