age old ?,how to stop vapor-lock,vst system

[bcfountain]

i know you guys get tired of reading these same old posts,but i need help.1994 502 mag,efi.after running hard for awhile and when i shut down for more than a hour,my engine will vapor lock.it will start ok and idle,but when i go to get on plain,it will spit and chock,and then clear up.i have r/r the mech.fuel,cleaned/flowed the injectors.temp is about 140.where is the vapor lock at?the mech.pump,lines,or high-pressure pump?i would really like to keep fuel injection,but a carb is looking pretty good right now.anybody?thanks

[Von Bongo]

Per Mercury Tech Bulletin from a few years ago.

· Let the engine idle for 3-5 minutes before shutting it off.
· Opening the engine cover to let the hot air escape.
· Operating the bilge blower to remove the hot air.

To my knowedge there is no 100% fix for this.

[UNCLEJOBIN]

Mercury had the same problem with the 575s early on. The problem was most evident with "Winter gas". Is this when you have problems? If so there was a kit to correct this problem. I think the kit had a check valve along with some other items. If it helps I may be able to find the kit number. Mercury only installed the kit AFTER the customer reported problems. Hope this helps.