merc 225 efi quits running

[LaTriton]

Today while running across the lake at my efi quit running. It cranked right up and I took off again. Later on it happened again. I noticed that as long as I was running under 4000 rpm, it was fine. When I exceeded 4000, it would stall and quit; but would crank right up. I checked the spin on filters and did not have any water or trash in them. Any ideas?

[Todd D]

The primer bulb, fuel lines and the likes. The new fuels are hard on all this and it's relatively easy and cheap to replace. Think of it as peace of mind maintenence.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd D &raquo;</TD></TR><TR><TD CLASS="quote">The primer bulb, fuel lines and the likes. The new fuels are hard on all this and it's relatively easy and cheap to replace. Think of it as peace of mind maintenence.</TD></TR></TABLE>

+1 Add pulse fuel pump diaphram kit to that list as well!

Did you happen to note your battery voltage when it stalled?

When stalling, was it a "quick shutdown" as if a switch were flipped (electrical), or a gradual "fuel starving shutdown bog" situation?

[LaTriton]

Most of the time It was a sudden off. just like turning the key off. A couple of times it just choked down and I was able to keep it idling. It starts immediately after that.

[EuropeanAM]

You may also want want to monitor your battery voltage WHILE THE ENGINE IS SHUTTING DOWN.

This is most effective if you connect a voltmeter DIRECTLY TO THE BATTERY.

If voltage is above 14.7VDC, the ECM/ECU may actually be "shutting down" to protect itself.

[LaTriton]

Thanks, I will check it and update you guys. Thanks for your responses. I have the voltage read out on my Lowrance graph. I assume this would be accurate enough to check it.
If it is the ecm cutting out to protect inself, what are some of the possible reasons for this?


Modified by LaTriton at 6:16 PM 9/8/2009

[EuropeanAM]

I would recommend a voltmeter AT the battery (don't trust something as far away as the dash).

Possible causes: Poor electrical connections (at battery, grounds, or charging system), or VOLTAGE REGULATOR FAILURE.

[LaTriton]

Today I tested the motor again. I hooked up a voltmeter and ran it up to the console. It quit running again, but I misjudged earlier report of 4000 rpms being the limit. It is quiting at above 5000 rpm. The voltage at that point is a max of 14.45 volts. Same scenario; sometimes it quits completely and other times I am able to feather the throttle and keep it idling. When I first started, I did not exceed 4000 rpm until it warmed up. When I nailed it at approx 5000 it quit. Could it be starving for gas at max throttle? I was told by someone to suspect the low pressure fuel pump.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LaTriton &raquo;</TD></TR><TR><TD CLASS="quote">Today I tested the motor again. I hooked up a voltmeter and ran it up to the console. It quit running again, but I misjudged earlier report of 4000 rpms being the limit. It is quiting at above 5000 rpm. The voltage at that point is a max of 14.45 volts. Same scenario; sometimes it quits completely and other times I am able to feather the throttle and keep it idling. When I first started, I did not exceed 4000 rpm until it warmed up. When I nailed it at approx 5000 it quit. Could it be starving for gas at max throttle? I was told by someone to suspect the low pressure fuel pump.</TD></TR></TABLE>

Based on this description, it's unlikely that a voltage issue is your problem.

Much more likely is a fuel DELIVERY or FUEL PUMP issue. Possibilities include:

-Pickup tube in fuel tank (or actually no fuel in the tank- it does happen)
-Anti-siphon valve
-Fuel Line and/or Primer Bulb (use OEM ONLY here)
-Pulse Fuel Pump
-VST float sticking, trash in VST, float improperly set
-Fuel Filter restricted (debris)
-FINAL FILTER in VST RESTRICTED (if the outlet at the fuel pump is 3/4".... there's a filter underneath)

A good place to start is to monitor fuel pressure while running the engine.... watch for fuel pressure falling off just as engine "stumbles".

