Logo
FULL SITE MENU

Fuel pump flow rate

H

Hutchy

New member
I could use some help in diagnosing my ‘19 Merc pro kicker, 4 stroke (carb), serial OR664339. When I took it out of storage it didn’t want to start. Noticed the primer ball wasn’t keeping its prime, started looking along the system and noticed there was a split in the line at the carb~ repaired. Still didn’t want to start..Noticed fuel was leaking from my carburetor (around that plunger plate thingy) Purchased a carb kit (I can’t believe they’re that expensive ffs) cleaned and rebuilt carb (some of the O-rings were deteriorated); leak stopped, but still won’t start. Remove the plugs and sprayed dome fuel in the cylinders and it fired and wanted to start. I should mention spark was confirmed prior to all this. So now I want to narrow it down to either the fuel pump or carburetor; but with a price tag of $280 for a stupid pump, I’m not gonna just replace it as a shot in the dark hunch. Does anyone know what the fuel rate is on these pumps? And what that plunger does on the carb? Shop rate here is like $180/hour 🙄

Thanks in advance
 
Welcome to the world of expensive boating with 4 strokes.------The fuel pump has nothing to do with starting of the motor.----Set the idea of a new pump aside. for now.-----Do you run motor dry / empty the carburetor during storage ?----A cleaning of wee jets may be needed.-----You do not always need a kit on these.------Remove sparkplugs.-----Put 6 drops of fuel in each hole.----Install plugs.-----Try to start motor.-----Report exactly as to what happens.
 
racerone said:
Welcome to the world of expensive boating with 4 strokes.------The fuel pump has nothing to do with starting of the motor.----Set the idea of a new pump aside. for now.-----Do you run motor dry / empty the carburetor during storage ?----A cleaning of wee jets may be needed.-----You do not always need a kit on these.------Remove sparkplugs.-----Put 6 drops of fuel in each hole.----Install plugs.-----Try to start motor.-----Report exactly as to what happens.
Click to expand...
I do run system dry for winter storage and only run 91 octane. When replacing the internal o rings, in the carburetor, I also disassembled everything and gave it a good soak and cleaning. All orifices are clear. When fuel is sprayed into the chambers, the motor wants to start, but with no fuel coming in, it quickly dies. I’ll try again
 
Hutchy said:
I do run system dry for winter storage and only run 91 octane. When replacing the internal o rings, in the carburetor, I also disassembled everything and gave it a good soak and cleaning. All orifices are clear. When fuel is sprayed into the chambers, the motor wants to start, but with no fuel coming in, it quickly dies. I’ll try again
Click to expand...

racerone said:
Welcome to the world of expensive boating with 4 strokes.------The fuel pump has nothing to do with starting of the motor.----Set the idea of a new pump aside. for now.-----Do you run motor dry / empty the carburetor during storage ?----A cleaning of wee jets may be needed.-----You do not always need a kit on these.------Remove sparkplugs.-----Put 6 drops of fuel in each hole.----Install plugs.-----Try to start motor.-----Report exactly as to what happens.
Click to expand...
 
It won’t let me upload any videos, even an 8 second clip is “too large”. I went to measure the flow rate afterwards and when I removed the line feeding the carburetor and put it in a bottle, it wouldn’t stop flowing (despite not cranking) just static draw? So does that mean the pump is purely to generate pressure? And the issue lies somewhere in the carburetor? The only thing that wasn’t serviced was thst plunger; because it was an additional $70 fkn dollars! 🙄😩 The diaphragm looks fine, unless it’s stretched/fatigued?
 
I took the pump apart today, to inspect and make sure there wasn’t a torn diaphragm or something obstructing the flapper; everything was clean and looked good. There was some oil on the plunger side of the diaphragm though. Is that normal?
 
Back
Top