2000 Searay vapor lock

mmarincic

Seaman Apprentice
Joined
Sep 2, 2008
Messages
35
I have a 2000 Searay with a 350 Merc. After I run it 30 minutes or more it will vapor lock in the fuel filter and I have to remove the filter and fill it with fuel before it will start. Does anyone have a fix for this
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
That isn't a vapor lock, it's a lack of fuel. I would check fuel pressure for starters.

Need know which 350 Merc.
 

Rick Stephens

Admiral
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Aug 13, 2013
Messages
6,118
Usually impossible to vapor lock a boat. Unlimited cooling,,,. sounds like an air leak in a fuel line or a plugged up anti-syphon valve.
 

Stinnett21

Chief Petty Officer
Joined
Jun 24, 2012
Messages
549
My 2002 5.0 MPI would do this. I discovered it was the check valve assembly (part #21-864206A). The internal valve had come apart and I believe it was allowing hot water from the block to back fead into the fuel cooler. This would happen on occasion after sitting for 30 -40 minutes the boat would turn over but fail to start as though it was starving for fuel. Before I discovered the bad check valve I would loosen the fuel filter looking for a solution and this would seem to help a bit. Replacing the above part is what fixed it. Not sure this applies to yours. My 2 cents.
 

mmarincic

Seaman Apprentice
Joined
Sep 2, 2008
Messages
35
I have a 2000 Searay with a 5.0 merc. After cruising for awhile and slowing down to no wake speed it will quit and I have to remove the fuel filter and add fuel, It will be down a couple of inches. I have even ran the intake line for outside air down next to the filter and ran the blower while cruising. Has anyone else had this problem
 

alldodge

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Staff member
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Mar 8, 2009
Messages
42,542
Filter should always remain full
Either a pump problem or a restriction
 

mmarincic

Seaman Apprentice
Joined
Sep 2, 2008
Messages
35
My 2002 5.0 MPI would do this. I discovered it was the check valve assembly (part #21-864206A). The internal valve had come apart and I believe it was allowing hot water from the block to back fead into the fuel cooler. This would happen on occasion after sitting for 30 -40 minutes the boat would turn over but fail to start as though it was starving for fuel. Before I discovered the bad check valve I would loosen the fuel filter looking for a solution and this would seem to help a bit. Replacing the above part is what fixed it. Not sure this applies to yours. My 2 cents.
Thanks for the help but Where is this check valve at.
 

Stinnett21

Chief Petty Officer
Joined
Jun 24, 2012
Messages
549
Mine is #2 in the attached. Port side low and back. Yours may be entirely different.Screen Shot 2021-04-06 at 8.12.38 PM.png
 

LWD

Seaman Apprentice
Joined
Aug 2, 2011
Messages
46
My 2001 SeaRay with 4.3 EFI vapor locked, I struggled with it for a couple years, took it into a couple different boat shops, then I ran across this TSB on the internet. I installed the check valve mentioned in the TSB and adjusted some of my habits, such as not shutting the engine off right away, and running the blower motor before shutting off the motor.

Basically what was happening, when it was hot and shutting down the engine, hot water was back flowing to the fuel cooler and causing vapor lock.
 

Attachments

  • Mercruiser Vapor Lock Bulletin.pdf
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Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,726
This is a 5.0 305 CID. Thanks for the replys. I'll check everything
What the guys are looking for is an engine serial number or is the engine carb, efi, or mpi the answer you get will depend on what fuel system you have
 
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