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Vapor lock symptom

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patrickjreynolds

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I have a 1997 Baja Islander 232 with a 7.4LX EFI-MPI Bravo engine. Right after I purchased it I suffered vapor locking symptoms. I could run all day with no problem, but if I sat and idled for a few minutes it would die when I accelerated. Once I shut off it would not start until it cooled down for hours. I replaced the mechanical fuel pump then rerouted and insulated the fuel line away from the heat of the engine. This helped, however it will now just idle longer period (10 min or more) before dying on acceleration, and it will start up after sitting and then die when I accelerate. There is not excessive heat, I can grab the fuel line and the fuel pump and they are cool to the touch. I have discovered that if I break the fuel line at the Vapor Separator tank it releases the pressure and it starts right up. This is now my work around, I can start back up right away by releasing the pressure in the fuel line. I am unfamiliar with VST's, is the VST causing this problem? Any suggestions would be appreciated.
 
The VST is the problem. You can remove the VST and install a Generation 2 fuel cooler....Or you can install a second bilge blower and have it blow air from the outside the hull directly on the VST tank.
 
Docksidemarineservices said:
The VST is the problem. You can remove the VST and install a Generation 2 fuel cooler....Or you can install a second bilge blower and have it blow air from the outside the hull directly on the VST tank.
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It sounds like there is nothing wrong with my VST then. After a google search it seems the fuel coolers are expensive, additionally I have seen multiple parts from just a tube to a several hundred dollar setup with electric fuel pump. Would the fuel cooler replace my mechanical fuel pump? Do I just replace the VST with a cooler or install a new fuel pump? Given the cost I will attempt a second bilge blower first. Thank you so much for your help.
 
Docksidemarineservices said:
It is $$$$$ to convert to a gen2 cooler. The extra bilge blower will help.
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Thanks for your help! I threaded a few strips of reflective insulation below the bowl and my fan just delivered and is not installed yet. But over the weekend I did not have any vapor locking just from the extra insulation (84 degree day). It would normally vapor lock every time, no matter the conditions. This was the first time I was able to boat without having to bleed the fuel line. I am betting the fan will insure it doesn't happen at any temperature.
 
The insulation is a good Idea. The blower fan will do the trick for very hot days, I would run it all the time.

Not to many of these systems still in service.....

FYI the filter in the VST is Mad money from Mercruiser and may be NLA. The filter from a Yamaha VST (you will have to match them up) Fits perfect. $40.00
 
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