Prop recommendations for 83 Johnson 235

[willienelsonjr]

I just bought an older boat and am wondering what prop you all suggest I run.

it is a 1980 19ft Intruder runabout, open bow, with a 1983 Johnson 235. It currently has a 15x17 prop, 3 blade. The boat is pretty heavy, seems like i saw a tag saying 3500lbs before motor (??). it tops out about 38-40mph now, at 5200 rpm, but seems like it should have more given the motor size. i am trimming it as i go.

I live in Fort Collins, and run in altitude, usually at 5500-8500 ft above sea level.

the guy i bought it from said it had a 21 on it, but he put on the 17.

what do you recommend?

thanks in advance.

 

[tashasdaddy]

Re: Prop recommendations for 83 Johnson 235

above 5000ft, you need to change the high speed jets. that's the reason for the reduction in prop. go to nada boats, look up your boat, there you will find the dry weight out of the factory, add the motor wt can be found there also. add and accessories, and gas, trailer wt. have the package weight at a public scale. this will determine if you are carrying any extra weight. see the boat is almost 28 years old, it is not uncommon for the foam floatation to absorb some water.

 

[willienelsonjr]

Re: Prop recommendations for 83 Johnson 235

the boat was out of the water for years, so i am hoping it is not the water weight. it is very dry here, so things dont really stay wet.

what jets should i get? and then what prop? can i find instructions in a SELOC manual?
i ran it this week at lake granby, 8300 elevation, and could barely muster over 30mph, at/around 5000 rpm.
it runs great, just seems to not have any top end. its gotta have more if i get jets and prop right, right? i have the largest outboard on the lake, but not much to show for it.

 

[willienelsonjr]

Re: Prop recommendations for 83 Johnson 235

also, i normally run it in Fort Collins, with an elevation around 5500 ft.