I was on my third outing of the season...running fine in the 3-4k range when I began smelling raw gas. Stopped the boat, checked the obvious and found nothing unusual. When I started the boat idle was rough and raw gas was pumping through the exaust.

I've changed plugs (a little carbon but not too bad) and run injector cleaner through the fuel sytem without improvement.

Any suggestions?

Sounds like fuel pressure is too high. You can put a gauge on the system and check it to factory specs.

What year and does it have a VST tank near the dist.? If so when the valve in it sticks it will pour raw fuel into the intake and cylinders. Worse yet is the fuel will wash down the cylinders and into the crank! Check your oil and change it. Gas is not a good lubricant.

It's a '93 502 EFI Magnum.
VST tank?
What does VST stand for?
Any idea what factory spec is for fuel pressure?

Thanks !!

KenD,

VST=Vapor separator tank.

Fuel pressure at injector rail should be 38 psi @ idle.

Mark S.

"Vapor Seporator Tank" Follow the fuel line from the mechanical pump to it. It is located next to the distributor. It has the hifhpressure fuel pump in it. There is a clear/greenish hose off the top of it to the underside of the intake manifold. When the needle seat is leaking the extra fuel overflows and dumps into the intake. You can rebuild the VST and solve your problems. Don't forget about the oil. Don't be surprised if the level is high.

I am confused if its an EFI motor why would he have a mechanical pump.

you actually have 2 fuel pumps one mechanical pump on your sea pum, then a second fuel pump is is the VST set up.

Don't buy the new 575!!! They pour gas by the gallons out of the exhaust! The EPA would have a field day with me!! All I smell is raw gas, I feel like a floating bomb! They want them to run too rich so they don't blow up especially under warranty! Good luck. denohew ( Luna Sea )

I checked pressure at the rail and its reading 30#. Also looked for the clear/greenish line from VST to the intake but mine only has a 3/8" black line coming out of the VST marked "vent" on top of the VST.

Good news is that there isn't any fuel in the oil....yet

Back to square one?