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Bad Fuel? Not sure...

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Hi guys - so it was a "fun" weekend.  For starters I have a 2005 Malibu Response LX with an Indmar LCR 320 Engine.  Got to the lake on Friday afternoon.  I took the boat for a rip and it ran great.  Went to ski about 9pm and it barely turned over and then died.  It wouldn't start up.  The fuel pump sounded terrible.  On Saturday morning I jumped on here and saw some topics about cleaning the screen with carb cleaner.  Did that and she fired right up but the fuel pump didn't sound so good.  The pump was whining quite a bit but it ran ok.  I decided to go pick up a new fuel pump on Saturday per the advice of a Mechanic I spoke to.  When I returned to the lake I went to move the boat from the dock to the lift and it wouldn't start.  I put the new fuel pump in and it fired right up.  This new pump sounds just a little different (a little louder as I can hear it while running the boat) but it didn't sound like it was starving for gas and the boat ran fine.

Come Monday.  Ran the boat in the morning for some skiers.  Worked great.  Came back after an hour in the sun to move her on the lift and the pump started whining and again and the boat wouldn't fire up.  I walked the boat on the lift and raised the clam shell.  "Maybe it's hot, maybe it's vapor lock..."  The pump sounded like it was starving for gas.  Decided to change the fuel filter even though I changed it a month ago.  Put the new filter in, dumped in a bunch of seam foam, and some fresh gas.  After priming the pump a few times it sounded better and started right up.  Took the fam skiing for an hour last night with no issues.  This new fuel pump is slightly louder but the boat ran great...  Won't be back until this weekend.

So.....  could it be bad fuel?  Some have mentioned Vapor Lock??  I just bought gas from another station this past round as it was 30 cents cheaper.  There are a few others on the lake that have noticed some issues too.  Some have bought gas from the same location but a few others have bought from other locations.  I'm thinking of ordering a testing kit.

I also checked the fuel pressure.  When priming the pump it was about 60 psi.  If I recall I think when it was running it was 45 to 50 psi.  

Any help would be appreciated.  I'm waiting on a return call from the mechanic too.  Just frustrating as I take really good care of my boat and I'm not sure what the issue is exactly.  

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I went through 2 summers with this issue and finally fixed it permanently by adding the secondary pump.  See post below (towards end, 2nd to last paragraph.)


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FWIW, I have a bit of experience with fuel pump issues and with vapor lock.  2006 21 LSV with LCR engine.

I'd actually never before had an issue, back when I still had ready access to ethanol-free fuel.  But, those days are long gone.

I had my fuel pump first replaced back in 2011.  It was just before a Labor Day weekend, and my daughter and her roommates were planning to come to the lake for the big weekend.  Mechanic at the lake (reputable non-Malibu dealer) said the fuel pump was bad.  He ordered a new one, installed it, checked it, and called me to inform me that the new pump was defective!  He also told me that his supplier didn't have any more in stock.  I called up my Malibu dealer in Austin/Round Rock, was assured they had a fuel pump in stock, drove there and back, and hand-delivered another new pump to the mechanic.  This time, he bench tested it first.  Also defective!  The Malibu dealer did not have any others in stock, but I contacted the Supra dealer in south Austin (they used the exact same pump at the time), was assured that they had a new pump on the shelf, drove there and back, and  handed the lake mechanic another new pump.  Weekend was salvaged!

The mechanic's explanation for why two out of three brand new pumps were bad was:  these [Pierburg] fuel pumps typically sit around in warehouses, lying on their sides, and, with repeated hot and cold weather cycles, there are times when water condensation occurs, even while in enclosed packaging.  If there is even the slightest bit of corrosion between the rotating armature as it sits inside the magnet assembly, built up over time, when power is applied to the pump, that initial resistance to turning can cause the circuitry to overheat and fail (?).

The following September, I again had problems with the fuel pump.  I took the boat into the Malibu dealership.  They diagnosed a bad pump, and I again had a replacement installed.

Fast forward to 2017, and I began to fairly regularly have issues starting the boat, typically only after an uneventful early morning run and then a pause, while we shut the boat down (rested up, listened to tunes, etc.)  The first time it happened, my ski buddy (an amateur mechanic, himself) and the guy who helped tow us in, both insisted that fuel-injected engines don't vapor lock. But, after a little research once I got home, I realized that vapor lock was the likely culprit.  We became more compulsive after that about keeping the blower on, and even venting the engine compartment during shutdowns, but had to resort to pouring cold water over the pump on several occasions in order to get re-started.

I bit the bullet and purchased a secondary fuel pump, Bake's "Fuel Pump Vapor Lock Prevention Kit."  Fairly easy DIY install.  I've not had a problem since. YMMV.

Edited by srab
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Wow!  That's a lot of fuel pump issues.  I just read up on that kit and it sounds like it only works on 2006 and newer boats but it also states to rule out many of the other issues soon.  Our neighbors had similar issues for some time and keeping the blower on seemed to help.  I wonder if I'm dealing with some Vapor Lock too.  I spoke to one of our local dealers and they said it sounds like bad gas.  I'm thinking of draining the tank and getting ethanol free as we have a station that is about 15 minutes away.  I now even wonder if my old pump was bad in the first place......

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6 hours ago, kylegansel said:

So you just did it cause you felt like you weren't getting the pressure you needed?

No, same reason as @srab above, vapor lock.  The secondary pump provides around 6psi and this keeps the main pump pressurized and this keeps the fuel in the pump from vaporizing, which then makes the pump cavitate, leading to inadequate pressure for running the engine.  This is only necessary for main pumps that are mounted to the engine block, not the more modern pumps located in the fuel tank where they stay plenty cool.

Edited by formulaben
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I e-mailed Malibu but what should my pressure be after the pump is primed (before engine start) and what should operating pressure be when the boat is running?

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http://media.channelblade.com/EProWebsiteMedia/3506/Indmar Owner's Manual 2003-present.pdf

it's in your owners manual....60 psi.

should not get below 55 when running, I've been told.  Our area has seen rash of fuel pressure regulator failures.  Not sure why.  Old pump could have been on the way out, new pump provided more, but regulator still not behaving as it should.  just a thought.

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1 hour ago, kylegansel said:

 it only works on 2006 and newer boats

Hopefully yours is just a fuel issue.  If yours acts up again an hour or so after shutdown, though, try pouring cold water directly onto the pump and filter.

But, the vapor lock issue, and the secondary fuel pump solution, was a problem going back to at least 2003 (The 2003-2006 boats all use the same fuel pump).  With this setup (also on Moomba/Supra boats), the fuel line, from the tank, through the in-line fuel filter, and on up to the fuel pump, is not pressurized. 

The secondary fuel pump goes between the tank and the in-line filter to [slightly] pressurize the fuel coming into the fuel pump, preventing vaporization during heat soak.

Malibu switched to an in-tank fuel pump in 2007, obviating the need for this fix.


Edited by srab
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Thank you for all the info.  I'll test the pressure again this weekend.  I spoke to one of my close friends who sells automotive parts.  He thinks it's possibly bad gas also.  He gave me some ideas.  Appreciate all the help!

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