prop size for 1995 johnson 115

[grandinlake]

I have a 17 foot Pro-line with a 1995 Johnson 115 on it. The hole shot is terrible(loaded with gear and two people-other person has to move to the front of the boat. Im topping out at 37mph. I will be happy to reduce that for a better hole shot. I don't know what prop I have on now and I don't know what size I need. Any help would be great!

 

[zzzzz]

Re: prop size for 1995 johnson 115

remove the prop you have now and get us any numbers that you find...check the face of the hub towards motor

 

[Dhadley]

Re: prop size for 1995 johnson 115

We also need to know the top rpms with the average load. Whatever that load is.<br /><br />Good luck!

 

[grandinlake]

Re: prop size for 1995 johnson 115

That is also part of my problem. I'm not sure what the WOT RPM'S should be. When I bought the boat(used), I didn't realize that half of my owner's manual(the English version!) was missing. My bro-in-law fooled with the carb, but the RPM's were way high -- around 6000. Total weight of the boat, with gear, is anywhere between 2500 and 3000 I would guess.

 

[Bradster941]

Re: prop size for 1995 johnson 115

Hi grandinlake...<br />I have the same boat with a OMC seadrive. My 115 sits back behind the boat a couple of feet. I have no problem getting the hole shot with a couple people on board though my top end is 32 to 34 mph at around 5500 rpm. trimmed out.<br />My prop is a 13” with a 15 pitch aluminum. <br /> Also, with this configuration, you should be able to step up on and hold plane at 4000 rpm, and cruise economically at 42k to 44k which puts me at 26 to 28 mph..<br /> <br />Hope this helps.<br /><br />Bradster

 

[Bradster941]

Re: prop size for 1995 johnson 115

Ps. WOT should be close to 5500 rpm

 

[grandinlake]

Re: prop size for 1995 johnson 115

I appreciate it Bradster. I'll probably pull my prop and check to see what I have going on there and adjust if I have to. I knew my WOT RPM's were high, so I'll have to get it out on the water and adjust. Thanks

 

[Bradster941]

Re: prop size for 1995 johnson 115

Also, the pitch and size on mine is stamped on the outlet side of the prop at the hub. Look there first. (clean carbon away /w windex, wd-40, etc. )<br />If you have an aluninum prop that is close on pitch, you can send it out for recon and have them change the pitch. That will save you buying a new prop..<br />My guess is that you don't have enough pitch or your prop is worn down from its original size thus the high rpms and slow out of the hole. ( Its cavatating under high load ).<br /> If it is a stainless prop and close on size, have the recon place tip the blades. This is a slight forward curve on the tip of the blades that gives a little more bite into the water column and holds the water in place for the blade to do the work instead of allowing the water to slide off the end of the blade before force, ( work ) in achieved..<br /> Many boat dealers/repair shops will let you borrow props if they have them in stock for testing.<br />Good luck..<br />

 

[Dhadley]

Re: prop size for 1995 johnson 115

Your target rpm (with an average load) is 5800-5900 so if youre "around 6000" youre pretty close. If youre at 6000 with a light load it should be right on. <br /><br />However, at 6000 youre holeshot should be great. Describe what it is you dont like. Is it ventalating? (Just reving and not going anywhere) Or does it just kind of bog? (No rpm's - no forward bite)<br /><br />Good luck!

 

[grandinlake]

Re: prop size for 1995 johnson 115

its more or less bogging...like pulling a skier with too little power.

 

[Dhadley]

Re: prop size for 1995 johnson 115

Assuming the motor is running on all four lets check the tach setting first. Make sure its on position 6.<br /><br />Silly question so forgive me - you do take off with the trim all the way in (down) - correct?<br /><br />Let us know about the tach. Good luck!