No Gas to Carb

Engine is 1996 VP 5.0FLPNCS. 2 bbl Holley. Looking down the carb I don't see any gas going in. Pulled the lines to the carb from the filter and it was clear. Pulled thde line from the filter to the pump and it was clear. The connection on the gas tank had some rust so I thought it was a bad connection but no help. Is the fuel pump the only thing left which I should replace or maybe something electrical. Desperate for help. I shopuld also say that my son took it out the other day and it ran ok for a while and then upon a restart it wouldn't start. As always, thanks for your help in advance.

Re: No Gas to Carb

Your questions confuse me a bit.

When "looking down the carb" you should see nothing but air and fuel vapor...which is essentially invisible. You should not see fuel. This is entirely normal, whether engine is cranking, running, or sitting there shut off. The fuel itself is inside the float bowls hidden from view. You can't see liquid fuel in a carb without opening up the float bowls.

The only time you would see a shot of fuel going in by looking down the air horn is the moment you pump the accellerator...at that moment you should see a quick primer shot of liquid fuel (no need to crank engine or have the ignition on or anything...just pump the gas while looking down the carb). Of course this assumes there is fuel in your float bowl, and your accellerator pump within the carb is functioning properly.

You have a mechanical fuel pump, so if fuel is indeed not reaching your carb, it would absolutley not be the result of an electrical problem.

Quick summary of how to test a mechanical fuel pump...1. disconnect fuel line at carb, put the end in a container to catch fuel. 2. Crank the engine. Fuel will squirt out if the fuel pump is working...and if there are no fuel delivery problems between the tank and the pump. Take fire hazard precautions...disable ignition/etc before doing this.

If fuel does not squirt out when you do this, it still does NOT necessarily mean your fuel pump is the problem. This link shows good methods of how to properly test the remainder of the boat's fuel delivery system before the fuel reaches the pump:
http://forums.iboats.com/showthread.php?t=283269

Are you 100% certain you have a fuel delivery problem? Or do you simply have a no-start problem and are guessing that it is a fuel delivery problem?

Do not blindly replace parts...way too expensive. Troubleshoot, diagnose, and determine the problem first, THEN replace the necessary part if it actually needs to be replaced...

Re: No Gas to Carb

Thanks for the come back. I assumed you, the reader, would figure I was pumping the gas to see it squirt inside the carb but nothing. I pulled off the pick up and it was clean. Removded the line from the pump to the carb, blew it out and it was clean. Also removed the line from the filter to the pump and same thing. I also did what you suggested about removing the line at the carb, gave it a crank and no gas. Does that now mean the only thing left is the pump? Again, thanks for your response. PS - I just read the link you suggested and it makes sense except right now I can't get it started so I think fuel pump in light of all things done so far. You agree?

Re: No Gas to Carb

LOL. I assume nothing....

sethjon said:

PS - I just read the link you suggested and it makes sense except right now I can't get it started so I think fuel pump in light of all things done so far. You agree?

Click to expand...

Maybe. You can price the pump and decide for yourself whether you want to guess by replacing it, which it may or may not need, and may or may not fix the problem. If it is inexpensive it might be worthy of trying.

If it is too expensive for you to feel comfortable guessing with, then you need to first determine whether you have other problems somewhere in the fuel tank/lines/filter/water separator/check valve/etc. Any of those items could be causing a problem by not being able to supply fuel to a fuel pump that may be fine.

You might be able to use a separate gas can to see if the fuel pump can generate enough vacuum to suck fuel. Put a known clear inlet line direct from the fuel pump into a can of gas and crank the motor. This removes the entire boat fuel tank system variables. If it can't suck unfiltered fuel directly out of the fuel can while being cranked, the pump is confirmed bad.

Have you replaced water separator filter? Is the fuel in the tank known to be new/good/water free/no phase separation? Is it possible the pickup line inside the fuel tank has a leak?

