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fuel line/pump problems


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hello mbc,

i am hoping someone can help.

it seems my boat (2000 sportster) is starving for fuel. we were out on the course and the motor died like it had run out of gas. we had to be towed back which is very embarassing. i filled the tank and it only took 10 gallons. it never that simple. i then removed the fuel line before the carb and could not get any fuel to come out of the line. proceeded to shoot some carb cleaner and the motor would turn over and run fine. removed the fuel line before the pump and could not feel any suction. removed the fuel water separator before the fuel pump and it was full. the gas looked clean. i then reasoned that the fuel pump was bad and ordered a new one. replaced it. had trouble getting it to draw so i replaced the fuel/water separator and filled it with fuel. filled the fuel lines and pump as best i could. started the motor with starting fluid through the carb and then it ran on it's own for 3 or 4 minutes. shut it off. went in to have dinner. after dinner we went for a test ride. the boat started right up. idled out to the bay. as i increased the gas, it skipped only once. I did notice that the tack was acting erratic. cruised around for ten plus minutes at varying speeds. no problems. all seems to have worked itself out. brought it down to idle to go for a swim and noticed it skipped again. got worried. brought it back up to speed and headed for the dock. it ran fine until i had to idle through a no wake zone. here she quit. could not get her to refire. (i did not try the starting fluid because i left it on the dock.) again towed back to the dock and put her away on the lift. does anyone have any ideas? air leak? where? the line form the tank to the fuel water filter seems to be always full. what should i be looking for?

thanks,

oldbarn

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Is it a mechanical fuel pump on the side of the engine block?

If it is, did it have the vent line hook up? Did you make sure the rod that operates from the cam is in the correct position. There is a bolt on the block in front that you can remove and when you use a bolt in it's place that has a longer thread length, you can hand tighten it to hold the rod in place (up) while installing of the pump. After the install, put the original one back in with a little silicone around the head so you don't have a leak.

Do you have EFI? Whole nother can of worms!

Also, borrow a fuel pressure gauge and check you fuel pressure.

Some boats have a second filter by the fuel tank (I don't on my '95), check or replace it as well. You may have fuel but not enough to keep it supplied.

Just some thoughts.

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Check your vent hose and make sure it isn't crushed or kinked or got stopped up at the vent opening somehow. If it is stopped up it will draw a vacuum on the tank and won't be able to deliver fuel

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I'm thinking with you sunsetter on the boat may have 2 FUEL FILTERS. I heard that one may be in or right next to the tank. A fast way to see if your vent tube is blocked is when it die's take off you fuel cap and lisen for a sucktion noise.

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If the boat is out of the water, he can take the filler cap and the vent cap off. Then blow some air threw the vent. He should be able to hear it come out the filler opening. Or it can be done the other way, it doesn't matter.

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Is it a mechanical fuel pump on the side of the engine block?

If it is, did it have the vent line hook up? Did you make sure the rod that operates from the cam is in the correct position. There is a bolt on the block in front that you can remove and when you use a bolt in it's place that has a longer thread length, you can hand tighten it to hold the rod in place (up) while installing of the pump. After the install, put the original one back in with a little silicone around the head so you don't have a leak.

Do you have EFI? Whole nother can of worms!

Also, borrow a fuel pressure gauge and check you fuel pressure.

Some boats have a second filter by the fuel tank (I don't on my '95), check or replace it as well. You may have fuel but not enough to keep it supplied.

Just some thoughts.

The fuel pump is electric. I did not see a vent line. The motor is carburetored. I am not sure if there is a fuel filter near the tank. I will look into that. I sure hope not. I have been told the seat is difficult to remove.

Thanks for the tips.

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If the boat is out of the water, he can take the filler cap and the vent cap off. Then blow some air threw the vent. He should be able to hear it come out the filler opening. Or it can be done the other way, it doesn't matter.

Thanks, I will try these ideas tonight and let you know how I make out. I appreciate the help. Summer is too short around here to be messing with issues like this.

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I know on my Sunsetter that if you take the carpeted fiberglass cover that covers the gas tank off (it slips right out of the storage area), there's an in-line filter back there just off the gas tank.

However, given your symptoms, it sounds like it's unlikely that's the culprit. I would expect if that little guy was clogged, it would run ok at idle and loose power when you throttle up. It's a cheap part to replace though and is worth a shot.

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anti backflow check valve lactation would be at the top of the fuel tank and only look like a adapter. pipe to barb.

I had one clog on me in my fourwinns. fibers from building the tank were stuck at the check ball so bad no fuel could pass.

The clue's for me are. CARB, and

" i then reasoned that the fuel pump was bad and ordered a new one. replaced it. had trouble getting it to draw "

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hello mbc,

i am hoping someone can help.

