As you may recall, in early 2006 I started a thread about the flooding
QJet on Cruis'n Rulz! 5.0 Mercruiser. After replacing the foam float
w/brass and overhauling the carb, the flooding on start-up continued.
Multiple carb top r/r and float resets failed to solve the problem. At
last, it seemed to correct itself, and ran normally. I didn't get out at
all in 2006, due to medical problems (broke my pelvis). Now, Mar 2007, I
start to recommission. Fire it up on the muffs, and guess what-you
guessed it. Gas washed cylinders and again, flooding carb. I decided NO
WAY it was misadjusted, and the last time I tore it down, I checked the
needle and seat by blowing into the seat while gently holding the needle
seated. No leak. I decided the fuel pressure MUST be too high, although
I was assured in my thread of 2006, the Mercruiser mechanical fuel pump
does not have a pressure regulator built in. Attaching my low gauge to
the fuel inlet pipe and cranking the engine, it pegged the gauge at 10 PSI.
3-5 PSI is max for a carb, as anything higher will unseat even a new
needle/seat assy.
So, Now I find the fuel pipes are corroded solid to the flare nuts and
just twist off with the nuts. Everything around the fuel pump is badly
corroded, due mainly to the 2003 partial sinking at the dock when I left
the drain plug out when launching.
See it he
http://www.seanet.com/~jasonrnorth/bp1.html
Now I get to replace the fuel pump AND water separator.
SOOORY for the long, boating related post. What a waste of bandwidth Huh?
The point: Mercruiser mechanical fuel pumps do indeed have an internal
pressure regulator, and, they can fail. Said failure can cause MAY hours
and bux wasted trying to resolve a flooding carb.
FYI
JR


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Home Page: http://www.seanet.com/~jasonrnorth