need best size prop for 1998 115 johnson outboard

[moon rainbow]

i need to know whats the best pitch and diameter for a 1998 115 johnson outbord

 

[JB]

Re: need best size prop for 1998 115 johnson outboard

There is no such thing, Moonrainbow.<br /><br />"Best" props are matched to a rig. . .boat, engine and load. <br /><br />The best prop for your rig is the one that will allow the engine to reach the upper end of the operating range for that model engine with a normal load, but not exceed it.<br /><br />Good luck.

 

[walleyehed]

Re: need best size prop for 1998 115 johnson outboard

Give us some info as to boat size, type, your elevation above sea-level, etc., and I'm sure we can get ya close..

 

[moon rainbow]

Re: need best size prop for 1998 115 johnson outboard

sup boaters the boat is a 17 ft boston whaler weight of rig is about 2800 lbs thankes 4 info

 

[JB]

Re: need best size prop for 1998 115 johnson outboard

I have a BW Montauk 17, Moonrainbow. <br /><br />115hp is overpower (Max rating is 100hp), so watch out for the fuzz.<br /><br />Your boat weighs 950# dry. Add 300# for the engine and maybe 750# for other gear and passengers. Not over 2,000# on the water.<br /><br />I would start with a 21" prop with that engine and move up or down depending on the WOT rpm.<br /><br />Good luck.

 

[ob]

Re: need best size prop for 1998 115 johnson outboard

You didn't say which 17 ft. Boston Whaler you had moonrainbow.<br /><br />A 17 ft Dauntless weighs in at around 1500 lbs dry and has a max capacity of engine passengers and gear of around 1700 lbs.It tops out with a 130 hp engine.<br /><br />Then of course there's the 17 ft. outrage.1700 lbs.dry,1820 engine ,gear, and persons.150 hp. max rating.<br /><br />Let us know which Whaler you have and we can get more specific on the recommended prop application.<br /><br />If it is a Montauk ,Jb's got you covered.

 

[JB]

Re: need best size prop for 1998 115 johnson outboard

Thanks, OB. I assumed, which is a bad idea.<br /><br />You left out the original Outrage 17, which weighed 1150#. I think it was rated for around 130hp.<br /><br />OB's right, moonrainbow. We need model and year of your Whaler.

 

[moon rainbow]

Re: need best size prop for 1998 115 johnson outboard

thanks 4 the info the bw is a dauntless 17

 

[moon rainbow]

Re: need best size prop for 1998 115 johnson outboard

dauntlees 17 1995

 

[ob]

Re: need best size prop for 1998 115 johnson outboard

moonrainbow,I'd recommend starting with a 17" pitch three blade prop for your setup.Find a dealer or prop shop that will work with you and allow you to water test a couple and select the one that will allow your engine to run at 5500 to 5900 rpm at wide open throttle with a medium load.Since that boat tops out with a 130 hp engine and the minimum recommended hp is 90 hp ,I think the 17" should put you in the ballpark of the recommended rpm range.Only a water test can confirm your final selection is why I recommend finding a shop that will work with you through the testing process.<br /><br />Also,before prop selction, insure that the engine is mounted at the proper height with respect to the boats bottom hull surface.Lower unit anti-vetilation plate roughly even with boat bottom when trimmed parallel.This will minimize exhaust back pressure and drag.