New prop questions...

[nitefreak]

I have a 1981 Rinker open bow with a 1981 mercury 80 hp. Spent the day on the lake and got in some shallow water and ruined the prop. Current prop was a solas 13x19 my boat was not hitting the recommended rpm's of 5000 - 5500. I was hitting 4500 - maybe 5000 if i was lucky and running about 35 mph. My question is should i put the same prop back on it (solas 13x19) or what would you all recommend i put back on it to get closer to the 5500 rpm's? The boat is a 15 footer shouldn't i be getting a little more speed ot of the 80 hp?

 

[Bob_VT]

Re: New prop questions...

Drop 2" in pitch to a 17" and your rpms will go up. Mercs like to run at higher rpms

 

[nitefreak]

Re: New prop questions...

So go with a 13x17 and i should be good? Will i get more speed as well do you think?

 

[SparkieBoat]

Re: New prop questions...

I would think a 80 on a 15 boat would do around 40..if you could post exact WOT RPMs and exact GPS speed, it would help to figure out whats up.

 

[nitefreak]

Re: New prop questions...

WOT RPMs are 4500 and my GPS speed is 36 MPH.

 

[SparkieBoat]

Re: New prop questions...

you need to check spark and compression..then check the fuel pump/lines/connections..also can you raise the motor up more on the transom??? your motor should be able to spin that 19 pitch prop way faster..you would have to go down 5 pitches to get into the mid 5k rpm, that would be a 13-15 pitch prop, which is usually what you would use on a pontoon boat not a 15' speed boat. so I am pretty sure you are down some HP, maybe running on 3 cylinders or poor fuel supply or bad/clogged carbs..

 

[nitefreak]

Re: New prop questions...

The gentleman i bought the boat from had it in storage for 2 years before i got it. The motor fires right up and seems to run good to me,but i'm a new boat owner and don't know much about outboards.Im gonna have to take it in and have someone who knows more about outboards have a look at it...