Logo

Purging old gas Crusader 8.1L MPI Returnless Fuel System (s/n 670174 & 670175 MFG. 8/2006)

major_tom

Regular Contributor
Hello Team:

I just completed the purchase of a
Blackfin 32 with a pair 8.1L MPIS's up here in NE. There is about 95 gallons of stabilized fuel in the tanks, but its been sitting for 2 1/2 years. I'm having a fuel service clean the single 304 gallon tank and dispose of the old fuel but this won't happen until mid-March.

Just before the purchase both engines were started briefly to "make sure they ran". They started right up on the old fuel but I'm worried about that. I'd like to clear the fuel lines, fuel filters, Fuel Control Cell, etc. starting just before the small pre-filter at the low pressure pump all the way to the fuel rail.

My plan is to:

1. Drain the fuel from the FCC
2. Drain the fuel from the pre-filter and fuel lines at the input of the low pressure pump
3. Disconnect the fuel line at the fuel rail (do I need to be careful about high pressure here?)
5. Connect a 5 gal. tank of fresh gas with injector cleaner. Use a primer bulb and\or key to ignition run to force the fresh gas through the entire system.
6. Run engine for a few minutes on the fresh gas. Probably need to cycle the fuel pump several times with "ignition run" to prime the fuel system.

Am I overthinking this? Should I try and purge the old fuel or just let it sit until the tank is cleaned and fresh gas is available via the normal route?

Best wishes,

Tom
 
Welcome Back Sir!

on the pressure in the rail, most fuel pressure gauges have a 'bleed' function that will allow you to eliminate any remaining pressure in the rail.

you can drain the old stuff out and use the portable tank as described before the service man arrives...just gotta provide some water to the raw water system if the boat is still blocked...and ensure plenty of ventilation...
 
Thanks Mako.

I already pulled the raw water impellors. After flushing out the old fuel I intend to start up for 30 seconds or so on the fresh fuel from a portable tank and then shut it all down until the fuel tank receives a proper cleaning and fresh fuel. The motors are in engine boxes and I'll be sure to run the blowers and clear the air before start up.
 
Back
Top