2014 225 ProXS stumble / stall when cold

didn’t get a duel gauge set yet but i did throw a standard pressure gauge on the fuel side just to see what my key in pressure was and if it bled off. sooo… key on i only see 10psi. if i cycle the key again it’ll jump to around 20 and then bleed off to 10 again. if i cycle it a couple times quickly it’ll jump 10psi each time the pump runs finally getting to 40 but as soon as you don’t cycle the key it drops right off to 10-12psi. what am i suppose to be seeing and what might this be because im pretty sure thats was to low.

went on my trip last week and engine ran fine except for the cold start and stall in gear thing. still if fire it up and let it idle for 1-2 mins no issues whatsoever. is there a regulator that is letting it blow off the pressure to early or a bad pump maybe.

did you pump bulb before each test , what is fuel psi while its running , what happens to pressure at key off after engine dies , does it drop then hold or continue to drop , it does have regulator and fuel psi is dependent on air pressure to build useable pressure for the system

i did not get it while running. i just picked up a gauge to see what it does when key on which i believe it not normal for what im seeing. to see it stall and check pressure i need to run that check on the water and just haven’t been out to the lake yet.

:thumb up2:

I just picked up a mercury factory service manual so I’d have everything I need information wise. However, looking through some stuff, the mercury manual says that the throttle plate air gap should be .075 not .093. Was there an update somewhere along the line that this manual doesn’t have? Very curious about this one because according to this manual, my bottle plate gap was adjusted pretty much accordingly.

Use the .093 spec

i also am wondering about the air pressure reg diaphragm and the orientation of that center section that is half moon on one side and flat on the other. i believe it was said in a previous post that the flat side is to face the rail and be the seating surface. however if i’m looking at this correctly in the manual. it’s showing the half moon side facing the rail. can anyone clear up what i’m seeing here?

Made up a gauge set to check pressure. here’s what i got

LOW (at VST)27psi running / 15psi key on and 15psi within a few seconds after engine shuts off

HIGH (rail) 107-108psi - 94psi after 6 mins engine off

AIR 93psi-94psi

The pressures are all good.

Quote:

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Originally Posted by NJfishinGuy

Made up a gauge set to check pressure. here’s what i got

LOW (at VST)27psi running / 15psi key on and 15psi within a few seconds after engine shuts off

HIGH (rail) 107-108psi - 94psi after 6 mins engine off

AIR 93psi-94psi

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those readings are to vague for accurate diagnoses, using your numbers it is possible you could have as low as 13 psi spread between fuel and air, if you have 13 psi spread it could very cause poor run cold or far worse, needs about a 14.7
also reverse the hooks to verify both gauges read exactly the same

Quote:

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Originally Posted by NJfishinGuy

Made up a gauge set to check pressure. here’s what i got

LOW (at VST)27psi running / 15psi key on and 15psi within a few seconds after engine shuts off

HIGH (rail) 107-108psi - 94psi after 6 mins engine off

AIR 93psi-94psi

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Reading through the tea leaves If:

Fuel 108 Air 94 equals Good
Fuel 107 Air 93 Still Good
Low fuel pressure while running 27 PSI Good

Not sure what you are referring to with the 15 PSI

savage, what i meant was with a gauge on the low side port. on the vst. the fuel pressure when you just turn the key in to cycle the pump is about 15psi. when the engine starts that comes up to the 25-27psi and when you shut the engine down that immediately drops off to the 15psi again.

That's normal.

For future reference, please try to spec your readings AIR/FUEL.

For best accuracy:

-At idle

-Under Acceleration (preferably at 1000 RPM's)

-5/10/15 seconds after engine shutdown (restart for each period).

Must be able to read BOTH at the SAME TIME on glycerin-dampened gauges, of course.