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View Full Version : Vapor Lock Any one had this problem



TCHB
08-11-2003, 07:07 PM
This last weekend out at Havasu my 454 Magnum vapor locked on me. Any one of you had this problem befor???????????????

Ntwotrance
08-11-2003, 07:43 PM
not on a boat...only on an old truck I had...

NOCTURNAL
08-12-2003, 12:57 PM
I had the same problem with my 454 Mag. None of the service centers could solve the problem. We finally put a Whipple Charger on the motor - problem solved.
Aside from that, I was told to depress the Schrader valve (bicycle tire valve) on the fuel rail to release any air bubbles. Once the gas starts to flow out of the valve, stop the process and wipe up any spill. Try the motor and see what happens.
I tried all of the other things...wait for a few minutes, etc, etc...none of them worked. Try the valve and let me know if it helps. Luckily we got rid of the POS Mercruiser fuel injection and the problem.
Does anybody know why Mercruiser put the fuel cooler right next to the engine block? That doesn't seem to be a very cool spot.
In regards to the fuel pump "pushing" the bubble out, I have two batteries sitting in the garage that I burned out cranking the motor over and over again. The vapor lock happened nearly everytime the engine was run hard.
[ August 12, 2003, 02:00 PM: Message edited by: NOCTURNAL ]

TCHB
08-12-2003, 05:57 PM
Yes the gas/water seperator is located right next to the exaust and it has a cool can (plastic) that goes around the can filter. After the vapor lock I removed the gas/water filter and put it back on and the boat started. This is the first time this has happened. A friend of mine Dennis tells me that he heard that certain year 454 Mercury engines only have a electric fuel pump and no mechanical pump. He heard these engines will vapor lock.

TCHB
08-13-2003, 08:05 PM
A friend just sent a Mercury Bullitin that talks about the vapor lock problems. The bullitin explains that the hot engine compartment can cause the vapor lock. The make a kit that will help the situation.

TANGO424
08-13-2003, 08:11 PM
Try a wooden clothes pin on the fuel line that runs from the cooler to the fuel rail
old trick from the days before fuel injection
and carbureted engines ...
but to tell you the truth fuel injected engines dont vapor lock im not sure if yours is or not if it is there might be something else causing the problem

Jrocket
08-13-2003, 08:16 PM
My HP500 does it when its really hot out.After sitting for long periods of time at the sand bar or on shore it will do it.Leave the engine hatch open alittle when parked and it will help.I put a damp towel on the intake if the hatch has to be shut for awhile.

ColeTR1
08-13-2003, 08:30 PM
When it is really hot try to keep lots of fuel in the tanks. EFI recycles the fuel back to the tanks. When the fuel is low that little bit of fuel makes more round trips threw the fuel pump and the hot injector system. Making the fuel in the tank even hotter. My friends 38” Formula had this problem. He said that was a recall from Mercury to fix vapor lock.

Sun burners
08-14-2003, 08:46 AM
Funny I thought it was just my engine!
My 502 mag did that this weekend for the first time. Everything in the engine compartment was HOT! After I let it sit about 10 minutes with the hatch open and me dripping sweat and alot of trying it started up and drove fine the rest of the weekend!

Boozer
08-14-2003, 10:04 AM
The fuel system you guys have probably recirculates the fuel. I had a car that had this problem and all of my friends had the same problem with their cars. The fuel will sit in the fuel rail and get WAY to hot and the motor just wont fire up. Best thing to do was to open the hood and let some of the heat vent out but sometimes I would get stuck at the gas station for 15-20 minutes on a hot day. I tried sticking ice on the fuel rail but it never seemed to help out any.
[ August 14, 2003, 11:04 AM: Message edited by: Boozer ]

Daytona19
08-14-2003, 03:21 PM
Had it happen on my Merc OB last weekend. I filled the tanks and let it sit two days before we went boating. At the ramp it wouldnt start it vapor locked!! Basically the gas expanded from sitting in a hot garage and blocked the vented caps I have and wouldnt let fuel thru. Had to siphon gas into the line and turn on the elec fuel pump then it flowed and she was rockin did 104.7 that day on GPS!!!

dkreuzen
08-14-2003, 04:23 PM
For those of you that think EFI does not Vapor Lock in a boat, check out this Mercrusier Service Bulletin.
http://www.bravodrives.com/GasolineService/Bullet/99/99_07.pdf
Also Boat EFI does not recalculate gas back to the tank like a car. My HP500EFI recalculates the gas back to the fuel filter/separator.

TCHB
08-14-2003, 06:49 PM
Dennis I did check the bullitin out and yes my fuel injected Mercury did vapor lock. I will try and add more vents into the engine compartment. Thanks for the information

TCHB
08-16-2003, 05:53 PM
I got an email from another vapor locked boat. He said he was idling in the channel with warm water and no air flow to the engine compartment and the boat vapor locked when he shut it down and tried to restart it. If you pull the water seperator off will this break the vapor lock?

AzDon
08-16-2003, 08:09 PM
Several ideas: mount a fluid to fluid heat exchanger near the fuel connection near the injection and run your fuel and cold water thru it. Another variation of this would be to bend up a metal cold water line to run next to the fuel line. Wrap them together with heating and a/c metal tape (industrial duct tape) and them wrap with foam pipe insulation from the hardware store

TCHB
08-18-2003, 07:36 PM
It seem like the vapor lock problem is more normal than I thought. I am going to try and vent the engine compartment better. My engine compartment is sealed pretty tight.

BajaMike
08-18-2003, 08:21 PM
TCHB:
It seem like the vapor lock problem is more normal than I thought. I am going to try and vent the engine compartment better. My engine compartment is sealed pretty tight. I wonder if running the engine compartment blower at shutdown and longer before startup will help?
Mike
idea