hp question

[bo brown]

I'm new at all this jet boat stuff. Eager to learn though. bp you helped me last week with shoe angle question. I took my 17ft Rogers out yesterday. With a gps the boat only ran 62mph. I have a 550 hp 468 with dual holley's. I had 4 people on the boat with about 20 gal. of fuel. Is there any way to tell what impeller I have without tearing the pump down? That was 62 mph at 5500 rpm's. That doesn't sound very good to me. I would think I could get more out of this boat. Could there be something in the setup of the shoe, ride plate, ect:
And, is there a difference in mtr hp and shft hp. If so how do you determine shft hp?
Thanks for any and all comments
Bo

[hkunz]

What was the water like? I've had a boat slow down when i went from chop to glass.:idea:

[bo brown]

The water condition had a "mild chop " to it. Wasn't to bad but there were times I had to back out of it because it was a little rough. I figured the boat would do around 70 or 75. I think there was too much boat in the water. It could have been too much weight. 4 people = 750lbs fuel probably another 140 lbs. I don't know I'll try on the river tomorrow where the water is a little better for running jets. My buddy and I will take a look at how much boat is in the water versus the angles on the shoe. He supposedly knows how to check all that. I guess I'll know more tomorrow.
thanks for any and all help and suggestions.
Bo

[bo brown]

I would add pics but I have to figure out how to do all this first. I'll try and have pics up on Monday
Bo

[bp]

I'm new at all this jet boat stuff. Eager to learn though. bp you helped me last week with shoe angle question. I took my 17ft Rogers out yesterday. With a gps the boat only ran 62mph. I have a 550 hp 468 with dual holley's. I had 4 people on the boat with about 20 gal. of fuel. Is there any way to tell what impeller I have without tearing the pump down? That was 62 mph at 5500 rpm's. That doesn't sound very good to me. I would think I could get more out of this boat. Could there be something in the setup of the shoe, ride plate, ect:
And, is there a difference in mtr hp and shft hp. If so how do you determine shft hp?
Thanks for any and all comments
Bo
you can't tell what impeller is in it without pulling the bowl off and measuring it. 62 at 5500 is slow. but, you have 160lbs or so of fuel, 5 or 600lbs of extra bodies, and no real idea of how deep the boat is running (i.e., drag) at that speed. how certain are you that the tach is 100% accurate??? what kind of tach is it, and how long has it been in the boat? not uncommon for them to get way off, especially high.
next time you do this, after you get all the bodies out of the boat make another pass and see what it does, just for grins. at 5500, you should be a good bit over 70.

[bzking]

you can't tell what impeller is in it without pulling the bowl off and measuring it. 62 at 5500 is slow. but, you have 160lbs or so of fuel, 5 or 600lbs of extra bodies, and no real idea of how deep the boat is running (i.e., drag) at that speed. how certain are you that the tach is 100% accurate??? what kind of tach is it, and how long has it been in the boat? not uncommon for them to get way off, especially high.
next time you do this, after you get all the bodies out of the boat make another pass and see what it does, just for grins. at 5500, you should be a good bit over 70. Ditto...

[bo brown]

Well, I think we have found part of the problem. We took the boat out Saturday and a buddy of mine has discovered 2 things. (1) One of the accelerator pumps on the front carburator isn't pumping and (2) the back barrels on either carburator is not kicking in. We were running around with just the front barrels on each carburator. So I have to replace one of the pumps and then figure out the linkage on the 2 carburators. Maybe then we can get the speed we should have. Then I also found that one of the necks on one of my tanks was snapped off, so, I'll have to fix that. As for the tach, it's been in the boat I guess forever. I know it needs changing because Saturday my buddy said it was way off and hit it and the RPM's went down from 5400 to about 4400. So I 'll change that out too while I have all this work going on. Thanks for all your help, I need it.
Bo

[POPs@AggressorJets]

Bo Might help, 62MPH@ 4250 Rs, 20 1/2 Open Bow (Ultra) Not as fast a bottom as Rogers Stuff, Stock 454 Aggressor "A" Cut, so a Berk or other should read in at say 4650 Rs or around = 62MPH. (Radar Based Data on our first test boat) Dave. Bottom was cleaned up!
I would agree with BZkings #s