Vapor lock fixed for good boys and girls
05-05-2014, 03:09 PM
#1
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Vapor lock fixed for good boys and girls
For those of you with 454 & 502 mag MPI's whom followed the Vapor Lock issues on my post
http://www.offshoreonly.com/forums/g...ck-issues.html
YES I did the return line to the tank thing, and the checked the valve / spring on the VST. I moved my water fuel separators, bigger new AN fittings and braided lines. All helped but still would Vapor-Lock from time to time..
I finally finished with gutting the entire VST and Mech. pump mess. What a dumb idea that was.. I added 2 Aeromotive marine pumps, 2- 5 micron leaving fuel filters and 2- fuel regulators with by-pass and pressure gauge.. Wiring was easy. Making the braided lines was the hardest part..
I added rubber feet to the pumps which made them 2/3rds quieter. My motors like to be set at 38PSI.
The fuel rails were sent to Eddie Young where he makes it so you feed fuel at both ends of the rail and he mills and adds fittings so you can add your own AN fittings not that special stuff Merc. uses only. He also opens up one injector passage so not as restrictive. I sent Fuel injectors out to be tested and cleaned since already out and older and never been touched since 97.
[ATTACH=CONFIG]523020[/ATTACH]
I figured might as well test it if I'm going to test it.. So I ran her for an hour and didn't let it cool down and shut her off with no bilge blowers and motors hatch down. Had a brew with some tunes and waited about an hour so she would heat-sink to the max in the sun.. They fired right up with no hesitation. In fact it runs better than ever and my mid-throttle punch is way better now too. I tried the same thing with idling for 40 min. Every time all weekend long fired right up.. The pumps are actually cool to the touch, they don't get warm at all. Tried all day to get it to Vapor lock like it used too,, nothing.. purred like a pair of kittens.
This wasn't a cheap fix but it was a permanent fix,, After the first motor the second one was easy. It also cleaned motor up with VST and mech. fuel pump gone, much easier to get to everything now including distributor etc..
Now when someone says hit it,, I'M GONE! no more wondering if she's gonna die on me..
http://www.offshoreonly.com/forums/g...ck-issues.html
YES I did the return line to the tank thing, and the checked the valve / spring on the VST. I moved my water fuel separators, bigger new AN fittings and braided lines. All helped but still would Vapor-Lock from time to time..
I finally finished with gutting the entire VST and Mech. pump mess. What a dumb idea that was.. I added 2 Aeromotive marine pumps, 2- 5 micron leaving fuel filters and 2- fuel regulators with by-pass and pressure gauge.. Wiring was easy. Making the braided lines was the hardest part..
I added rubber feet to the pumps which made them 2/3rds quieter. My motors like to be set at 38PSI.
The fuel rails were sent to Eddie Young where he makes it so you feed fuel at both ends of the rail and he mills and adds fittings so you can add your own AN fittings not that special stuff Merc. uses only. He also opens up one injector passage so not as restrictive. I sent Fuel injectors out to be tested and cleaned since already out and older and never been touched since 97.
[ATTACH=CONFIG]523020[/ATTACH]
I figured might as well test it if I'm going to test it.. So I ran her for an hour and didn't let it cool down and shut her off with no bilge blowers and motors hatch down. Had a brew with some tunes and waited about an hour so she would heat-sink to the max in the sun.. They fired right up with no hesitation. In fact it runs better than ever and my mid-throttle punch is way better now too. I tried the same thing with idling for 40 min. Every time all weekend long fired right up.. The pumps are actually cool to the touch, they don't get warm at all. Tried all day to get it to Vapor lock like it used too,, nothing.. purred like a pair of kittens.
This wasn't a cheap fix but it was a permanent fix,, After the first motor the second one was easy. It also cleaned motor up with VST and mech. fuel pump gone, much easier to get to everything now including distributor etc..
Now when someone says hit it,, I'M GONE! no more wondering if she's gonna die on me..
05-06-2014, 10:21 AM
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I'll get some pic's of the layout next time we're down at the lake. I mounted everything to the bulkhead behind the seat in simple straight lines.. easy to get to now.. and I carry one spare pump that can be changed out in 15 min's if need be.
The stock merc water separators/ fuel filters seem to be flowing just fine too.
Again just so glad to not have this F-ing issue anymore.. Those of you out there know exactly what I mean....
The stock merc water separators/ fuel filters seem to be flowing just fine too.
Again just so glad to not have this F-ing issue anymore.. Those of you out there know exactly what I mean....
05-06-2014, 12:41 PM
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Yes, I dealt with this on the old boat with single 502MPI. I'd like to see pictures here for others to reference. It is a complete buzz-kill to your day when vapor lock occurs. My wife was scared to take the boat out until I got it fixed (mine was a cool fuel setup).
Good luck and I hope it continues to work for you!
Good luck and I hope it continues to work for you!
05-23-2014, 08:37 AM
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SILENT,
Did you use any kind of RETURN/RECIRC LINE from the regulator bypass or from the fuel rail? Or just a single dead ended line at the fuel rail?
My 502's manifold pressure adjust the fuel pressure regulator with a vacuum line from the manifold. Pressure is up with less vacuum and down with high manifold vacuum. I wander if that is not really needed, and just set at 38psi like you did. It's around 42 at low vac and 36 at high vacuum. Maybe it will run too rich/lean if stays at one pressure. The computer may set fuel based on these settings.
Mine is the CoolFuel setup. It recircs from the elect pump back to the filter but still vapor locks probably because its all mounted on the motor.
Did you use any kind of RETURN/RECIRC LINE from the regulator bypass or from the fuel rail? Or just a single dead ended line at the fuel rail?
My 502's manifold pressure adjust the fuel pressure regulator with a vacuum line from the manifold. Pressure is up with less vacuum and down with high manifold vacuum. I wander if that is not really needed, and just set at 38psi like you did. It's around 42 at low vac and 36 at high vacuum. Maybe it will run too rich/lean if stays at one pressure. The computer may set fuel based on these settings.
Mine is the CoolFuel setup. It recircs from the elect pump back to the filter but still vapor locks probably because its all mounted on the motor.
