Mercruiser 3.0 Fuel Issues

[cubajorge_2008]

Electric choke, Loosen the cap on the choke, move it open one notch, tighten cover. Test the results.

I try the choke and choke is no problem. What i did notice and i do not know if thats normal. I added an extra fuel filter from tank to pump. At first it pumps fine. Then the fuel filter empty completely. I remove the hose from the tank and i do not fill it sucking. Is it suppose to suck constantly or only as needed?

 

[cubajorge_2008]

What im trying to say is that it pump but doesnt suck the gas up all the time. Is that normal? It sucks intermentently if no presure is found. Menaing if i disconnect it from the carb it sicks and pump. But when i connected it again eventually it stops sucking

 

[alldodge]

A mechanical pump doesn't have much suction. Also pumps are mounted at or below fuel tank exit fitting

What kind of pump is in pic?
What is the other item?

 

[QBhoy]

View attachment 353695
Before you guys said anything Im using a fuel regulator but only until i get the fuel pump
Original gasket that should arrive next week wednesday. The after market fuel pump seems to pump to much pressure around 9psi. Moreover, as you can see on the pic the clear fuel filter is half full and it happens everytime on start up. Causing my start up to be rough and longer to warm up

That filter, Is it flowing in the right direction ? Regardless, you don’t want it there anyway. I’d also say that they never show fully filled with fuel either.

 

[cubajorge_2008]

A mechanical pump doesn't have much suction. Also pumps are mounted at or below fuel tank exit fitting

What kind of pump is in pic?
What is the other item?

View attachment 353744

The thing that looks like a pump is a fuel regulator. I was testing because the old pump i had was pumping 10psi . And the other thing is the timing light lol. I left it there i was setting the timing

 

[cubajorge_2008]

That filter, Is it flowing in the right direction ? Regardless, you don’t want it there anyway. I’d also say that they never show fully filled with fuel either.

It fills up and hold full vut when ever i start it from cold again it empties and on the second pic is a clear filter from tank to pump. To see if it hold full or stays empty, and it does get empty enventually. I disconnected the line from tank put my finger and it does suck . But it will start sucking if i remove the hose from the Carb instead. I guess when it detects pressure it stops sucking??

 

[alldodge]

The thing that looks like a pump is a fuel regulator. I was testing because the old pump i had was pumping 10psi . And the other thing is the timing light lol. I left it there i was setting the timing

Good deal
If you have a regular marine fuel pump which is motor driven off the side of the block, would like to know which one. Don't remember if you gave us your serial number, but some pumps need 2 gaskets to keep the pressure down to 7 psi or less

With it emptying, need the pump type model number and does the tank have an antisiphon valve

 

[cubajorge_2008]

And another thing a learned my fuel tank didnt have a fuel pickup tube? Just the upper part. Is that normal? Or does it need the tube?

 

[alldodge]

And another thing a learned my fuel tank didnt have a fuel pickup tube? Just the upper part. Is that normal? Or does it need the tube?

Need clarification
There needs to be a tube that goes down to the bottom of the fuel tank. If the fitting is removed and there is no tube, then check the tube is not part of the tank. If there is no tube which goes to the bottom of the tank then that is a problem

Antisiphon valve

 

[poconojoe]

And another thing a learned my fuel tank didnt have a fuel pickup tube? Just the upper part. Is that normal? Or does it need the tube?

Doesn't it need a submerged pickup tube to extract the fuel?
How can it pick up fuel without one?
Or maybe I just don't know what I'm talking about....

 

[alldodge]

There has to be one

 

[cubajorge_2008]

Good deal
If you have a regular marine fuel pump which is motor driven off the side of the block, would like to know which one. Don't remember if you gave us your serial number, but some pumps need 2 gaskets to keep the pressure down to 7 psi or less

With it emptying, need the pump type model number and does the tank have an antisiphon valve

You need the engine serial? Or pump

Need clarification
There needs to be a tube that goes down to the bottom of the fuel tank. If the fitting is removed and there is no tube, then check the tube is not part of the tank. If there is no tube which goes to the bottom of the tank then that is a problem

Antisiphon valve

Oops looks like the tube is part of the tank

 

[cubajorge_2008]

There has to be one

Turn out there is one and is part of the tank

 

[poconojoe]

There has to be one

Maybe there is a pickup tube and it is cracked and is intermittently sucking air.

What is the function of the anti-siphon check valve? To prevent the fuel from flowing back to the tank? If so, maybe it is defective and gravity is causing the fuel to flow back to the tank.

 

[cubajorge_2008]

This is the pump i bought off amazon
Fudoray Bomba de combustible mecánica para motores Mercruiser 120 140 165 180 181 170 190 225 470-1 488 OMC Volvo Penta 181 2.5 3.7 L sustituye a motores 3854858 42725A3 509407 3333333382 9-35422 8M0073435 861676A1 https://www.amazon.com/dp/B07ZSZTT1...abc_AVKFNMMHF9WNP224JBDW?_encoding=UTF8&psc=1

 

[alldodge]

What is the function of the anti-siphon check valve? To prevent the fuel from flowing back to the tank? If so, maybe it is defective and gravity is causing the fuel to flow back to the tank.

It has 2 functions but the first iss for safety. It keeps fuel from being able to siphon fuel from the tank if a fuel line breaks. The other side it should keep fuel from going back to the tank, but then again the fuel pup should help in that effort

 

[alldodge]

This is the pump i bought off amazon
Fudoray Bomba de combustible mecánica para motores Mercruiser 120 140 165 180 181 170 190 225 470-1 488 OMC Volvo Penta 181 2.5 3.7 L sustituye a motores 3854858 42725A3 509407 3333333382 9-35422 8M0073435 861676A1 https://www.amazon.com/dp/B07ZSZTT1...abc_AVKFNMMHF9WNP224JBDW?_encoding=UTF8&psc=1

Good marine fuel pump
Need to match up with your motor because it should not be pumping more pressure

What pressure are you seeing?

 

[cubajorge_2008]

Good marine fuel pump
Need to match up with your motor because it should not be pumping more pressure

What pressure are you seeing?

With the fuel regulator 5psi without it 9psi

 

[poconojoe]

It has 2 functions but the first iss for safety. It keeps fuel from being able to siphon fuel from the tank if a fuel line breaks. The other side it should keep fuel from going back to the tank, but then again the fuel pup should help in that effort

Thanks for the explanation!

 

[alldodge]

Either pump is defective or its the wrong pump.
What's your serial number?

With the fuel regulator 5psi without it 9psi