1995 Volvo Penta 4.3GL PHUB no fuel to carb

[skiffguy18]

First off I must say I have read many many posts here over the last 6 months and have never had to post due to the help provided by previous questions. Thanks to all for that. I purchased my boat about 6 months ago and have tackled every issue that came my way but this one is stumping me. I recently rebuilt the raw water pump and the heat exchanger and the boat ran great all day Saturday. I dropped the boat in the water monday started it up and backed off the trailer and it died and wouldn't restart . I have narrowed it down the the fuel system. There is no fuel getting to the carb. I changed all the fuel filters and verified the screen at the carb inlet was not plugged. I removed the pump and bench tested it with 12V and it ran (did not pump fluid just verified it makes noise). Hooked my meter to the fuel pump harness and turned over the motor and got 10V to the harness. Poored fuel into the carb started it up and got 12.5V to the harness with the motor running before it died. That is were I'm at currently and could really use some advice as to were to go next. I was thinking about connecting 12V to the pump and see if it is actually pumping fuel? The way I understand it is the fuel pump runs off normal battery voltage when you are starting it and then switches over to alternator power when the key is released ? Could the diode in between the alternator and the fuel pump relay be bad? If so were is that damn thing? The green wire comes off the alternator, into the harness, and then comes out at the relay. If that diode is bad could that make the pump not work? Wouldn't the 10V on startup be enough to at least make the motor start? Any help would be greatly apreciated. Fishing is just starting to pick up and my boat won't start :facepalm:

 

[Don S]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

Since you know the pump runs, here is one point. DO NOT run it without fuel, that gas is also what lubes the pump. What you need to do is fill the filter with clean fuel prior to installing it on the engine. Then the pump will prime much quicker. Below is a picture of a typical fuel pump wiring diagram like you have. if you remove the relay, and with a meter check between terminal 30 (12V) of the relay socket and 86 (ground), you should show battery voltage, even with the key off.
if you show voltage, use a jumper wire between socket terminals 30 and 87 and the pump should run, and if you have fuel in the filter, it should fill the carb, and you should be able to hear it.

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[skiffguy18]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

I was hoping you would reply. I can't tell you how many issues I have worked out reading your posts. I'll give it a try when I get home tonight and let you know what I find. Thanks !!

 

[skiffguy18]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

Ok, sorry it took me a couple days to get the time to mess with this thing. I removed the fuel filter and it was full. Put it back on and removed the relay. Jumped the pump and it ran. I could hear it fill the bowl on the carb. I installed the relay, put the muffs on the drive and it fired right up. I ran it for about 30 minutes in the driveway. I stopped it and started it several times and it is running perfect. Do you think the pump lost prime some how? I am still a litte worried that I may go out and it won't start again. What do you think. Thanks for the detailed troubleshooting info. I love this site.

 

[Don S]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

It's possible the fuel pump is not running when you crank the engine over.
Was there any corrosion on the relay pins or the socket connections? Removing the relay could have cleaned them a little to allow it to start.
You may also have an open diode in the start circuit. (orange wire and the yellow/red wire).
To test it, first remove the coil wire from the distributor and ground the end. Then remove the relay hook your DVM up to terminals 85 and 86. Now crank the engine like you was trying to start it and see if you have voltage. IF you do, all is well, if not, the diode may be open and not allowing the pump to run, or a broken wire between the start relay and fuel pump relay.

One note, since the start and fuel pump relays are the same, it wouldn't hurt to carry a new spare on the boat. May save yourself a days boating having it handy.

 

[skiffguy18]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

I did the test you suggested and I got voltage when turning the key. The fuel pump is getting voltage on start up. Is it possible the pump sucked air some how and lost prime? A couple of the blades on the relay did have some crap on them and I cleaned them off. I will get a couple back ups to keep on the boat next time I'm at the parts store. Do you think I should test anything else or should I just go out and run it and see what happens?

 

[Don S]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

Do you think I should test anything else or should I just go out and run it and see what happens?

If it's working, what would you check for?

 

[skiffguy18]

Re: 1995 Volvo Penta 4.3GL PHUB no fuel to carb

I think I am going to verify that the fuel tank breather is not plugged and take it out Thursday. I'll let you know how it works out. Thanks for all your help !!

 

[Dougedoug]

I the fuel pump wiring diagram is a diode. Where can you purchase a replacement? I have a 2003 volvo penta 4.3gl?

 

[GA_Boater]

I the fuel pump wiring diagram is a diode. Where can you purchase a replacement? I have a 2003 volvo penta 4.3gl?

Sorry. guy - I don't understand what you are looking for - A diagram or diode.

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