it seems my boat (2000 sportster) is starving for fuel.  we were out on the course and the motor died like it had run out of gas.  we had to be towed back which is very embarassing.  i filled the tank and it only took 10 gallons.  it never that simple.  i then removed the fuel line before the carb and could not get any fuel to come out of the line.  proceeded to shoot some carb cleaner and the motor would turn over and run fine.  removed the fuel line before the pump and could not feel any suction.  removed the fuel water separator before the fuel pump and it was full.  the gas looked clean.  i then reasoned that the fuel pump was bad and ordered a new one.  replaced it.  had trouble getting it to draw so i replaced the fuel/water separator and filled it with fuel.  filled the fuel lines and pump as best i could.  started the motor with starting fluid through the carb and then it ran on it's own for 3 or 4 minutes.  shut it off.  went in to have dinner.  after dinner we went for a test ride.  the boat started right up.  idled out to the bay.  as i increased the gas, it skipped only once.  I did notice that the tack was acting erratic.  cruised around for ten plus minutes at varying speeds.  no problems.  all seems to have worked itself out.  brought it down to idle to go for a swim and noticed it skipped again.  got worried. brought it back up to speed and headed for the dock.  it ran fine until i had to idle through a no wake zone. here she quit.  could not get her to refire.  (i did not try the starting fluid because i left it on the dock.)  again towed back to the dock and put her away on the lift.    does anyone have any ideas?  air leak?  where?  the line form the tank to the fuel water filter seems to be always full.  what should i be looking for?

thanks,

oldbarn

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I did not see a vent line. The motor is carburetored. I am not sure if there is a fuel filter near the tank. I will look into that. I sure hope not. I have been told the seat is difficult to remove.

Thanks for the tips.

Do you have an overflow vent on the side or back of the boat where fuel flows out if you overfill? That would be the vent. You need to get to the tank and remove the line from that end and check end to end. You may also need to remove the fuel pickup from the tank and make sure it isn't stopped up. I think there is a good chance there is a filter near the tank, not sure though.

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Ok, so it has an electric fuel pump that has been replaced along with a new fuel filter (the big one) and a carburetor.

Yes, check for the other fuel filter near the tank. Put some gas additive in the tank to help clean the system out (can't hurt). Check the tank vent. If anything is gunked up in the carb, try some carb cleaner in the bowl vents. The additive will do the rest if there is some minor build up. Check the install flow direction of the new fuel pump (sorry, it had to be said). Check all sines for any kinks from working on it.

I'm thinking that it is a supply to the pump issue. You can pull a line off after the fuel separator filter and pump gas into a gas can and see if it dies out or slows down if you can't get a pressure gauge to test the new pump.

Question: When the engine dies out, can you still hear the fuel pump pumping? Just a thought. If not, there is a blockage some where after the pump.

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Sunsetter are you saying to take off a fuel line befor and after the fuel pump? Then have a full can on the sucktion side and a empty one on the outlet side, putting a hose in each and then turn on the pump to see how much fuel the pump can flow? Then put the sucktion line back on the tank line to see if there is a clog (by comparing how much is flowing out each way) of the supply line?

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the power supply to the electric fuel pump runs through a normally open oil pressure switch . the switch is located at the rear of the block , next to the distributor. with the key on jump the 2 terminals of the switch & the pump should run. my sportster is an 01 & does not have a filter at the tank. only 1 spin on filter near the pump.

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OK,

I have had a couple of days to fool with this.

Background. The boat is a sporty. 2001. Indmar 350 with carb. The fuel pump, which I just replaced is electric. I have also replaced the fuel water seperater. Added fuel line cleaner into the tank. Shot the carb with carb cleaner several times. Checked all the fitting with soapy water for leaks. I have checked the rear vent. It appears to be free and clear.

Here are the current symtoms.

The boat now starts regularly. It will run at idle fine. It will run fine with the transmission disengaged and the motor reved up.

I can idle out to the lake (3/10 of a mile) and then drive off. (The motor is warmed. Water temp is 160 while under way. ) I can pull tubes/waterskis stopping the boat and shutting it down while we change over all day long. It always seems to start.

My problem is coming down to idle speed and making headway. Once the boat is up on plane, if I bring it down to headway speed, it will stall after 100 yards or so. Sometimes it stars back up with the key. Sometimes I need to add starting fluid to the carb. I have also been able to stop it for dying by reving it up, but it wants to die out as soon as we return to headway speed.

Any new ideas?

Thanks.

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I'd look closer at the carb. Take out all jets and clean really well. Make sure the float is moving freely. Possibly larger idle jet.

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I'd look closer at the carb.  Take out all jets and clean really well.  Make sure the float is moving freely.  Possibly larger idle jet.

I will look into the carb and jets tonight. Thanks for the tip. I suspected that that might be the next route. I was hesitating because it was running fine at idle.

Thanks

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my 1992 flightcraft has a filter at the carb. Have you checked this?

OldHickory

No, I haven't looked into that yet. Someone had mentioned that to me last night. I will investigate that as well.

It seems that the consensus is that it is now a carb issue?

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I just did a fuel filter in a 2005 sportster... it was locatd under the hatch behind the engine box. If you pull that board out, you will see it there. Yours may be behind the rear seat though. It doesnt hurt to change it... $11 and good peace of mind.

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For those of you following this thread and offered advice. Thank you. It turns out that a faulty oil sensor is the key to my troubles. It turns the fuel pump on and off. In my case, when the oil pressure drop below 40 psi., then the sensor shut the fuel pump off occasionally and the carb went thirsty. I should be back in business soon. Thanks again,

Oldbarn

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  • 13 years later...
On 7/28/2005 at 7:31 PM, oldbarn said:

For those of you following this thread and offered advice. Thank you. It turns out that a faulty oil sensor is the key to my troubles. It turns the fuel pump on and off. In my case, when the oil pressure drop below 40 psi., then the sensor shut the fuel pump off occasionally and the carb went thirsty. I should be back in business soon. Thanks again,

Oldbarn

What sensor are you referring to?

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