Turd Polishing

[MrGiggles]

24 minutes ago, fishinwrench said:

Overheat, lack of lubrication, presence of water in fuel, charging voltage exceeding 14.9v, or a bad sensor.

What else? 🤔

What you listed are the only things that should trip a solid alarm. 

The other puzzler is that none of the above should shut it down completely, but limit power to varying degrees, by Mercs "engine guardian" or whatever they call it.

Voltage crossed my mind first, I checked the cables on the battery end on the water and they were fine. It's full of oil and the water pressure was fine. It hasn't spit a rod out of the block, so it must have oil pressure. I'll get a gauge for that eventually to fill the hole in my dash that used to hold the Suzuki monitor.

I think those fuel pumps can cause an alarm too, being that they were just messed with leaves them as a suspect as well.

[fishinwrench]

2 hours ago, MrGiggles said:

 

The other puzzler is that none of the above should shut it down completely, but limit power to varying degrees, by Mercs "engine guardian" or whatever they call it

Water in the fuel will shut her down.  

Is the motor equipped with a "fuel cooler" ?    Some Mercs are so equipped, and a cracked one will contaminate the fuel on the High Pressure side.   Pretty common.   Part of the winterization process includes draining the fuel cooler.  

[MrGiggles]

7 hours ago, fishinwrench said:

Water in the fuel will shut her down.  

Is the motor equipped with a "fuel cooler" ?    Some Mercs are so equipped, and a cracked one will contaminate the fuel on the High Pressure side.   Pretty common.   Part of the winterization process includes draining the fuel cooler.  

It does have a cooling coil and water running through the FSM. It would be easy enough to loop them and bypass the cooler for testing purposes.

[MrGiggles]

Found part of my fuel supply issues. That is the pickup straw in the tank, kinked almost shut. Looks like the top of the tank has warped a little bit with age, so the pickup was touching the bottom.

I didn't have any submersible line that size, so I just shoved a piece of copper tubing inside of it so it can't kink and put it back together. I also did away with the quick coupler on the tank.

I had it out again yesterday, had the same troubles. When it quit on me the primer bulb was totally empty.

I did some more reading, since the ECM controls both fuel pumps, if it sees that the lift pump has ran for too long and hasn't tripped the float switch, it will set a code and alarm, same goes if the lift pump circuit is open or shorted. I suspect that is where my alarms are coming from, we'll find out pretty soon once my Vessel view dongle shows up.

[fishinwrench]

You can do a siphon test to make sure there are no fuel delivery issues.    

Just get the fuel supply hose lower than the tank, prime it, and see if fuel continues to freely flow for a 1/2 gallon or so.     

Some tanks are equipped with an anti-siphon valve.....but as long as the tank is lower than the motor you can remove it.   Anti-siphon valves are only needed on pontoons, or applications where the fuel tank is above the motor.

[MrGiggles]

3 hours ago, fishinwrench said:

You can do a siphon test to make sure there are no fuel delivery issues.    

Just get the fuel supply hose lower than the tank, prime it, and see if fuel continues to freely flow for a 1/2 gallon or so.     

Some tanks are equipped with an anti-siphon valve.....but as long as the tank is lower than the motor you can remove it.   Anti-siphon valves are only needed on pontoons, or applications where the fuel tank is above the motor.

I would've liked to have known that about 6 months ago. Had a lot of the same trouble with the Suzuki too, some days it was fine, on others it would take forever to pick up fuel on its own. 

I always heard that a fuel restriction would suck the primer flat. Is that true? A lot of primers are pretty stiff, I'm not sure that little pump has enough gusto to collapse it.

[fishinwrench]

A near total blockage can suck the bulb flat.....if the blockage is between the bulb and the bottom of the pickup tube.   

The most common damage caused by a pinched or blocked fuel supply line is a ruptured or overly stretched fuel pump diaphragm.    A floppy/overstretched diaphragm that isn't forced completely tight by the spring/plunger can't properly do its job.  

[MrGiggles]

I guess it's time for an update. Last trip to the lake was the same result. Worst part is that it will run fine until you get to the spot and throw a fit coming home. Vesselview shows codes for the vent switch, purge valve, and float switch. Vent switch code is from me priming it and overflowing the FSM, the purge valve code is there from when I unplugged it while the motor was running to clear the vent valve.

The float switch code is likely a timeout error (code sets when lift pump has ran for X amount of time and float switch still hasn't closed, indicating the FSM is full) but Vesselview doesn't really elaborate, and Mercury apparently hasn't published a list for VV codes, which is extremely aggravating since they don't correlate to anything else. It's basically a "call dealer for more" type of deal. I have tested the float switch and it works perfectly.

It'll pass the siphon test with flying colors. 

I removed everything, filters, primer, all of it from the suction hose. Stuck just the hose right onto the pump tube. Still nothing, pump won't pull fuel out of the tank unassisted.

The seal between the FSM body and lift pump is in great shape. The pump is not wired backwards. The pumps have different connectors so they cannot be mixed up. There is no reason for it to not be sucking fuel except if the pump is no good. There isn't even the tiniest bit of suction on the lift pump inlet. All signs pointing to the pump, even though it is new.

 

[fishinwrench]

Is the lift pump a mechanical diaphragm pump?  

Have you tried bypassing the fuel quick-connect fitting.....if so equipped ?    They are prone to leak, and can easily become clogged.  

[MrGiggles]

4 hours ago, fishinwrench said:

Is the lift pump a mechanical diaphragm pump?  

Have you tried bypassing the fuel quick-connect fitting.....if so equipped ?    They are prone to leak, and can easily become clogged.  

It's electric.

I tossed the quick connector on the tank a couple weeks ago. There is nothing but a bare rubber hose between the pump and the tank pickup.