2003 21i died on the water today

[chpthril]

19 looks like a vacuum line, so 13 appears to be a pressure regulator.

[TeamAllen]

If you need or want a spare fuel pump, a guy figured out a generic and less expensive replacement. It allows you to replace just the pump rather than the entire cooler assembly from Mercruiser.
http://forums.iboats.com/mercruiser-...es-417561.html

[boatwakes]

13 is the pressure regulator but you could potentially be dealing with a stuck open injector too or a fuel restriction to the pump. DON'T RUN WATER THROUGH THE PUMP. Hook up an external fuel tank and see if it'll run off that, if so, look for the anti-siphon valve to be bad. If not, replace the pump and regulator and try again. Get a fuel pressure gauge too, gotta know what you're starting with.

[huntingwiley]

I have an 03 21i and have experienced this twice. Went through all the fule system checks the first time to find it was the IAC (Idle Air control valve) causing this issue. The second time 3 yrs later when it happened I just replaced the IAC and solved the issue. I would look at them before buying a fuel pump. It only 100$ roughly if that is it. It is located on the top of the engine right behind the fire arrest-or. The Mer 350 MAG MPI is know for going through these things.

[chuckhoenig]

Here is the update.

Put the fuel pump etc back together.
Tested pressure. 40psi
Ran main fuel line into a can of new gas
Started right up and ran.
Started again, revved it to 4000rpm a few times sounded great
Put fuel line back together, to include an inline fuel filter
Started again ran at idle lost pressure down to 10psi and died.
Put fuel line back in gas can and still won't stay running. Pressure is at 10psi
Now the pressure is stuck at 10 and won't come up.
I can still hear pump going but pressure is not going up.
Btw way, I actually have two pumps the other is on the starboard side of the boat. It is also getting power and seems to be running fine.

[chuckhoenig]

I stopped by the marina and spoke to their mechanic. He thinks it is either the high or lower pressure pump. More than likely the low pressure because it is whining. He said the best way to check if it is the low or the high is the put a Schrader valve between the two pumps and check the pressure. if you don't have pressure on the between the two, and no pressure on the rail, then your low pressure is bad. If you do have pressure on the low, but not the high, then your high is out.

Chuck

[chuckhoenig]

OK. I changed the low pressure pump and the cooler. Pressure still not coming up. Switched to a separate gas can to rule out the anti-siphon valve. Stuck at 10. I did get it to come up some after messing with the IAC valve. Came up to 35, then started and ran, but ended up falling back down and stalling. Can the IAC Valve have an effect on the pressure in the fuel system?

Chuck

[chpthril]

no

[chuckhoenig]

Ok, went back over to the boat (I'm a little obsessive), checked my connections and I'm holding pressure at 40psi. Started it, ran it for a few minutes dropped to 35 but was steady as a rock. Ran some more no drop.

2 Questions:
1. could I have been sucking air from loose connections?
2. My high pressure pump, is much hotter than my newly installed pump. My mechanic told me it could be that the other pump is bad, and is running hot because it is struggling. Thoughts?

Thanks,
chuck

[boatwakes]

When the low pressure pump fails, here are the symptoms:
- Engine will fluctuate between 3300-and 2600 without moving the throttle, in gear under load ONLY, in neutral revving up is no load situation.
That's it, no other symptoms. So you need a new high pressure pump and the reason is it's struggling because you bench tested it with water. Water kills electric fuel pumps. Replace the pressure regulator too, small pieces of crap and ethanol and bad gas just say do it.
The IAC shows its head when the boat won't start or idle but will run if you give it enough throttle to open the plate past the IAC input.
$45 from auto zone for a ford aerostar.

[chuckhoenig]

Ok, I think I have my pumps mixed up.

I pulled my pump attached to my cooler and bench tested that one with water. I replaced that pump and the fuel cooler yesterday ($400).

Do you think my second pump by my fuel separator is bad too? I never removed it or bench tested it. It is getting power, I chedcked the connection it's pulling 12 volts.

Thanks,
Chuck

[boatwakes]

Didi you ever change the pressure regulator? The booster pump/low pressure pump by the filter again will only present with surging engine rpm under load, but the pressure regulator on the high pressure pump is responsible for getting the rail pressure correct. The high pressure pumps will produce in excess of 100psi unregulated but if the regulator is sticking they'll be all over the map which is what you're describing.

[chuckhoenig]

I didn't, do you know the part number?

[ghunt6]

.

[boatwakes]

Go to perfprotech.com and use your engine serial number to locate it on the diagram.