Top End Speed
Posted April 23 2012 - 05:13 PM
Posted April 23 2012 - 05:54 PM
The purpose of the jackplate is to RAISE the motor to decrease drag.
If your prop is in good shape, the 25" pitch should be the correct one.
If your motor is performing as it should, you should get about 70mph WOT
Posted April 23 2012 - 07:19 PM
The first is the fact the rpm is the same at both speeds. If that is true, I would have to quetion the tach.
Next, 5,100 rpm is way two low. With you and your normal load, you should have it proped to turn 5,800 to 6,100 rpm.
I would think a 23" would be closer to the right pitch, but until you can be sure of the tach readings, there's not much you can do with setup.
I've not had any dealing with the Xtreme but the 19' Stratos normally only runs in the upper 60's with a 200 and average load.
I would set my prop at 4 1/2" below the pad and then start adjusting up from their 1/4" at the time. However, like I said, you have to be sure of the tach first.
Something else I would do is a compression test on the engine.
Posted April 23 2012 - 07:20 PM
Also...I could be mistaken but I think you could still squeeze a few RPM out which would mean a prop change, however, I would wait until after you raise the motor to see what that does first.
Posted April 23 2012 - 08:24 PM
Looking for a little help. I have a 2000 Stratos 19SS Extreme with a Johnson 200. It has a 4 blade Renegade Bass prop 13 1/2 x 25. Loaded for tournament fishing. When planed out with just myself in the boat it will run approx. 56 mph at 5100 rpm. When my tournament partner goes with me it will only run about 43 mph at 5100 rpm. Guessing approx. 250 lbs. extra. I have the motor set as low as it can go without hitting the fiberglass when tilted up, using a manual jackplate. Any ideas to what might be the issue? Don't know if changing the prop is fix for this issue. Any help is greatly appreciated.
You don't want the motor as low as it can go. You want the opposite.
Posted April 24 2012 - 11:08 AM
Posted April 29 2012 - 07:23 AM
Posted April 29 2012 - 08:13 AM
When you had the motor dropped all the way down, what was the prop height? I have a BassCat Sabre 18'4" with a 150 Merc and 24 pitch Trophy prop. When I got it the prop was 3" below the pad and I would lose water pressure at WOT (Wide Open Throttle) 6300rpms. I dropped the motor in 1/4" steps until I got a steady 15Psi water pressure. Now my RPMs are still to high (6200) for my liking and I am going to try a few props in the 25 pitch range as long as it does not affect my holeshot.
By the way I am getting 60mph with 2 big guys and tourny gear at 5900 rpms which is not WOT for me, The one time a spun it all the way out (6200+) it was just me and all my gear and I reached 71 one dash and the one time I could look at handheld gps in my lap it was reading 68.2.
If you have a boat shop around ask if you can try out a few props. It could make a huge difference. Going from a 25p to a 24p prop in theory will give you 200 more rpms if it is the same style prop. If 5100 is your current WOT I would be looking at 23p props to get you into the 5500-5600 rpm range. Going from 4 blade to 3 blade can get some people more speed. Look at the tag on the transom mount of your motor, it should say what max rpm is.
BTW I rarely go over 50 in my boat .
Good luck and stay safe.
Posted April 29 2012 - 08:43 AM
Definitely need to verify or replace the tach.
Posted May 01 2012 - 06:44 PM
Posted May 01 2012 - 09:14 PM
Posted May 02 2012 - 06:08 PM
Regarding your boat, if the motor checks out, and nothing can be done about the hull except for repair, try to remove any extra gear that you don't normally use. Keep one live well dry if not in use. A couple of hundred pounds here and there can really affect your speed.
For example, when I bought my used 1987 Ranger 373 I told you about above, was completely stripped(no trolling motor or extra batteries, or gear) just the motor, 5 gallons of gas, and me, ran 68 MPH at 6400 RPM.
Once I loaded it down, now it runs 57-60 at 5800 RPM.
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