1997 mariner 60hp bigfoot rpm and prop questions

[trent0416]

hello all. i have a 1997 60hp 2 stroke bigfoot on my 20 foot pontoon, and a main issue is the rpm gauge does not work, thus not allowing me to monitor proper rpm, but this boat is a dog loaded or empty. first i need information on where my proper rpms should be for this motor, and is there any specific recommendation for prop diameter and pitch as well? i know this boat will not be fast by any means, but i just want it at max performance for what i have. i am lucky to get 10-12 mph out of this thing and it makes me wonder if my prop is too big for this. it currently has a 12 pitch, and once i get my gauge corrected i have a feeling my rpms are gonna be very low. also will there be any benefit by investing in a hydro-foil? any information here would be much appreciated. just looking to get the best prop option to maximize my rpm level for this application. been reading alot of folks saying a 9 pitch should be optimal for this setup, but looking for opinions. thanks so much everyone

Trent

 

[carholme]

Re: 1997 mariner 60hp bigfoot rpm and prop questions

what is your engine s/n?

Gerry

 

[slumberlost]

Re: 1997 mariner 60hp bigfoot rpm and prop questions

I have a 2008 60 hp bigfoot. I found that the former owner of the 20 FT. pontoonboat it is on had probably hit a rock and changed the prop to a 45 - 13 pitch before selling. The tilt won't stay up either. Even after Mercury supplied 4 new coils the rpms ran only at 4300 rpm. I have found a black max 14 - 10 pitch made for pontoon boats through Mercury. It's about $215. It should increase the rpms to 5000 where is just where it should be. Naturaly this will change under different circumstances.

 

[oldman570]

Re: 1997 mariner 60hp bigfoot rpm and prop questions

It would be best to get the tack working first or buy one of the tiny tachs to see just how many RPM the motor is turning. Then go from there on getting the prop that will let you get the most out of the motor without lugging the motor. Solas, Michigan Wheel are just some other prop manufactures that make props to fit the motor and are a lot less than the one you are looking at. I would think that a 10 3/8"X13P should get the performance your looking for. A lot depends on the weight of pontoon with all the extras and needs to be taken into consideration. Piranha Props are another good composite prop that I use. JMO
Oldman570