2500 scr Lack of top end power???

[Mr Hemi]

Boat Top End is 4500 RPM. 2002- 5.0 MPI.

At 4200 RPM theres lots of throttle left, so when I open it up all the way, it does not translate into a lot more RPM (4500 RPM), but I do get more speed???.
But boat never gets above 4500 RPM at 41 MPH.

Dont care about top speed, but would like to see a bit more RPM to clean it out a bit.
New Prop, new plugs, wires, New manifolds and risers, thermostate etc.

Id there a govenor or something, or is my prop just maxed out???.
The only thing I know is Starboard manifold gets quite hot, could it be pulling timing???
Boat runs between 175-180 degrees, never goes above.

Wish I knew where to start.
Appreciate any input.
Thanks Grant

[mmwjr]

The WOT for your engine is 4400-4800 rpm so you’re in range. Not sure I would make any changes to get 300 rpm especially since this is not an rpm for constant operation.

[Mr Hemi]

I thought my Max rpm range was 4600-5000 RPM???.
I am going boating today and will check it out just to be sure, but believe it said rpm on manifold cover.

The 5.0 L model is a V8 with 260 horsepower and a throttle range of 4,600 to 5,000 rpm.
Sorry if my mistake.
Any input would be great.

[mmwjr]

If you are correct about the WOT range I’m not sure I would still make any changes over 500 rpm as I stated before this is not a rpm for extended operation. In the future when needing a new prop you could drop the pitch by an inch to get the rpm up.

[Mr Hemi]

I just bought a smartvessel, and will confirm my tac is right.
Maybe i am closer to 4600 range than I think.

Still would have liked to see my max rpm reached, but no big deal.
Thanks for your input.

[Mr Hemi]

The VessleView confirmed my tac is not correct.

My Max. RPM is around 4700 rpm which is great,not the 4400RPM that my guage shows.

My Temperature is also much lower than the 180 that is on my guage cluster.
Well worth the investment.

[mmwjr]

Originally Posted by Mr Hemi

The VessleView confirmed my tac is not correct.

My Max. RPM is around 4700 rpm which is great,not the 4400RPM that my guage shows.

My Temperature is also much lower than the 180 that is on my guage cluster.
Well worth the investment.

Thanks for letting us know. I have found it common for boat helm gauges to be off.

[Mr Hemi]

Appreciate the help.

[mmwjr]

Originally Posted by Mr Hemi

Appreciate the help.

You’re welcome!