If you are 100% confident that all of above are in good shape, then indeed the fuel pump likely needs to be replaced. But I suggest testing it first...without using the remainder of the boat's fuel system.

Re: No Gas to Carb

You can test the fuel pump with a vacuum gauge. Beats wondering about it. You can test it while on the engine, but may need to test it on the bench also, as the problem may be the cam eccentric has gone flat and is not pushing the lever as far as it used to.

Re: No Gas to Carb

I'm assuming we're talking about a mechanical pump here...if so and the pump has been dry for a while you may be able to prime it with fuel using a short length of clear line from a portable fuel container filled with fuel. I had to do this today on my older AQ131A Volvo engine. The pump would not pull fuel from the tank or another container, but once I primed it (filled clear line with fuel and then elevated the line allowing gravity to feed the pump while cranking the engine) it was able to pull fuel without issue.

Re: No Gas to Carb

Didn't think of that except that my son took it out the other day and ran for a short time. Also, I didn't think there was suposed to be any gas in the clear line unless there was a problem in which case the extra gas gets dumped into the carb rather than the bilge.

Re: No Gas to Carb

If the cam got flat, how is it replaced?

Re: No Gas to Carb

Replaced the pump today and thought all would be good. No luck. Added gas directly to the carb and it started for about 10-15 seconds. The last thing I tried was loosening the nut on the fuel line at the carb and I did see some leaking so I figure the pump is doing its job. So why doesn't it stay started? Could it be the carb?

Re: No Gas to Carb

Hook up a remote fuel tank to the fuel pump, then put some gas in the carb and see if it runs. I seriously doubt the cam is bad. Fuel pump installed wrong maybe, but not a bad cam at this point.

Re: No Gas to Carb

As usual, thanks for the come back Don. I woke up at 3:30 this morning having dreams about this boat. Waited for day light and pulled the pick up.... AGAIN. After dstaring at it for a while I realized it wasn't wet so I pulled the sending unit, stuck a ruler in the tank and decided it was way too low on gas. Added 6 gallons and it start and ALMOST all is well. Last week I installed a new impeller since my son just got this boat. Now I see a very SMALL leak as it runs. Is it supposed to do that? The leak is not at hose connection or where the 2 halves join with the new gasket. Its closer to the forward side. As I say, the leak is only a drip drip. what do you think? Have a great weekend!!

Re: No Gas to Carb

sethjon said:

so I pulled the sending unit, stuck a ruler in the tank and decided it was way too low on gas.

Click to expand...

"I, the reader" am chastised for not ASSUMING that you knew you had to to pump the throttle to "see" gas in the carb....and I defend myself by saying "I assume nothing..." only to discover that I DID assume you actually checked that there was FUEL in the tank!

100% my fault I guess...for assuming you had fuel in the tank before asking fuel pump questions....

My salt-rubbing is all in good fun....please don't take it badly. I have certainly done silly similar things in my past as well. LOL! I'm genuinely glad you got it going...and now you have an extra fuel pump for your inventory. Chalk it up to experience. Test, diganose, and only THEN replace...

Now on to your water leak problem. For fear of assuming ANYTHING...are you asking about the impeller in the water pump on the front of a freshwater cooled engine?? And when you say it's dripping water, it is dripping water inside the engine compartment at the front of the engine?

If yes to both accounts, then you are suffering a very common Volvo failure. Your seawater pump assembly is bad. No drip is normal. And that dripping water is traveling directly thru your water pump bearings before hitting your bilge, and these bearings have therefore been completely washed of their lubricant, and now they are badly rusted. With time the dripping will get much worse, and eventually the bearings will seize. If you run in salt water, the spray in your engine compartment can REALLY wreak havoc...FAST.

Replace the entire seawater pump assembly and your leak will be gone. FWIW the pump assy will come with another brand new impeller pre-installed...so you didn't need to buy the impeller you've already installed...

Here's another post on the same forum page as this one, discussing the same typical Volvo water leak problem:
http://forums.iboats.com/showthread.php?t=540929