[LaTriton]

Thanks Don, that is what I am thinking. It seems as though it is running out of fuel. By the way, I put 100 dollars worth of non ethanol in it just 3 weeks ago, so I am sure the tank is good. I am going to install a new diaphram and also check the final filter as well as change the bulb. Hope to drive it Tuesday evening. I will keep you undated.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LaTriton &raquo;</TD></TR><TR><TD CLASS="quote">By the way, I put 100 dollars worth of non ethanol in it just 3 weeks ago, so I am sure the tank is good.</TD></TR></TABLE>

Just a "side note" to the above comment:

Switching back and forth between "E-10 and non-ethanol fuels" can be SUBSTANTIALLY more troublesome than ethanol enhanced fuel itself. In many cases, the fuels are simply INCOMPATIBLE, and induce what's known as "phase separation" (Sherm has a good post regarding this subject over on the Mercury Board.... pinned to the top). It's a good read.

[bluewingjb]

Hey La Triton I am having the exact same issues with my 97 Mariner 225 Super Mag.. Finally this weekend it died and will not restart which I would rather have happen as whatever was the problem has finally failed. I have already changed the primer bulb, moisture separator, high pressure fuel pump, have good fuel, inspected the tank and hoses as well. No water in my fuel either. I am curious as to what you find was your problem

Thanks
Wes

[rtriton02]

I had this exact same thing with my 2001 225 Efi. Same rpms and all. It would really stall out bad when I would hit a wake hard. Talked to a freind of mine (Mercury Tech). He goes to the boat cuts the grey Mercury fuel line and the inside of it had started breaking down real bad. Replaced it with some new fuel line and that took care of the problem. Just an idea.

[bluewingjb]

rtriton thats a thought as the hose from the primer bulb to the engine and from the bulb to the fitting in the gunnel are orginal and I have not yet replaced them!!!! I will do that tomorrow.

Wes

[LaTriton]

Well I wish that I had read this post before I started working on the boat this evening. I just got through installing a diaphram kit, sqeeze bulb and checking the final filter in the vapor separator. I had a little problem installing the fuel tubes from the schader valve. Got agravated and left it until tomorrow. I am going to run it tomorrow evening.
Would the grey hose have to be replaced all the way back to the gas tank? Sounds like a good idea to change it.

[bluewingjb]

Did you find anything that had failed in your repairs? I am curious as we seem to have the exact same problems.

[LaTriton]

Final filter looked fine. It was a lot of trouble to remove and install the vapor separator. The diaphram did not appear to be worn and you never know about the squeeze bulb. I am considering going to Academy Sporting Goods and buying a sas tank, adding premix and trying to eliminate the fuel tank. I will keep you updated.

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LaTriton &raquo;</TD></TR><TR><TD CLASS="quote">Well I wish that I had read this post before I started working on the boat this evening. I just got through installing a diaphram kit, sqeeze bulb and checking the final filter in the vapor separator. I had a little problem installing the fuel tubes from the schader valve. Got agravated and left it until tomorrow. I am going to run it tomorrow evening.
Would the grey hose have to be replaced all the way back to the gas tank? Sounds like a good idea to change it.</TD></TR></TABLE>

I would highly recommend replacing the hose ALL THE WAY from the tank to the engine.

Make sure you get the NEW DESIGN hose.... it will be gray, with the letters "EPA" (printed in BLUE PRINT) appearing on the hose approximately every 1'

[LaTriton]

Don, I agree with you after this afternoon. I bought a portable tank and went to the Mississippi River in Baton Rouge. I had a 1 gallon can with gas and thought I could use the squeeze bulb to get more gas from the boat tank. When I squeezed it just collapsed and did not squirt much gas. It seemed very spongy. This is a new mercury bulb. I ran it on just the 1 gallon of fuel and it responded well until it ran out of fuel. The bulb squeezed up really hard on the portable tank. I then hooked back up to the main tank and it started acting up again. I was able to reach 63 mph before it quit. I will replace the fuel line. Do you think the anti siphon valve needs replacing also.
Bluewing, I hope this helps and I will let you know if the line fixes it.
Thank you to everyone that responded.

[EuropeanAM]

VERY LIKELY that the anti-siphon valve, fuel line from tank to bulb, or a damaged/block pickup tube is causing your difficulty.