No fuel coming from fuel pump.

[gpolkin]

I just rebuilt the Rochester carb on my 77 merc 140. This was prompted due to some hesitation when I was accelerating. Ran smooth and would eventually get on plane if I eased it up slowly. I also replaced my fuel pump filter.

I just attempted a post rebuild initial start-up. I was getting no fuel to carb, I verified this by disconnecting fuel line first at the carb and later at the pump and cranking. The canister filter was changed recently and I just put 5 gallons of gas in the tank.

Tomorrow I am planning on trying to run with fuel pump intake hose directly in a gas can to rule out a clogged canister filter. Any other ideas? Is there something I need to do to prime fuel pump post filter change?

Thanks in advance for you advice.

Greg

 

[gpolkin]

Re: No fuel coming from fuel pump.

I just rebuilt the Rochester carb on my 77 merc 140. This was prompted due to some hesitation when I was accelerating. Ran smooth and would eventually get on plane if I eased it up slowly. I also replaced my fuel pump filter.

I just attempted a post rebuild initial start-up. I was getting no fuel to carb, I verified this by disconnecting fuel line first at the carb and later at the pump and cranking. The canister filter was changed recently and I just put 5 gallons of gas in the tank.

Tomorrow I am planning on trying to run with fuel pump intake hose directly in a gas can to rule out a clogged canister filter. Any other ideas? Is there something I need to do to prime fuel pump post filter change?

Thanks in advance for you advice.

Greg

One other additional piece of info.... I just checked the new yellow tube that I also just installed that goes from the fuel pump to the carb. The lower inch of it had a black color. When I blew it out with compressed air it had a sticky texture.

 

[dingdongs]

Re: No fuel coming from fuel pump.

there is a rubber diaphragm inside and it may have split and will require replacing.best to just remove the pump directly and try manually pumping as you can see easily if its not pumping.2 bolts and its off.a lobe on the camshaft is what normally activates it giving the pumping action.make sure the prefilter is not blocked too.

 

[EddiePetty]

Re: No fuel coming from fuel pump.

....by chance did you install the fuel pump filter upside down?

 

[gpolkin]

Re: No fuel coming from fuel pump.

....by chance did you install the fuel pump filter upside down?

It is installed with the filter above the pump. It was previously in this orientation and this is the only way the outlet lines up with the steel fuel line. Pretty sure this is right.

The manual I could find has a very similar pump but installed filter bowl down. It says that the diaphragm cannot be repaired/replaced. Anyone repair one of these? Where do you get rebuild kits?



Thanks for weighing in.

Greg

 

[Silly Seville]

Re: No fuel coming from fuel pump.

....by chance did you install the fuel pump filter upside down?

It is installed with the filter above the pump. It was previously in this orientation and this is the only way the outlet lines up with the steel fuel line. Pretty sure this is right.

The manual I could find has a very similar pump but installed filter bowl down. It says that the diaphragm cannot be repaired/replaced. Anyone repair one of these? Where do you get rebuild kits?

What he meant was...did you install the filter element upside down in the fuel pump bowl? That would slow or block fuel flow.

The filter bowl down version was an improvement over the former "up" design. I can tell you with 100% certainty, you can replace the diaphragm. I went right to a Sea Ray dealer, told them what I was working on, and he handed me the rebuild kit for it! $44 bucks and worked perfectly. If I still had the box the kit came in I would give you the part number. Or you can just goo-gal for the info, or contact your local, friendly marine dealer. Good luck!

 

[EddiePetty]

Re: No fuel coming from fuel pump.

What he meant was...did you install the filter element upside down in the fuel pump bowl? That would slow or block fuel flow.

Silly Seville understood me!

Let me try again: The fuel filter within the pump must be installed with the open end resting on the gasket.
The filter element within the carb must be installed with the open end facing the inlet fuel line and the closed end resting on the spring in the bore of the upper half of the carb.

Additionally, you mentioned replacing the 'canister' filter......if you are referring to an inline water separator, unless you pre-filled the filter (especially with a dry carb), you will crank three days to forever trying to get fuel to the pump/carb.

 

[EddiePetty]

Re: No fuel coming from fuel pump.

One other additional piece of info.... I just checked the new yellow tube that I also just installed that goes from the fuel pump to the carb. The lower inch of it had a black color. When I blew it out with compressed air it had a sticky texture.

No worries there!

Just normal accumulation of oil mist/film from the diaphragm doing its thing. Worry when you see liquid fuel in that line....an indication that the diaphragm has ruptured requiring fuel pump rebuild/replacement.

 

[gpolkin]

Re: No fuel coming from fuel pump.

No worries there!

Just normal accumulation of oil mist/film from the diaphragm doing its thing. Worry when you see liquid fuel in that line....an indication that the diaphragm has ruptured requiring fuel pump rebuild/replacement.

Thanks for the info guys.

Good to know a little black debrie in the site line does not mean the pump is toast. I have the open end of the filter on the gasket and closed end against the spring at the end of cone bowl.

I also heard that there can be a backflow valve at the fuel tank outlet that can get stuck. I will check that too.

So my plan is:
1) Check the fuel tank outlet line.
2) Try to run the pump with it's intake hose directly in a gas can.
3) Maybe try to prime the pump if I can.
4) Fill the canister fuel separator with fuel. Try again
5) If all that fails then go try to buy a rebuild kit and look for a video/manual that shows me what to do.

Greg

 

[gpolkin]

Re: No fuel coming from fuel pump.

Thanks for the info guys.

Good to know a little black debrie in the site line does not mean the pump is toast. I have the open end of the filter on the gasket and closed end against the spring at the end of cone bowl.

I also heard that there can be a backflow valve at the fuel tank outlet that can get stuck. I will check that too.

So my plan is:
1) Check the fuel tank outlet line.
2) Try to run the pump with it's intake hose directly in a gas can.
3) Maybe try to prime the pump if I can.
4) Fill the canister fuel separator with fuel. Try again
5) If all that fails then go try to buy a rebuild kit and look for a video/manual that shows me what to do.

Greg

Just started up in the driveway and seems to be running smooth. I think the key was feeding the fuel pump gas directly from a can above it so it could easily prime. The water separating canister was full when I checked it.

Thanks again for all your help. If the wind and rain die down I hope to drop it in the lake later for a real test drive.

Greg

 

[EddiePetty]

Re: No fuel coming from fuel pump.

So.......your base problem was most likely a dry, rebuilt carb and an empty water separator.

You can get away with one or the other but not both! Next time ensure that the carb bowl is full when changing the water separator or the separator is full when repairing the carb. Your battery and starter will appreciate it.

Glad you got 'er running.