BUP

iTrader: (9)

^^^^ what is said here and the vapor lock problems. Man I have seen stuff growing in those VST tanks - You have a needle and seat persay with a float along with a fuel filter in the bottom and the high dollar fuel pump among other related parts in that system living in today's fuels - with that said not good things happen inside especially being a 20 plus year old system & set up.

Anyways the gen II cool fuel is much better and so is MEFI 3 or even MEFI 4 if you can get a great tuner person for it.

We have done many carb conversions in past as well for the owners because mainly of a couple reasons, related costs and some even had ECM issues. A lot in my area had vapor lock issues to.

I am sure that it has been posted up here about some of these VST's have related back to engine failures and even hydrolock issues. Surprise no one has one posted currently.

the holley MPI conversion looks good for this as well.

IMO if you have parts replacement needed for the VST and or possible ECM driver issues ( MEFI 1), - I would do some sort of conversion especially a more current conversion option or a carb conversion for a cheaper route.

In my area again Vapor Lock was a huge issue as well even when brand new.

there was a reason that Mercruiser had this VST app around for only 3.5 years and quickly moved on to gen II cool fuel. . just saying

SB

iTrader: (1)

Not to push it, but carb conversion is easy. Keep the mechanical pump and keep the same distributor even. Some people pick up speed too.

Or as Bup has also mentioned, run a more conventional fuel system.

92nsx

FIxing the vapor lock is easy and cheap also I have 0$ into mine (had the parts in the cabinet form other projects I have a write up on here.

Cliff notes:
The diagram fails, when it dose it can hydrolock, wash down cylinder, thin out oil, ect since it dumps the "over filled fuel into #8 piston.
Mine failed 2 times in 2 years
In stead of having replacing it for $90 every year, have that clear(ish) line back to the tank vs #8.
Now when it fails (witch is a good thing) It send the fuel back to the tank. Thus also cooling the fuel.

Mine has been this way for 2 years. No more fuel problems here. (But i also play it safe, open the hatch 6-8" when idling, run my blowers any time the engine is running, once anchored of at the sand bar, I leave the hatch fully open for 5 min.)

http://www.offshoreonly.com/forums/g...work-pics.html

BUP

iTrader: (9)

http://www.boatfix.com/merc/bullet/93/93_02.PDF

BUP

iTrader: (9)

http://www.boatfix.com/merc/bullet/93/93_26.PDF

Back in the day there was always a problem with the system. And then the fuel started changing causing different issues. Just saying.

You are running in MN come down here when its 105 plus degrees for months and no shade with the lake water temps sky high. Run you engine like most boaters, no blower on and not venting the engine hatch ever. Run for a 30 to 45 min WOT and then shut your engine down to take a break for about 2 or 3 hours. What no start ? very common here.

AllDodge

iTrader: (1)

Mine vapor locked only twice but each time is was a real hot day, and didn't let it cool down enough (just maybe) but IMO the thing that helped more then anything was non-ethanol gas. Either way the real fix seams to always be to run the return back to the tank instead the VST or filter. Indmar seams to have done just that on their motors, don't know why Merc doesn't

BUP

iTrader: (9)

All Indmars currently run all fuel pumps in the gas tank and this has 99 % cut out VL, Also some in past years depending on boat manu - Mastercraft has done this for years fuel pumps in the gas. just saying.

92nsx

Easier install of engines for OEM's. Just 1 fuel line and a harness.