It's the mag MPI motor it's not the L29 truck motor so I believe the internals and hp are a little better.
I know it's a little on the heavier side I wasnt starting this thread to complain about my MPH but to merly verify its close to what it should be. I just was curious why I can't seem to spin a 23P mirage when most others are running the 23P with same or similar boats was all. The guy I got it from said he had the issue of it not wanting to come out of the water with the 23P so he put the 20 on it.

I'm looking for a good used 21 mirage plus to try so I can see if it'll work, I would say if it'll come out of the water with the 21 it'll prob give me that 2-4mph I'm missing... Why it's taking a 21 to do what most do with a 23 I can't explain? Is it the 200lb subs up in bow? I don't know? But it's not like I'm at 6 passengers and a cooler full. It is pretty light load with just the subs up front

It's the mag MPI motor it's not the L29 truck motor so I believe the internals and hp are a little better.
I know it's a little on the heavier side I wasnt starting this thread to complain about my MPH but to merly verify its close to what it should be. I just was curious why I can't seem to spin a 23P mirage when most others are running the 23P with same or similar boats was all. The guy I got it from said he had the issue of it not wanting to come out of the water with the 23P so he put the 20 on it.

I'm looking for a good used 21 mirage plus to try so I can see if it'll work, I would say if it'll come out of the water with the 21 it'll prob give me that 2-4mph I'm missing... Why it's taking a 21 to do what most do with a 23 I can't explain? Is it the 200lb subs up in bow? I don't know? But it's not like I'm at 6 passengers and a cooler full. It is pretty light load with just the subs up front

Got ya. I thought the 24 was a 7' beam boat.

If your 20 pitch is a actual 20 pitch you still need to verify the drive ratio or you will be banging your head forever, keep looking and find a 21 pitch BUT I would pull the drive and count the ratio meanwhile,won't cost you anything except a hour of your time, like I said, you should inspect and grease the u-joints and coupler anywas if you never have !

Ok well I'll do that but like I said I'm very new to the boat mechanic world... Do I pull the top off drive off?? Sorry for newbie question

I have a 25 OL with a 502 Mag MPI. Best I've seen is 67 GPS, I was alone, 1/4 tank of gas and using and un labbed 23 m+. Honestly I don't like the 23 m+ if I have more than 3 people on board. If I have 4 or more I will run my 21 rev4. Prop has great holeshot, same cruise and top end is still good with 64 gps with 4 people, half tank of gas, coolers, etc. I get 62 gps with a full load of 6 people, gear, half gas, etc.

Gee. Right from the horse's mouth.
Fordtough150 has a newer, bigger, better engine than you and
he does not like to run his Mirage Plus 23P with crew aboard.
I wonder why???

Now I read that you have 200 lbs. of subs mounted in the bow
of your cuddy? What other surprizes do you have for us? A
baby Hippo where the porta-potti was? What you have done in
essence is hang a fat chick off your bow rail. Our boats are
designed to have a slightly "nose up" attitude when running
balls out. You altered your boat's balance and increased it's
wetted surface. That results in a loss of speed.

No you said you did your prop testing with 5 people and..........

Martin - if you think what you're doing is running "light" then
you're just pissing in the wind with the info in this thread.

O.K. Folks!!! Back to our regularly scheduled discussion of
7.4L engines, blowers, and gear set changing.

Alright some of you pay attention others not do much. I appreciate some of the insight and info from the most of you. Once again I wasn't complaining I was merely checking my stats to see if it's what it should be per the conditions. I bought the boat from a hack job half stupid man and i have spent more time wrenching and correcting issues since I bought it and I was to a point to were I thought things might finally be correct

Plus I needed real life experience and info on a procharger on a 454 MAG MPI at 5 psi

That is all

Martin,

They are getting frustrated because this thread is many pages in and no one has solved what they think is another problem.

Me personally, I don't think you have a problem. T think that is what your boat runs with that prop, simple. U get the whole gear ratio thing, but I still think you might be at a 1.5, and that 4 blade prop is way off...I have seen it before, props that are designed to solve problems in boat are rarely spot on (ie rev4 and hydro) they pull more pitch than they claim.

If he was a hack job, please post every thing that he has changed, it will help us help you investigate futher problems. Even if it is something you have fixed, post it....will only help.

One other thing you have to understand is many people post their top speed number as the one they hit on that perfect day, in the perfect conditions, on a cool day in the fall or spring. You are not that far off.

Just to clarify it's a 3 blade prop and I called a prop shop he thinks we are close enough to where it needs to be not to mess with it. For what it's worth he said the tech props are good props.

It was multiple test runs in multiple conditions it runs 58 consistant and like you said I feel it's good actual data. I might be new to boat stuff but I build race cars from ground up.

As far as issues go it had a serious electrical issue when I got the boat, I have since replaced 4 batteries, distributor cap, rotor, coil, wires ect.

It had an issue that was causing the fuel pressure to drop and pump to cut out at 3,000 rpm so I listened to what a few on here believed it to be an put 8 new injectors in it, that didn't fix it so I put a complete new cool fuel system and regulator on it which also didn't fix it. Ended up being the coil or the coil ground.

I still feel like there is an electrical issue and I'm sure it's a ground, any time you hit a switch or operation the voltage gauge jumps or drops if holding an operation it'll drop 2bolts on the gauge which does that mean its dropping 2 volts in actuality? No but that's what it shows, in my opinion it shouldn't move a mm as I have 4 batteries wired in that are used when battery selector is on all.

Is there a possibility that the alt is bad? Yes
Battery bad even though all are brand new? Yes

The wiring seems to be a common problem in boats as most are fiberglass so grounding can be tough. I generally replace his old connections daily and will continue too. Any splice or wire connection he used was not a weather tight connection nor brass or copper so a lot of them are corroded and breaking. I'm replacing correctly as I find them but I've made two boat trips one after 10 hours of driving where I spent the ENTIRE weekend FIXING the boat not enjoying. This is what I'm trying to avoid