70hp johnson WOT

[bondsman2]

I have bought a 18 ft astro with a 70hp johnson (i know small motor for the boat). It runs good and gets on plane quickly but it only runs about 32mph max. My father in-law has a 17ft tracker with a 40hp johnson and it will go that fast. Is there any way I can get more speed out of it?

 

[bktheking]

Re: 70hp johnson WOT

Isn't an astro fibreglass and a tracker aluminum? What are the weights of the 2 boats, I suspect your astro weighs double the tracker, it's all power to weight ratio, stick a 200 on your boat, then you will fly.

 

[steelespike]

Re: 70hp johnson WOT

The astro is about 1,600 lbs and rated for 175 hp.the tracker could be as little as 600.
depending on the year and model.
If you get us the year and model of boat ,the prop size(usually on the barrel or under the prop nut)
the max speed and most important the rpm.We can tell if your setup is performing as it should.If you need a tach the tiny tach is reasonable and easy to install.

 

[bondsman2]

Re: 70hp johnson WOT

its a 1989 astro quickfire f/s rated up to 150hp. the motor max rpm is 5000-6000. the prop size is a 13