2003 225 opti surging....

[brandonb]

On the way back to weigh in yesterday my motor starting surging, it was pretty rough out, when I could run WOT it would "surge". It would slow then pick right back up to normal. When I got in the real rough stuff and had lift and work the throttle it seamed fine, quick throttle response and normal power to clear the waves.

I always buy fuel at the same station except yesterday morning, fished Friday, Saturday and Sunday and it ran fine until Sunday afternoon. Friday and Saturday was the fuel I always buy, Sunday was fuel from a station I never buy fuel from.

Could this possibly be water in the fuel or something worse?

[EuropeanAM]

Bad fuel is possible.... as are several other items (such as primer bulb, pickup tube in tank, pulse fuel pump, VST float issues, etc. etc.).

The FIRST item I'd recommend checking is the FUEL LEVEL. If your fuel level was low (perhaps 1/4 tank or lower), it's possible that you were actually picking up air, and simply "running out of fuel" due to the rough water. I would be particularly suspicious of this if things evened out and operated fine in "smoother seas".

Water in fuel can present with a similar symptom. The best way to rule this out is to drain the contents of the water separating filter chamber into a glass jar, and inspect the contents of the jar for "water separation" at the bottom.

[brandonb]

I bought a new fuel filter, fuel line and primer bulb yesterday, gonna replace that stuff today. I was told the station I normally buy fuel from has up to 10% ethanol in their fuel, also gonna put an additive in my tank. I had about half a tank when this started, it evened out and ran fine when I could no longer run WOT full time cause I was having to work the throttle.

Where is the water separating filter chamber?

Thank you for your help.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hook’em 203 &raquo;</TD></TR><TR><TD CLASS="quote">Where is the water separating filter chamber?</TD></TR></TABLE>

There was a production change in the filter/VST design in 2003 (yours could be either version).

IF the separating filter is a "spin-on cannister" (looks like an oil filter), don't worry about a chamber (you don't have one).

If the separating filter is a "red-capped thread-in cartridge"... the chamber is the housing that the filter screws in to.

[brandonb]

Thank you for your help.

Mine had the red thread in type.
It didn't appear to have any water in the fuel however, my fuel line was trashed, the inside of the line was broken up and falling apart and my fuel filter was pretty dirty.

Got all of that changed out and added Sta-bil to my tank, hopefully that was the problem. With the items above replaced if my motor still does the same thing, could it be a coil going bad maybe?

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hook’em 203 &raquo;</TD></TR><TR><TD CLASS="quote">Thank you for your help.

Mine had the red thread in type.
It didn't appear to have any water in the fuel however, my fuel line was trashed, the inside of the line was broken up and falling apart and my fuel filter was pretty dirty.

Got all of that changed out and added Sta-bil to my tank, hopefully that was the problem. With the items above replaced if my motor still does the same thing, could it be a coil going bad maybe?</TD></TR></TABLE>

Possibly.... but if you had fuel line issues, I'd suggest you ensure that the line and bulb were BOTH replaced (all the way from the tank to the engine) with OEM Mercury line (use only the new EPA approved, ethanol resistant line).

Also highly recommend you pull the pulse fuel pump apart (since it's upstream from the filter), to check for debris in the pump. This is relatively common- since you're there, obtain a 21-857005A1 fuel pump kit ($21) so you can rebuild the pump.

[brandonb]

I replaced the line from the tank to the engine and the primer bulb, I did it myself so I know they were changed, and snaking the fuel line through the wire loom wasn't exactly easy

The pulse fuel pump, is this something I can do or should I have a certified Merc mechanic rebuild it?

The fuel filter was dirty in color but did not have any debris.

[EuropeanAM]

The pulse fuel pump is quite simple to rebuild.... and the 21-857005A1 kit comes with an instruction sheet.... which you should be able to follow with little or no difficulty.

That's where I'd start, since you're replace the line & bulb. See how it does after that.... if you still have any issues, I'll be glad to assist further.

[brandonb]

I'll pick a kit up today.


Thank you for your help, very much appreciated....