won't reach max rpm - slow to get up on plane

[CAMERON268Vista]

Hello - my boat has been having the same issue for 2 seasons now. It seems a lot worse in the hot summer weather - not as bad in the spring/fall season. Also worse once engine warms up and at operating temperature.

It takes a ridiculously long time to get up on plane - up to 90 seconds, sometimes close to 2 minutes if it's really hot and the engine is warmed up. when I first got the boat 4 seasons ago it took maybe 10-15 seconds (didn't actually time it) but definetely way better.

Also, it won't get up to max rpm. spring and fall i'm reaching around 4400 rpm, now in the summer i'm hitting about 4000 rpm.


additional info -
*I hydrolocked the engine last year and had a new engine installed - so new engine this season, same issue.
*2002 four winns vista 268 - 5.7 volvo pent Gi
*changed fuel filter last year and this year - no improvement
*based on what four winns has published - I'm getting the correct speed for the rpms.

any recommendations are appreciated - thanks in advance

 

[alldodge]

First thought is prop is to great a pitch and/or drive has to high a ratio

Has drive been replaced?
What pitch prop is installed?

 

[Buster53]

A couple things…first of all, a 268 is a lot of boat for a 5.7. Have you put more stuff on the boat? How much water and gas are in the tanks? Any chance you have a fair amount of water sloshing around the bilge? All of this can add a lot of weigh to the boat, slowing down performance.
BIG question (and we don’t know where you boat) if you are in salt or brackish water, barnacle build up on the bottom and running gear can quickly kill performance to the point you will never get on plane.
A couple years ago, my boat yard painted my bottom and running gear and whatever they put on the running gear didn’t work. In 10 weeks, my top speed went from 35 mph down to 27. I was getting ready to take a lengthy cruise, so I had to get a short haul just to clean the running gear so I could take my cruise.

 

[CAMERON268Vista]

First thought is prop is to great a pitch and/or drive has to high a ratio

Has drive been replaced?
What pitch prop is installed?

it's the same outdrive & prop I was getting good performance with 3 seasons ago - props in perfect condition. I don't remember off hand what pitch is on on it, but it's the prop recommended in the manual.

 

[CAMERON268Vista]

A couple things…first of all, a 268 is a lot of boat for a 5.7. Have you put more stuff on the boat? How much water and gas are in the tanks? Any chance you have a fair amount of water sloshing around the bilge? All of this can add a lot of weigh to the boat, slowing down performance.
BIG question (and we don’t know where you boat) if you are in salt or brackish water, barnacle build up on the bottom and running gear can quickly kill performance to the point you will never get on plane.
A couple years ago, my boat yard painted my bottom and running gear and whatever they put on the running gear didn’t work. In 10 weeks, my top speed went from 35 mph down to 27. I was getting ready to take a lengthy cruise, so I had to get a short haul just to clean the running gear so I could take my cruise.

Hi, I boat in fresh water only (lake huron and superior) it did come from brackish water 4 years ago, but it ran and performed fine the first two years.

Bilge is completely dry - I've actually never used the water system in the boat so water tank is emptly. I do keep it topped up with gas, but that was never a problem before. No extra gear compared to other years when it was performing good.

Again, one of the key components is that it is noticebly worse in warmer weather. Operates better when cool. not sure how that makes sense or what that could mean.

 

[alldodge]

new engine installed - so new engine this season, same issue.

Old and new engine doing the same thing

It's a 5.7Gi what?
Figuring it may be TBI but being 2002 it might be MPI
Has fuel pressure been checked TBI 30 psi, MPI 50-60 psi

 

[CAMERON268Vista]

Old and new engine doing the same thing

It's a 5.7Gi what?
Figuring it may be TBI but being 2002 it might be MPI
Has fuel pressure been checked TBI 30 psi, MPI 50-60 psi

it's throttle body - i believe Gi-B - we checked the pressure of the fuel pump last season. there was a low and high pressure spot to check - both were within spec.

 

[alldodge]

Gi-B is an MPI and uses the flat Dizzy cap

Lets just go with the TBI
Everything works but not enough power

Was timing set using base timing mode?
Is timing advancing as rpm increases?
Are there any codes?

Should have a MEFI 3 ECM so can check for codes with a resistor LED or digital voltmeter with tone. Place jump (paper clip) across pins A and B. Put meter on pins E and F then turn key ON (do not start)

Count flashes. Exp 12 is flash, short pause, flash, flash longer pause, then goes to next code. It repeats 3 times