2008 Mercury 250 Pro xs

[lfadaol]

After fishing a few weeks back, motor started loosing power then picking up again. Went to get on step and bogged down for 50 to 100 yards, then would only get up to 3200 rpms. Dealership changed a coil and next trip acted up again. Dealer rechecked and could not find anything. Last week made a trip, eight miles down river motor started cutting out, I slowed down and took off again ran fine until late in the afternoon. Started loosing power until boat would not stay on step. when able to stay on step, no more than 3200 rpms, the motor would rev up and down and come off plane again. Closer to the landing ran fine with full power. Brought back to dealer, spoke to him yesterday, ran 20 mile trip with no problems. Asked him to keep and run until acted up. Any info I can give the dealership to help solve this problem?

Thanks


Modified by lfadaol at 9:00 PM 11/13/2008


Modified by lfadaol at 9:05 PM 11/13/2008

[ssimpala71]

You still "may" have another coil acting up. There are other possibilities as well but sometimes these coils will "come and go" to the point of aggrivation!! Had a 225 the other day that I had to run for nearly 30 minutes before I could "hear" a change happening. By the time I got back over to the motor it was back "on" again and alls fine. I knew it was coil laying down, but I had to have presistence to "catch" it so I could find out which one it was!!

[EuropeanAM]

+1

I've had about 85% likelyhood of catching these faulty coils by running an "auto self test- plugs OUT of cyl head" on the computer diagnostic system. Might have to run the test cold, warm, and hot before the coil shows up... but this test GREATLY improves the odds of finding a coil that's dropping out.

Keep in mind- fuel is also a possibility! I'd recommend they check air and fuel pressures, test the air and fuel systems for leaks (air rail with regulated shop air pressure), and perform a fuel restriction/capability test. Of course... this should all be done AFTER they are sure that a coil is not the culprit.

Be sure to ask them to check and see if there are any "overspeed in neutral" faults... and let me know if there are.

[dbow01]

I have an 08 mercury 250 pro xs. The problem I am having is at full throttle it will periodically die to an idle speed. It acts as if it is almost starving for full. Has any one had any problems like this... I would hate to send in for warranty work and be without a boat for 3 to 4 weeks. If it is just an easy fix... Any suggestions would help...
Thank You

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dbow01 &raquo;</TD></TR><TR><TD CLASS="quote">I have an 08 mercury 250 pro xs. The problem I am having is at full throttle it will periodically die to an idle speed. It acts as if it is almost starving for full. Has any one had any problems like this... I would hate to send in for warranty work and be without a boat for 3 to 4 weeks. If it is just an easy fix... Any suggestions would help...
Thank You
</TD></TR></TABLE>

If it just "sits down" to idle speed- without stalling or "heavily surging".... odds are high that the PCM has enacted "Engine Guardian" due to a fault (you SHOULD hear a 6-second warning horn as well).

I would recommend having this engine put on the Computer Diagnostic System, to read the Freeze Frame (Fault) History (and the run history). Be sure to get a printout for future reference.... would be glad to take a look at the printout if you have any questions.

[dbow01]

When it slows down it locks up the steering and you basically lose control. There is no throttle response and you just have to do let it die to an idle. If you shut the motor off and restart it may run fine for the rest of the day or it may do it five more times that day... But I will do what you suggested thanks...

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dbow01 &raquo;</TD></TR><TR><TD CLASS="quote">When it slows down it locks up the steering and you basically lose control. There is no throttle response and you just have to do let it die to an idle. If you shut the motor off and restart it may run fine for the rest of the day or it may do it five more times that day... But I will do what you suggested thanks...

</TD></TR></TABLE>

All of what you described (except for the steering comment) sound as though the engine is indeed enacting "Guardian".

Get it in and get it checked.

The steering SHOULD NOT be locking up- that would be a separate issue (separate system).