changing engines??-which prop??

[nottleybill]

I have a 16' bass tracker. I am thinking about changing engines from my 1982 40hp merc to a 50hp 4 cly. 1987 merc. First any reason this would or would not be a good idea-please all comments welcome. Secondly if I change what size of prop should I run to stay within proper rpm range???

 

[AMD Rules]

Re: changing engines??-which prop??

Assuming that 50 hp is within your maximum rating for the hull (which it should be), it sounds like a good idea.

In regards to your prop sizing, it depends on a variety of factors includign the weight, size, hull geometry of the boat etc..

There is prop selectors online that can help you estimate the most suitable prop. They key is to make sure that at wide open throttle the motor is at its maximum rpms. This makes sure that at lower speeds, the motor is not lugging and potentially damaging itself.

This type of question is better suited for the prop forum, located here:

Prop Questions and Topics

 

[nottleybill]

Re: changing engines??-which prop??

does anyone know the weight difference between the 2 cly 40 hp and the 4cly 50 hp ?

 

[AMD Rules]

Re: changing engines??-which prop??

They didn't make a 50hp 4cyl in '87...but they did make a 45hp 4cyl Classic that year.

NADA Estimates:

1982 40 2cyl : 155lb dry weight (without power trim)

1987 50 3cyl: 185lb dry weight (with power trim)

1987 45 4cyl: 175lb dry weight (with power trim)

 

[nottleybill]

Re: changing engines??-which prop??

thanks for the weights- you are right it is a classic 50 and the front says 45hp but the guy at mercury customer service said it was really a 50 hp. sounds weird doesn't it?

They didn't make a 50hp 4cyl in '87...but they did make a 45hp 4cyl Classic that year.

NADA Estimates:

1982 40 2cyl : 155lb dry weight (without power trim)

1987 50 3cyl: 185lb dry weight (with power trim)

1987 45 4cyl: 175lb dry weight (with power trim)