Johnson 130 Prop change

[Shorebum]

I have a 2000 Johnson 130 with a 15x17 prop on it. The motor is pushing a 20 foot sea hunt that with 30 gal of gas and 450 pounds in people should weigh in just above 3000lbs. The boat jumps up real well, lots of torque, quick plane.
Motor will spin up to 5800 to 6000 RPMS with this load and go 40 +/- mph. I think that motor was rated for 5500 RPM, soo I would like to bring down RPMs and maybe get better gas mileage. This boat is fishing and traveling several miles at a time instead of pulling skiers. Can anyone guide me as to diameter and pitch to accomplish this. I do not want to buy a 21 and be overpitched or a 19 and be under etc. Thanks

 

[hwsiii]

Re: Johnson 130 Prop change

Shore, I show your motor is supposed to have a maximum WOT RPM of 6,000 RPM and a gear ratio of 2.25:1, please verify this.

Using the above gear ratio I find your prop slip is 7%, which is excellent and your gas mileage should be good.



H

 

[steelespike]

Re: Johnson 130 Prop change

H is right on; it is generally suggested that close to 6,000 rpm wot is best for todays fuels.
Your 130 should use about 13 gph(gallons per hour)at wot(wide open throttle).
If you want to optimize your cruising speed a prop change may be in order.
H may have a suggestion for a prop.Generally a 4 blade is thouight to improve low end performance and sometimes at no loss of top end.

 

[Shorebum]

Re: Johnson 130 Prop change

Thanks for replies. I was basing the 5500 RPM on advice of local mechanic who just put it out there. I am second owner so do not have an owners manual, couldn't find WOT in SELOC, and did not find on BRP website. This motor turns 6000 with current setup when planed out on flat water. Where did you find the rating of 6000 for WOT? I would probably not change anything if this prop is delivering WOT on the money.

 

[steelespike]

Re: Johnson 130 Prop change

6,000 is the is usiually suggested for these motors.And your surely well setup.
I would leave it as is as well. If your uncomfortable running at 6,000 just throttle back a little.You probably run at reduced throttle most of the time anyway.
If you add people/load the rpm will drop anyway.

 

[Dhadley]

Re: Johnson 130 Prop change

What's the complete model number of your motor?

 

[Shorebum]

Re: Johnson 130 Prop change

Dhadley
It is a j130vxsss