'08 300XS surging during idle and low RPMs

[Ranchdip]

Hello,

I posted a reply on the same subject over in the Merc 2.5 forum but was asked to give the 3.0 forum a try. Sorry about the double posting if you've already commented.

I've only had my Triton 21X2/300XS out a couple times and I've noticed a short spurt of surging at low RPMs (under 2000rpms). It will surge while idling intermittently. It kind of sounds like it's missing a little. However, I have asked a couple people about this and they said it was normal for the 300XS. Has anyone else heard this is normal?

Thanks

[EuropeanAM]

If you can answer a couple of simple questions.... I'll do my best to help:

-How many hours on your engine?
-How many hours since LAST ENGINE SERVICE (including spark plugs)
-What spark plugs do you have in your engine?
-Fuel Age/Brand and Grade? Have you tried a DIFFERENT brand fuel?

[Ranchdip]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by EuropeanAM &raquo;</td></tr><tr><td class="quote">If you can answer a couple of simple questions.... I'll do my best to help:

-How many hours on your engine?
-How many hours since LAST ENGINE SERVICE (including spark plugs)
-What spark plugs do you have in your engine?
-Fuel Age/Brand and Grade? Have you tried a DIFFERENT brand fuel?

</td></tr></table>

- 190 hrs
-The 300XS was serviced on 6-15-10 but did not get an impellor. It got plugs (not sure which ones), lower unit lube and a fuel filter.
On 7-27-2009 it was in for a loss of power and had the compressor replaced at 137 hours as well as plugs, fuel filter and a boost pump.
On 4-3-2008 the gear case was replaced under warranty.
- Since I've only had the boat a few months I'm not sure what gas was put in before I purchased it. I recently put Connoco 93oct in it.

Thanks so much!

[EuropeanAM]

Try a fresh set of IZFR7M (NGK) Spark plugs before doing anything else. Preferably gapped at .040-.044.

Also, ensure you're running QUICKLEEN in every tank of fuel.

If the problem persists.... let me know.

[Ranchdip]

Thanks so much for the info! I'll definitely give this a try and will let you know how it works out.

[Ranchdip]

Well, after changing plugs, new gas in tank, quickleen, and stabile additives I still have slight idling problems but now for some reason the engine starts to bog down when I accelerate to get up on plain.

Any thoughts?

Thanks!

[EuropeanAM]

You're probably going to need to enlist the "hands-on expertise" of a Certified or Master Technician soon, or at some point. I'll be glad to assist.... but there's only so much that can be done "blindly".

Some of the things that need to be checked:

-FUEL LINE and PRIMER BULB (see: http://www.bbcboards.net/zerot...first )

-TPS: Perfrom a VOLTAGE SWEEP TEST watching for irratic increase or decrease of voltage

-AIR/FUEL pressure tests THROUGHOUT the RPM range (especially where the problem is present).

-Auto Self Test PLUGS OUT OF CYLINDER HEAD- spark tester attached (on the Computer Diagnostic System)

[Ranchdip]

Thanks so much for the info. Man, I find myself wishing I had my old 225EFI back. Not a single issue for 6 years.

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Ranchdip &raquo;</td></tr><tr><td class="quote">Thanks so much for the info. Man, I find myself wishing I had my old 225EFI back. Not a single issue for 6 years.</td></tr></table>

Those were great motors.... but they're not fairing much better, running today's fuels.