08 250 pro xs rough idle

[rcooperbass9]

i have a 2008 250 pro xs that had the power head replaced at around 100 hours now has probably a little over 200. I took it out this weekend and noticed for the first time that it is idling rough especially at a high idle (trying to get through a long no wake kind of quick!) But the motor runs completely fine off idle. The rough idle does not feel as rough as a misfire, just a little shakey. I am not positive but i may have heard a little bit of a belt squeak type noise while it was idling rough also kind of in between shakes. I have had no alarms, the only thing i am unsure of is my fuel lines, have not checked to see if they are the updated style or not, probably not! And the cranking battery does need to be replaced with one that meets the mercury requirements. I have never noticed this before, have read that plugs may be the problem which i am going to replace this winter. any help greatly appreciated

[EuropeanAM]

Definitely address your fuel lines and battery. One of the hard lessons "experience" has taught me is to "Always address the OBVIOUS before looking for the OBSCURE".

On that same note- inspection of the belt, tensioner, air compressor, and air compressor pulley/bolts are certainly in order.

Spark plugs should be replaced with IZFR6J plugs, gapped at .044". Gap is critical to proper idle performance.

See the following post for more information on ANNUAL Maintenance Recommendations:

http://www.bbcboards.net/zerot...gines

[Phoenix Jim]

any idea what caused your blowup? I have the same motor. Also, my 08 had the old lines and I got them replaced. Do yourself a favor and get the sears PM-1 battery. Your merc will love you for it because those motors require a lot of juice.

[Hawgwalker]

Have the same issue also with new power head plus will get an alarm if long idle is first thing before going on plane as in a long no wake from the ramp. 2008 250xs

[crizzel]

That sounds like a overheat alarm.. I'd check your T stats, or get the motor checked out.

[rcooperbass9]

my blow up was caused by the lower unit locking up at around 90 hours it took out "6 cylinder.

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by rcooperbass9 &raquo;</td></tr><tr><td class="quote">my blow up was caused by the lower unit locking up at around 90 hours it took out "6 cylinder. </td></tr></table>

Hmmmnnn.... that's an unusual combination.

I'd start with an inspection of the spark plugs. Confirm PROPER gap (.044"), and inspect the porcelain surrounding the electrodes for ANY lines that run EVEN REMOTELY lengthwise.

"If it looks like a crack- or a lengthwise line: Replace the Plug!"

Be glad to assist with the others (including overheat)... but let's get those into a separate post to avoid confusion.

[rcooperbass9]

i am going to check the plugs this winter, but what is the mercury or your recomendation on plugs based on hours? the plugs were replaced around 90-95 hours and i havent had the hours pulled but i would guess i have somewhere around 220 on it now.

[EuropeanAM]

See the following post regarding recommended ANNUAL Maintenance.


http://www.bbcboards.net/zerot...gines