2001 Mercury Optimax 200

[futurebassmaster57]

I need help! Here is the problem... First, it is an intermitant problem. One day the motor will run amazing at 5500 rpm, the next time I start it up it may only run 4800 rpm, or 5100 rpm. I have had it looked at my 2 different mercury dealers, and no one can figure it out. I don't know what to do now, or where to take it. Probably 4 out of 5 times it runs at 4800. It is really agrivating. I have looked everywhere to see if anyone has the same issues, and I can not find any info. I was told by a Mercury tech to run Quickclean through it in every tank, which I do religiously. It has not helped. Anyone have any ideas?

[EuropeanAM]

Sounds as though you are either in "Guardian" (this should show as a fault when the engine is connected to the Computer Diagnostic System, or a DDT),

-OR-

You are down a cylinder at times.

Since the problem is "intermittent".... it's likely that the problem is electrical in nature (not guaranteed, just "likely"). Possible causes include a coil, coil driver, spark plug lead, spark plug, direct injector or fuel injector.

A good starting point would be to test for spark WHEN THE ENGINE IS DOWN ON POWER. If you don't have a suitable spark tester, you may be able to utilize a timing light.... connect the inductive pickup lead to one spark plug wire at a time, while watching the light to see if it "flashes".

Always check the basics: Compression, SPARK and FUEL/AIR Pressure/Volume/Delivery.

[futurebassmaster57]

I appreciate the feedback. If anyone else has any it is glady taken too! Now, I just need a place to run it since I live in Nebraska and there is no water that doesn't have a foot of ice above it. If I was to hook it up to a hose can you run it full blast or should it only be idled at that time?

[EuropeanAM]

DO NOT exceed 1200 RPM (just above idle speed) on a hose flush attachment.

[futurebassmaster57]

That's what I figured. Guess I have to wait til spring....

[futurebassmaster57]

What spark plugs is Mercury suggesting for this engine now? I have heard they have changed a couple times.

[EuropeanAM]

NGK (IZFR5G), Gapped at .032-.033 (should be at this gap when removed from the box), per Service Literature.

IGNORE the gap shown for any "PZ" platinum plug on the Emissions Decal.

[futurebassmaster57]

Thanks, I appreciate all the help