Engine hard starting after setting few hours

Discussion in 'Announcements & FAQs' started by Greg Matt, May 29, 2018.

  1. Greg Matt

    Greg Matt New Member

    2
    May 29, 2018
    Indiana
    380 Sundancer 2000
    Horizon 8.1
    I have a 380 Sundancer 2000. Starts a marina no problem. Run for 30 minutes to 1.5 hours. After stopping for 2-6 hours the starboard engine starts for a few seconds and then quits. After 10-15 minutes and many restarts it finally stays running. Next morning it starts just fine again. Any ideas on what’s the solution.?
     
  2. paulswagelock

    paulswagelock Well-Known Member

    Oct 25, 2010
    pa
    2018 SDX 270 OB 300 Verado
    Verado 300
    Sounds like vapor lock. Experiment with opening the hatch after a run and leaving the blower on to see if that eliminates it. If so, then you know the problem to chase.
     
  3. thosmann1

    thosmann1 Member

    91
    Jan 19, 2009
    Key west Florida
    500 Searay Sundancer
    Cummins QSM11's
    Been there, fixed that!
    What you have is vapor lock, it happens after a hot engine sits in a hot engine compartment causing a “heat soak” where the engine actually gets hotter instead of cooling down. I tried opening the hatch, no good, it still would not start. Hitting the key on and off didn’t work because the fuel pump could not “push” the air through the lines.

    The excessive heat causes vapor lock because the fuel sitting in the fuel line vaporizes which causes a “air gap” in the line that the fuel pump cannot “pull” through to the fuel rail. Most mercruiser EFI engines need either 39 psi or 43 psi, any less and it ain’t startin’!

    The permanent and CORRECT fix is this, and it will never happen again. Mercruiser makes a low psi “push” pump. The kit comes with: pump, wire harness, fittings. Simple to install, just install it inline between the fuel tank and water separator filter. The wire harness is plug and play and the pump only comes on when your other fuel pump is on. These “kits” are found online or through your Mercruiser Dealer and any brass fittings you may need are available at HD.

    The other fix is this: Go online and find aftermarket 5 psi fuel pumps, make your own harness. Then pray you don’t blow yourself up because either you or the backyard mechanic who installed it didn’t do it correctly!

    The reason fuel vaporizes faster at different times of the year because the fuel companies add ingredients to increase “Rapid Vapor Preasure “ (RVP) in the colder months.

    You will spend a lot more to do it correctly, but if safety is important to you do it right the first time!

    I hope this cleared it up, it took me months to figure it out and all Mercruiser techs I spoke to could not figure it out or have a cure.
    Good luck with this,
    Bow Tie
     
    susanandlance and Brock Chobar like this.
  4. Greg Matt

    Greg Matt New Member

    2
    May 29, 2018
    Indiana
    380 Sundancer 2000
    Horizon 8.1
    Thanks for the input, I’m going to try that.
     
  5. PlayDate

    PlayDate Well-Known Member

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers

    Do you have a Mercruiser part number for this? I'm not sure I understand how putting a 5 psi pump in line with the 40+psi EFI pump works.
     
  6. thosmann1

    thosmann1 Member

    91
    Jan 19, 2009
    Key west Florida
    500 Searay Sundancer
    Cummins QSM11's
    Sure, no problem.
    Your inline fuel pump in the cooler feeds the fuel to the rail. When you have vapor lock (air space between the fuel line and fuel filter) your fuel pump cannot create the 39 psi (or 43psi depending on the engine) it needs to run the engine and the engine stops. Basically, it runs out of gas.

    The low psi “push” pump pushes the fuel back to the fuel water separator filter and fills the filter full of fuel taking up the air space and allowing the fuel pump to supply fuel to the fuel rail.
    This is what happens when fuel vaporizes quickly because of elevated additives in the fuel increases the RVP (rapid vapor Pressure).

    I don’t have the push pump part numbers, but I’ll research it and post on this site. It’s an OEM kit complete with everything you need including a plug and play wire harness that allows the additional pump to only come on when your engine is running. A good parts guy can research it or call Mercruiser Marine, maybe you’ll get someone who is knowledgeable.

    Bow Tie.
     
  7. thosmann1

    thosmann1 Member

    91
    Jan 19, 2009
    Key west Florida
    500 Searay Sundancer
    Cummins QSM11's
  8. thosmann1

    thosmann1 Member

    91
    Jan 19, 2009
    Key west Florida
    500 Searay Sundancer
    Cummins QSM11's
    Everything in this kit you’ll use except for the large fuel filter and fuel line, the 502 uses the filter and line. Otherwise, you should be good to go. The pump gets installed between the tank line and fuel water separator. I installed them on the inside of the stringers by cutting the fuel line. I had to change the fittings to barbed fittings to accommodate the fuel line, double clamped and installed on the inside and high on the stringer so nobody can accidentally hit it or kick it. Something to remember is: if you are using the barb fittings that come with the kit, ok. IF, you have to buy different brass barb fittings use a thread sealer good for fuels. AND, be sure to inspect for any leaks before, during and after the engine is running. If you have a fuel shutoff at the tank you’ll need to shut off the fuel. If you do not have a fuel shut off you’ll need to either pinch the hose or move the cut end above the tank so it doesn’t drain. You can put a container under the hose on the filter side. Only a small amount will come out of the filter side. After you get the pump installed you’ll need to Prime the line by switching the pump on/off 3-6 times. It won’t hurt anything if you toggle it too much, it’ll still start.

    PS. NO SMOKING!


