Volvo Penta 4.3 No Gas Getting to CARB!!!!

[MIKESANDO]

I have a 1996 Volvo Penta 4.3 w/ a holley 2bbl carb on it. Last week took the boat out and ran it for about 4 hours. Ran perfect. Thursday took it back out and would not start. After several hours of trouble shooting it I found out that there is absolutely no gas getting to the carburetor. Thinking it was a clog I started at the gas tank and worked my way up to the carb. Checked all lines for cracks, and checked for any interference in the lines, but there were none. I am getting power to the fuel pump when turning it over I also noticed that the accelerator pump is not priming at all. I have to pour gas in the top of the carb for it to fire, but it only burns the fuel off then stalls!!! I bought a new fuel filter but no help.

When I was looking for clogs in the line I tried to blow thru the fuel pump and it is very hard to do so. Is this normal?
what could cause my carb bowl to become empty? I do not smell or see any gas leaks after I pour it down the throat of the carb? I would have thought that after I prime it and it started the motor that the fuel pump would then pull gas into the carb? But I do not think that is happening? Any ideas I am absolutely stumped!! Thanks very much for any replys in advance.

Thanks again
Frustrated boat owner

 

[CheapboatKev]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

Welcome Aboard!





What I would do..

Disconnect the fuel line at the carb and have someone turn the motor over..

Does gas squirt from there? if so you are getting fuel up to the carb.

If not, I would get a gerry can of new fuel and put the line from the boats fuel tank into the can and see if it draws fuel to eliminate the fuel pump.

Sounds like you have an electrical fuel pump..If so I think they are wired to the oil pressure sending unit on the motor..May want to look there as well.


Good luck and others far smarter than I will be by to help.

 

[Jeepster04]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

First things first, check to make sure the fuel pump is pumping. Sounds like theres a very good possibility its not. You say youre getting power to the pump but can you hear it running?

Do like kev said and run a line from a can of gas to the fuel pump and see what happens.

Keep the blower running while youre working with all of that gas. Use common sense too..

 

[MIKESANDO]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

Thanks for the quick response...i did disconnect the line that leads to the carb and try to turn it over but no gas came out. i will try hooking up a gerry can today and will let you guys know the results. Do you know if you should be able to blow thru the elec. pump freely? It is very hard to do that? Also what about a vapor lock in the tank could this be a possibility? once again thanks for the help.

 

[Bondo]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

Do you know if you should be able to blow thru the elec. pump freely?

Nope...

Also what about a vapor lock in the tank could this be a possibility?

Nope,... That's Impossible...

 

[Maclin]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

Volvo Penta 4.3's with electric fuel pump have some wiring component considerations involving separate start solenoid and alternator circuits and components (i.e. diodes). Power to the fuel pump during cranking is supplied from the start solenoid, while power for running is supplied from the alternator. I know I have seen Don S provide a diagram and troubleshooting text or two about this, I am not sure if it is up in the stickies or not. I apologize for not being able to get more specific.

In any case:

• There should be no voltage at the fuel pump with the key in just the ON position.
• There should be voltage at the fuel pump during cranking when the key is in the START position. If not then something has failed in the solenoid componentry or wiring thereof. If voltage is present at the pump during cranking then fuel should be getting to the carb via the pump, if not then there could be restrictions along the line somewhere, or the pump is failing.
• There should be voltage at the fuel pump once the engine is running. If not there is a problem with the alternator circuit component/wiring that supplies this "separate" supply.

 

[MIKESANDO]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

I tried the external gas tank but the same results. no fuel to the carb. Would that mean it has to be the fuel pump? i just want to try every thing possible before I buy a fuel pump due to the cost of it ($130-170).

 

[CheapboatKev]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

Have a read at this very similar issue.
Looks like it was due to a defective alternater...

http://forums.iboats.com/showthread.php?t=359363

 

[bruceb58]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

You need to go up to the adults section and download the manual for your engine. Once you have that, you can bypass the fuel pump relay and apply power directly to your pump. If that works, your pump is good and you can concentrate on figuring out why the relay isn't being powered.

Like a previous poster said, the relay coil gets it's power from the starter solenoid during start and the L2 terminal of the alternator while the engine is running. Both of these wires going to the relay go through their own diode.

 

[MIKESANDO]

Re: Volvo Penta 4.3 No Gas Getting to CARB!!!!

okay i will try that and get back with you guys...thanks so much for the advise.