HELP 2001 5.0 EFI 240hp

[Ididntdoit]

OK - back on helping my buddy with his crownline again.....Runs great cold - crank no start or crank start sputter and die on hot restart.......classic vapor lock symptoms - why now, out of the blue? how do I test fuel pressure on this model? what should it be? How do I "cure" the vapor lock on this model? Any known fixes? Could this be somthing other than vapor lock? I remember reading about ignition modules getting hot and not working - also remember reading about a "phantom" interrupter switch issue on here, but can't seem to find the thread....trying to help him get the boat ready for vacation next week.....

 

[ColoSR]

Mercury has a tsb for vapor lock, it has some answers for you (below). Blower and idling before shutdown are the operational items, a helper pump and or a bigger water intake get rid of it as well.

https://stu-in-flag.net/blog/wp-content/uploads/2014/08/vaporlock.pdf

 

[Ididntdoit]

thanks - I passed it along - i do remember people having to add pumps

 

[Ididntdoit]

thanks for the kick in the ass on this - he last filled it in early april with super.....likely still "winter mix" - i had him run the boat on plane for an hour - this ran some of the old fuel out and warmed it up - i then had him idle back to the dock with the engine cover open and the blowers on and.......voila problem gone - hoping once its full of fresh summer gas, the extra steps are not necessary

 

[scoflaw]

Sounds like it's running hotter than normal. Pump is old, manifolds partially plugged, timing a bit off.

 

[aerobat77]

as a first no cost try :

run the bilger blower all time the engine is running and keep it running some minutes after shutdown.

i found out this reduces massivly the heat in the engine bay and might solve his problem.

 

[Strecker25]

to comment on the ignition module (ours is basically the same motor, 98 5.7efi) mine was getting hot under load and cutting injectors and spark. It is located under the distributor cap and can be easily replaced without even pulling the distributor. Part is about $100

As for fuel pressure, best way is to buy the TBI schrader valve adapter to hook up to your fuel pressure tester. You could probably fashion one up, but the merc part is about $75