Merc 200 3L Quit Running

[SSGMJones]

Hello...

I have a 2005 Mercury 200 3L EFI (SN 1B042022).

Saturday I started it, put it in gear, and it idled about 10 seconds before it sputtered and died, like it ran out of gas. It would not re-fire, but would crank fine.

Since then i have rebuilt the pulse pump and replaced the bulb and fuel filter/water separator.

The fuel supply hoses looked good (from what i can see peering into the end of the hose) and fuel pumped freely from the hose when i gave the new bulb a few squeezes (making a mess in the process). I pumped up the bulb and it stayed hard after installation.

After rebuilding and reinstalling the pulse pump, i doubted that i had installed two of the gaskets properly. I removed the pump and unlike the first time i removed it, a lot of gas came out of it (after i had pumped up the new bulb)...which made me think that the pulse pump was likely the culprit in the first place.

However, after ensuring the pulse pump was assembled correctly (and pumping the bulb back up), i tried to start the engine and it would still only crank.

Any advice on what to check next? Could it be the VST?

If it ran completely out of gas because the pulse pump wasn't pushing gas to the VST, will the VST need to be bled? Can i pull one of the brass fittings to make sure there's gas in the VST?

This is killing me because this motor has never left me stranded before.

Thanks!

[EuropeanAM]

Do you hear the electric fuel pump cycle for a couple of seconds when you turn the key "on"?

Good idea to get a fuel pressure gauge on it, turn key on and "see" what the pressure is.

Possible for the pump to be bad, debris to have lodged in the float passage, or the float to have "hung" for some reason.

Of course- checking SPARK is also wise (use EXTREME caution around fuel- as any fuel carries with it a risk of Fire or Explosion if a spark is introduced).

[SSGMJones]

Thanks for the reply.

Do i put the gauge on the shrader valve on the front of the VST?

[EuropeanAM]

Yes sir.

[SSGMJones]

Thank you!

I hate to admit it, but i don't recall EVER hearing the electric fuel pump run. (I bought the boat new in 2006. )

I'll report back when i get the fuel pressure tested.

[SSGMJones]

Fished our club tourney last night on the trolling motor and did some on-the-water troubleshooting (and still managed a win somehow!).

There's definitely no noise coming from the electric fuel pump.

When it first died, i checked the kill switch and all the breakers i could find. Everything "appears" normal. There isn't anything else to check that controls power/signal to the pump, is there?

Replacing the pump looks to me to be a fairly straight-forward replacement...remove and open the VST, remove/replace fuel pump, clean all components, and install VST.

Are there any other tricks involved? Any other associated or follow-on tasks that have to be performed?

The more i read into everything, the more it looks like i'd definitely benefit from sending my intake system in for service. Can i PM you, Don, for a quote on what cleaning of the injectors and fuel rail would run?

As always, thanks for the expert advice!

[EuropeanAM]

Please email if you're looking for service or parts estimates/quotes.

It is imperitive that either an oil pump prime be completed (after pump replacement). Failure to do so results in straight gas (no oil).

Test for 12V power and ground at the connector when you first turn the key on. There is an MPR (Main Power Relay) that could potentially be down (and of course, fuses).

[SSGMJones]

It is imperitive that either an oil pump prime be completed (after pump replacement). Failure to do so results in straight gas (no oil).

...either an oil pump prime be completed...or...?

Sorry Sir, just trying to make sure i've got the whole picture. If there's something else that can/should/might also be done, i'm all ears!

Thank you, again!

[EuropeanAM]

Sorry about the "either". Some might look towards using a portable tank of pre-mix, but with this particular system, you can't accurately determine if all of the air is out of the system (thus the importance of performing the complete oil pump prime).

[SSGMJones]

Awesome. Many, many thanks!

I'll be sending an email for more service info.

[lpugh]

I see no mention of checking the fuses?

[SSGMJones]

I see no mention of checking the fuses?

I checked all the breakers under the driver console.

Could you point me toward a possible location of other fuses?

Thanks!

[lpugh]

Starboard side of motor very near computer, probaly has a cover on it and has 4 fuses

[SSGMJones]

Checked fuses near the computer. Two had battery voltage (13.34-ish) and two had minimal...something like 0.3v...with the key on.

Also tested the leads going to the pump. With the multimeter negative lead going to the battery negative, the fuel pump red lead had battery voltage for a few seconds after turning the key on...13.3-ish volts.

The black lead had 0.3 that dwindled to 0.1 in about the same amount of time it took the red lead voltage to drop off.

Is this pointing at an issue somewhere else? I read a little something about the fuel pump controller in the ECU maybe?

Again - Thanks all!

[lpugh]

Using voltmeter check the voltage on both sides of the fuses, if blown one side will not have voltage
res wire to pump should have power all the time with key on, ground side should be near 0 when pump run is requested by the pcm and running. If power on both sides driver has a problem. Depending which system from 2 seconds to 30 seconds. Pretty sure yours should be 2-5 seconds

[SSGMJones]

Ok, cool...so it sounds like i can eliminate any other electrical issues aside from the pump itself being bad or jammed with debris.

The fuses had power on both sides. The testing of the pump connector sounds like what you described.

I'm a diesel mechanic by trade, just not experienced (luckily so far it seems) with in-depth diagnostics on these motors...

[SSGMJones]

Update time...

Replaced the electric fuel pump. Fired up and ran like a champ.

Fished this morning for a few hours. Went to head for the ramp and it did the same thing it did the first time...fired up and acted like it ran out of gas.

What are the chances of two fuel pumps going bad?

I replaced the pump with an OEM Merc pump, PN 881705T1.

Does this possibly point toward a problem somewhere else?

[lpugh]

Have you checked spark to all cylinders while in a no start condition, Fuel pressure at this time
Fuel in the vst?
Sounds as if you disturbed a connection that may have temporally allowed it to start, perform wiggle testing on all the connectors and wiring harness

[EuropeanAM]

Matt- as tempting as it is to jump to what you've just replaced, you MUST go back to the BASICS and treat this as a NEW problem.

Compression, Spark, Fuel System. Also make sure there actually IS liquid fuel supplied to the pulse pump and VST (physically confirm it).

[SSGMJones]

Appears it was the pump connector. Seems I stretched out the socket side during testing.

Also replaced cranking batteries as they were pretty old (5-6 years old) and I hammered them pretty hard during testing and fishing club tourneys off the trolling motor and running livewells, power poles, etc constantly. My partner made the comment that it seemed like it was cranking really slow the last few times i tried to start it.

A huge thank you, again, for all the help. Will update if problems persist.