    Bow tie
     
    Last edited: Jul 2, 2018
    jzanthony likes this.
  9. face89

    face89 New Member

    5
    Aug 4, 2009
    Chicago, IL
    380 Sundancer 2000
    454 Mercruiser Mag MPI Horizon Gen VI Inboards
    Just saw this....I must have the same problem...have had this happening for years! However only on the Starboard engine. The way I've lived with the issue has been to raise the throttle handle to 50%. (I recall reading somewhere - that is how you fool the computer - something to do with a flooding condition.) Anyway, it usually fires right up, but I have to be ready to quickly back off the throttle.

    Its annoying and somewhat disconcerting though to have to start the boat this way at the end of each day. So I'm definitely gonna try ordering the anti vapor lock kit.

    My only question is.....does anyone have a guess as to why this only happens with my starboard engine? Normally i'd apply fixes or maintenance to both engines equally, but I've literally never had this issue on the Port side...and its not exactly a cheap fix.


    (And why didn't Sea Ray recall these pump assemblies long ago!? no need to answer that...lol)

    Thanks!
    Paul
     
  10. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    The CF2 pump is on the port side of the motor, which would place the starboard pump directly between the 2 engines.
    A cheaper fix would be to plumb the return line from the pump back to the fuel tank. The way it's setup now it gets returned to the filter, so it doesn't get a chance to cool.

    So if it starts easily by advancing the throttle what's the big deal ?
     
    Sublimetime likes this.
  11. Sublimetime

    Sublimetime Active Member

    686
    Oct 22, 2007
    clifton nj
    420 da
    454
    I think scoflaw is onto something here. When running the fuel pump keeps recirculating the unused "portion" of fuel from the pump to fuel rail back thru the return line into the filter housing. Not only the heat it picks up from the engine room but liquids heat up from the pumping action. When you shutdown you have a hot fuel condition right where you need it the least. Return line to tank would be ideal.

    FACE 89---Is it your starboard engine pump that is located near boat centerline, absorbing heat from both motors?

    In the mean time just keep advancing the sticks, but be quick to pull them back.
     
  12. face89

    face89 New Member

    5
    Aug 4, 2009
    Chicago, IL
    380 Sundancer 2000
    454 Mercruiser Mag MPI Horizon Gen VI Inboards
    Thanks for the responses guys. I spent the last couple days with my mechanic changing a genset thermostat and also troubleshooting an electrical issue where I wasn't getting power to the starboard start/stop switch on the dash....turned out to be a blown 90amp fuse in front of the starter motor. $25 fix.

    As for my potential vapor lock issue, I'll have to consult with the mechanic. It makes sense that a pump between the two engines would be hotter.

    I've only had my boat in the water for a week now (replaced all the manifolds, risers, and elbows this year, along with oil and coolant hoses, and more). It seems like my fuel/starting issue is getting worse. I had trouble yesterday with a cold starboard engine. Had to raise throttle to 50% to start. Not sure if our 95+ temps in Chicago this week could have anything to do with it.

    But I do want to get this fixed. Im concerned whatever is causing this may get worse and someday I may not even be able to trick start the engine. Plus if I'm ever away from the helm, there may be times other people may be starting the engine and revving up the way it does, it cant be healthy on a regular basis.
     
  13. face89

    face89 New Member

    5
    Aug 4, 2009
    Chicago, IL
    380 Sundancer 2000
    454 Mercruiser Mag MPI Horizon Gen VI Inboards
    Spoke to my mechanic....because this is now a problem even in a cold start condition, he thinks I have a bad fuel pressure regulator. The diaphragm inside the regulator may be leaking, which results in unregulated fuel pressures and fuel leaking directly into the intake manifold from the vacuum line, which causes an overly rich mixture and in turn, requires adding more air (opening the throttle wider) to start the combustion process. Thoughts?
     
    joeyleggz likes this.
  14. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Just because that system is 20 years old , I would replace the whole thing from A to Z. Pumps ,regulators, hoses , the whole deal. Just did that myself and holy shit it's like a whole new ride and may last another 20 years. Sometimes just picking away at it can be frustrating and has its share of down time and pricey, especially if your paying for labor.
     
    susanandlance likes this.
  15. Bayou340

    Bayou340 Member

    37
    Feb 26, 2018
    340 Sundancer, 2000
    Mercruiser 7.4 MPI
    I have been experiencing the exact same situation recently. I have tried everything. Idling engines, blowers running, open hatch, nothing works. Has driven me absolutely crazy. If I have to leave the hatch open after using the engines, I can’t really use the boat.

    Google Mercruiser bulletin 99_07. Describes the problem to a T. It also lists fixes and the part numbers for the check valve and fuel pump kit.

    Would wrapping the lines in heat shielding prevent this? It would be a lot less expensive than two of these pumps.
     
  16. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    I've got my lines wrapped, and don't have a problem. The Airtex E11004 is the perfect fuel pump replacement for the CF2 and at $70 it's a deal
     
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  17. face89

    face89 New Member

    5
    Aug 4, 2009
    Chicago, IL
    380 Sundancer 2000
    454 Mercruiser Mag MPI Horizon Gen VI Inboards
    Do you guys still think its a temperature or vapor related fuel system issue given its happening even when I haven't started my starboard engine in a few days?
     
  18. 370Dancer

    370Dancer Active Member

    967
    Oct 2, 2006
    Florida - Alabama
    1998 370 Sundancer
    380hp MAG MPI Gen VI with V drives
    Not me. pull the vacuum hose on the regulator and see if any gas comes out. You'll have to unroute the line so gravity will be on your side. If so, the diaphragm has probably seen some non-ethanol gas, or just wore out.
     
  19. face89

    face89 New Member

    5
    Aug 4, 2009
    Chicago, IL
    380 Sundancer 2000
    454 Mercruiser Mag MPI Horizon Gen VI Inboards
    Thank you. What does CF2 refer to btw?
     
  20. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Cool Fuel 2 . Probably what you have if your fuel pump is on the port side of your engine
     

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