Need help with 2003 Merc 250XS

[Nova Kaw 650]

Ok, so just flat foot it right from the start?

You should be from idle to WOT within a couple of seconds.

[Savage]

Ok, so just flat foot it right from the start?

Trim motor ALL the way down and tucked in towards the transom.
Put the boat in forward gear.
Mash the pedal to the floor.
When the boat is on plane, start to trim up.

[crashxx]

Trim motor ALL the way down and tucked in towards the transom.
Put the boat in forward gear.
Mash the pedal to the floor.
When the boat is on plane, start to trim up.

Should it bog all the way to WOT and then all of a sudden come alive?

[EuropeanAM]

Should it bog all the way to WOT and then all of a sudden come alive?

Try to explain this statement without the word "bog", please.

[crashxx]

I'm not good with descriptions. I'll get some video next week when I can get on the water.

[bassburch]

INcidentally unless you have a very light boat, the 27P Bravo is way to big. I have a 250 pro xs on a 2009 206 champion and I am turning a 25 P Bravo at about 5700 to 6000 depending on the load. What boat do you have?

I disagree. Myself and multiple others with 03/04 521VX//250XS are having excellent results near max RPMS with 27P Bravo 1XS. The prop is built for heavy loads.

Here's my routine for max performance:

1) Trim all the way down, jackplate at ANY position. Higher JP position is great for taking off in shallow water.
2) Place in gear, idle for few seconds, then hammer throttle down to max.
3) You should see about 4K RPMS as you come on plane, once the prop aerates from properly set vent holes.
4) Slowly ease off on throttle after you're on pad and start trimming up.
5) Trim up and apply more throttle until at max trim WITHOUT a giant rooster tail.
6) Raise jack plate up a tick at a time until water pressure begins to drop, then tick it down and drive.

Doing this with 2 guys, 1 tank gas, and tournament load, I can hit about 72MPH at around 5700-5750 RPMS (the max for an 04 XS).

When the livewell is full getting on pad takes 1-2 seconds longer.

When by myself she literally JUMPS on pad instantly.

See: http://www.bbcboards.net/showthread.php?t=911286

[crashxx]

I disagree. Myself and multiple others with 03/04 521VX//250XS are having excellent results near max RPMS with 27P Bravo 1XS. The prop is built for heavy loads.

Here's my routine for max performance:

1) Trim all the way down, jackplate at ANY position. Higher JP position is great for taking off in shallow water.
2) Place in gear, idle for few seconds, then hammer throttle down to max.
3) You should see about 4K RPMS as you come on plane, once the prop aerates from properly set vent holes.
4) Slowly ease off on throttle after you're on pad and start trimming up.
5) Trim up and apply more throttle until at max trim WITHOUT a giant rooster tail.
6) Raise jack plate up a tick at a time until water pressure begins to drop, then tick it down and drive.

Doing this with 2 guys, 1 tank gas, and tournament load, I can hit about 72MPH at around 5700-5750 RPMS (the max for an 04 XS).

When the livewell is full getting on pad takes 1-2 seconds longer.

When by myself she literally JUMPS on pad instantly.

See: http://www.bbcboards.net/showthread.php?t=911286

I tried to take off with my jack plate all the way down and she wouldn't spin up. I had full fuel, two guys (170 each) and full live wells. I'm thinking I may have a bad coil pack. Probably going to take it in and have it checked. With the bravo 27, I had to have my jack plate up on 4 or 5 to get out of the hole.

[crashxx]

BTW, just started another thread with some good stuff for 521's that gonnabe figured out.

http://www.bbcboards.net/showthread....61#post9444561

[Nova Kaw 650]

I tried to take off with my jack plate all the way down and she wouldn't spin up. I had full fuel, two guys (170 each) and full live wells. I'm thinking I may have a bad coil pack. Probably going to take it in and have it checked. With the bravo 27, I had to have my jack plate up on 4 or 5 to get out of the hole.

Have you actually trimmed all the way in and stomped the throttle down as recommended several times above?? If you did and it didn't come out of the hole, what were the RPM's?
I think you may be chasing a ghost if you haven't tried it.

[crashxx]

Have you actually trimmed all the way in and stomped the throttle down as recommended several times above?? If you did and it didn't come out of the hole, what were the RPM's?
I think you may be chasing a ghost if you haven't tried it.

I have not taken note of RPM. I'll get it to the water next week and see what my results are.

[bassburch]

CrashXX,

Your only problem that I see is that you are running too big of a prop. Who decided on this size propeller?

Read this, you have way too much prop. I would jump to a 25 Bravo and everything will work fine. Read this...

http://www.bbcboards.net/showthread.php?t=678384

More bad advice. Z521 and 250 Pro XS is a completely different setup. Higher max RPM and different hull. A 250 Pro XS needs a smaller prop to hit higher RPMs. OP needs to stay around 5700 RPM and needs a larger prop to get there. Otherwise he'd be hitting the rev limiter and leaving MPH on the table.

The other solution is to change the ECU out to allow for a 6K RPM. THEN a 25P bravo 1 xs makes sense.

I think the OP has other issues with the motor or perhaps vent holes that need to be addressed.

[crashxx]

On my 27 Bravo I've got two solid plugs in it and all other holes are open.