OK let's talk about XB mods

[Todd D]

did you have your fuel ecu remapped? If not you motor starts dumping lots of fuel(running real rich) over 6,000rpm. Mercury did this to make the motos last and be more reliable.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Down Under &raquo;</TD></TR><TR><TD CLASS="quote">
Don,

Could you kindly PM me with a price to replace my TPI just incase mines found to be faulty.

I set in via timing light at the moment, -1 degree at idle, and about -14degrees at 3000rpm. Is this right?

After running the boat, come back tot he ramp and check it and it has maybe moved to +1 and -10 degrees.

Your thoughts / input are also very much appreciated.</TD></TR></TABLE>

Engine serial number?

Might be a good idea to set the TPI/TPS via a "voltmeter reading"....

[Down Under]

Thanks Don,

Serial number is OG30831

And what Voltage range should i be looking for?

And of the three wires which ones to i take the readings off.

Apologies for all the questions....

[492slayer]

David, the TPS needs to be set to .095 +/- .050 with the throttle closed, and should be max voltage of 3.80 +/- 0.10 at WOT. I set mine at the TPS with the needles into the wire coating. In the manual, you will find this...






*** I pierce the two top wires on my TPS to set it. Depending on which way you do it, the value will read + or - on the Voltmeter.... Don't forget that you have to turn the key on to get a reading

[kllr bee]

I am wondering the same thing as Todd. If you are running a 225 fuel computer the fuel will start dumping at about 6000 to protect the motor. I have found the the 250XB fuel curve works the best. As for the TPS setting, you need to get the Mercury TPS harness for that motor to acurately read the settings. Part number is 84-825207A1. I believe Don can get the harness for you also. I set mine a little high to ward off the dreaded lean sneeze that can occur in the 3 liter. I set at .101 and top out around .390 and motor runs fine. The thing to look for in the TPS tested is a steady upward voltage movement in the TPS all the way from idle to full throttle Also your exhaust tuner could be holding you back. I have heard numerous times that the 96 tuner was the most restrictive of all the 3 liter tuners.
Richard

[492slayer]

Richard, I also find that at around 1.00 the sneezing seems to disappear, but advance it too much and your hole shot suffers

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 492slayer &raquo;</TD></TR><TR><TD CLASS="quote">Richard, I also find that at around 1.00 the sneezing seems to disappear, but advance it too much and your hole shot suffers </TD></TR></TABLE>

Hence the specification of .950 (+/- .050), which results in an acceptable range of: .900-1.00 volts at idle. A higher reading results in a "richer" mixture, lower reading results in a "leaner" mixture.

I can still get you the 825207A1 TPS test harness, if needed.

[Down Under]

Great Info all - thanks very much

anyone have an XB fuel computer for sale?

What Todd is saying makes a lot of sense seeing the symptoms im experiencing, at WOT the engine starts to feel fat or spongy, as in the revs are there but little power - if that makes sense.

[Down Under]

Could it be possible that i need more air?

Would an SVS help over the 4 shutter intake, anyone have any experience with SVS on the PM or other?.

[492slayer]

Contact Eric Simon, he can reprogram your ECU's from the 225 to whatever setup you are looking for. My original 225 ECU's power my 335HP setup. Also see what he can do for you regarding an intake. His number is (760) 440-9334 and e-mail is info@simonmotorsports.com

[Todd D]

Richards got a set of 250xb computers he'd sell you

[2fastr1]

I`m currently running pennzoil full synthetic oil in my Pro XB. Is this a good oil to run?

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2fastr1 &raquo;</TD></TR><TR><TD CLASS="quote">I`m currently running pennzoil full synthetic oil in my Pro XB. Is this a good oil to run?</TD></TR></TABLE>

Not going to get into "brands" here.... but I don't recommend "FULL" synthetics for any "steel-sleeved" engine. A "Synthetic Blend" would be a better choice, IMHO. You'll receive the benefits of BOTH primary components (synthetic and petroleum-based lubricant).

[kllr bee]

I run Mercury Premium Plus in my motor. Never ran nothing else. I do have a set of 250 XB computers to sell if anyone is interested they can send me a message. They will be a large step up from 225 EFI computers.
Richard

[Down Under]

Richard,

Can you please PM me with a price for the XB computers.

do you think i should look for an SVS also?

Thanks

[modvp]

This site is very informative and the members are very knowledgeable. My question is, I have a 1999 250 EFI, what gains will I obtain with a set of 250XB computers?

[tb cat]

I have a 1996 225 efi also. The power head is off right now due to a piston break. I would like to do something to the exhaust tuner to help the bottom end hole shot. Have been trying to find info to do this an found this site last night. It seems Kllr bee put you in the right direction on the tuner. Would you please share the mod info with me. Thanks


Modified by tb cat at 5:43 PM 3/11/2010

[kllr bee]

The 250 EFI is basically a 225 with a little more timing and fuel. The XB computers do much more agressive fuel and timing additions. They will help but you also need to add more compression to the equation to get the full effect. I see that your motor already has the 4 butterfly intake so you are getting the air intake you need. Computers and heads would help you a bunch.
Richard

[hank 03bullet]

hey guys im new to the site, was wondering what the mods were to the cowling? all the motor mods info is great!

[kllr bee]

There is a post I did on cowl mods where you found this post. It has pictures and instructions.
Richard