Fuel pump not running unless jumpered

First, I have a 1995 Chapparal with a Volvo Penta 4.3 GS serial #4110121763...43GS PHUB. I'll try to keep this short but I don't want to leave out any details that may help.

I was out on the lake last summer...the water pump impeller took a dump and the engine started to overheat so i cruised back to the dock and shut her down within 5 min of realizing the overheat situation. The boat has been sitting in my garage ever since. I replaced the impeller last week. I had to take all the water hoses off as well as the thermostat and remove the pieces of impeller. In the process I pulled the main engine harness cable from it's plug to get it out of the way. Other than that, I didn't screw with any wiring. Once I put all the hoses back I plugged the engine harness back in.

I then tried to crank it up to test the water pump out (I had my water hose hooked up to the outdrive while sitting in the driveway). It wouldn't start. It has started for the last four summers even after sitting all winter with no winterization. In any case, I sprayed a bunch of ether in it and it never got going on its own.

I pulled a spark plug and tested it. It has spark. All the other electrical stuff works (stereo, blower, horn, etc.).

The fuel pump doesn't run when you turn the key to run. I do have 12 volts on Pin 30 of the fuel pump relay connection all of the time even when the key is off. I don't get any voltage on Pin 86 when turning the to run or when cranking.

Also, I found this thread and followed your directions:

http://forums.iboats.com/showthread.php?t=290966&highlight=fuel+pump+power

I put a jumper between 30 and 87 which did make the fuel pump run. I also disconnected the metal fuel line between the pump output and the carb, then I connected the jumper to see if fuel was actually being pumped to the carb...there was a short spurt and a gurgle and then nothing after that even though the pump was running.

I pulled the fuel filter off and poured it out (it was about 1/3 full) then filled it up to the top with gas and reinstalled it.

Then we jumped the fuel pump again and gas came out of the carb supply line in a hurry...so we hooked it back up to the carb. Then we had everything hooked back up and so we jumped the fuel pump, started cranking the engine, and it fired up! We had to keep the throttle at high idle to keep it from running rough. We left it running for about 10 minutes.

During that time I checked the voltage between 87 & 85...I never got anything.

I checked the voltage at the green wire on the alternator and it was 13.8 V.

Then I turned it off and here we are. Oh yeah, I just installed a brand new relay today.

Any idea what is going on? Thanks for all your help in advance! I really appreciate it.

Re: Fuel pump not running unless jumpered

You have 2 different problems going on to cause both of those problems.
So lets do one at a time.

I put a jumper between 30 and 87 which did make the fuel pump run. I also disconnected the metal fuel line between the pump output and the carb, then I connected the jumper to see if fuel was actually being pumped to the carb...there was a short spurt and a gurgle and then nothing after that even though the pump was running.

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Let's start with the fuel pump and it's fuel. Hook up a remote tank (aka outboard fuel tank) directly to the connection on the engines fuel filter housing and completely bypass the boats fuel system.
Jumper the relay so the pump runs and see if the engine will start and idle. If not, and hopefully your outboard fuel tank has a squeeze bulb, pump it up while it's running and see if that works to make it idle. The pump may be damaged from running dry. Need to find the fuel delivery problem

Re: Fuel pump not running unless jumpered

During that time I checked the voltage between 87 & 85...I never got anything.

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Those would both be hot, so you wouldn't read anything.
When it's running, check between terminal 85 and ground, then you should see battery voltage

I checked the voltage at the green wire on the alternator and it was 13.8 V.

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If you have 13.8 at the alternators green wire, then check at terminal 85 of the relay socket, it should see voltage, but not 13.8.
If you don't, then the diode is burned out and needs replaced.

Re: Fuel pump not running unless jumpered

With the engine not running and the key in the Run position I am getting a constant 2.5 V.

Re: Fuel pump not running unless jumpered

Ok, with the engine running the voltage is 13 V. Also, I am still using the boats fuel system. The engine will definitely not keep running without me throttling up to high idle.

Does this mean the diode is good? What are the options for why it won't run with the relay in place?

Re: Fuel pump not running unless jumpered

mauer03 said:

With the engine not running and the key in the Run position I am getting a constant 2.5 V.

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What has 2.5V
Where did you measure it,
How do you have your volt meter hooked up.

Re: Fuel pump not running unless jumpered

Terminal 85 had 2.5 V when engine wasn't running and 13 V when engine was running.

OK, you are going to love this. I just put the relay back in just for the hell of it and the engine cranked over and fired right up. I started it in high idle...then I backed off on the throttle and it started chugging pretty bad but it didn't stop completely. I then switched it off and then cranked it back up and I got the same results.

One more detail, I installed a new fuel filter this morning.

Re: Fuel pump not running unless jumpered

One more detail, I installed a new fuel filter this morning.

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Did you dump the old one out to see what was inside? That's the only way you can find problems is by looking at things.

Re: Fuel pump not running unless jumpered

I didn't see any solids come out but I didn't dump it into a bowl and inspect the contents so I definitely could have missed something.

So I have a few more questions: since the gas in the tank is from last summer and I never put any Stabil in it...should I try to drain the tank somehow and fill up with new gas? It is also relatively likely that I put 87 Octane in it and not 89 like it says. Should I go buy some octane booster and put it in there? Should I just add Stabil?

The Clymer manual says that the fuel pump is supposed to run for 2 secs when you switch the key to the run position...it isn't doing that. Should I be worried about that?

Re: Fuel pump not running unless jumpered

Your gas is not cause the pump not to run, no reason to dump the gas.

The Clymer manual says that the fuel pump is supposed to run for 2 secs when you switch the key to the run position...it isn't doing that.

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Get an OEM manual set for your engine and drive.
NO, it should not run for 2 seconds, that is for a fuel injected engine only. You have a carbed engine.