[Spridgets] Mercruiser 4.3 Choke and Startin Procedure

Richard Ball richb at u.washington.edu
Wed Sep 3 21:48:50 MDT 2008


My dad is a Mercruiser mechanic here in Seattle, so I just asked him about
your friends problem.  The first thing he asked was whether the engine smoked
black smoke when it started or not.  Apparently the 4.3's all seem to run
rich.  If so you need to lean out the electric choke.  More on that later.

The starting procedure is as follows.  With the engine off move the shifter to
neutral and disengage the shifter from the throttle with the lock button below
the shifter.  Move the throttle forward and then back to center like you would
tap the accelerator on your carbureted car before starting.  Move the throttle
slightly forward of center again and crank the engine.  It should start.  If
not go through the procedure of tapping the throttle forward three times in
quick succession.  then move the throttle slightly forward and crank again.
You can flood it if you move it forward to many times, so only use three if
you have to.

OK back to the choke.  To lean out the choke loosen the three screws holding
the black plastic disk to the choke body(Torx 15 if memory serves?).  It
should be marked rich and lean.  Rotate towards lean until the butterfly is
almost closed. The pointer mark will probably be off the scale, but that's OK.
This of course has to be done on a cold engine.

If it doesn't smoke and is not running rich then you need to look at the
timing.  This engine may or may not have a knock sensor, so He should pick up
a service manual before taking that on.

Remind your neighbor that this is not his fuel injected computer controlled
car, but still has a carb and need a little finesse to start.  Also, if he is
new to boating tell him to get that thing winterized BEFORE the weather
freezes.  Exhaust manifold risers are EXPENSIVE (several hundred a piece) to
replace and crake easily if not drained properly.

Rich Ball
'76 Midget
Everett, WA

My next-door neighbor just bought a 93 Sea Ray with a Mercruiser 4.3 V6
engine.  He has had a heck of a time starting it but once he does get it
running it runs good.  He called me tonight thinking that I might help with
the problem.  We centered on the electric choke and I think the problem is
in the driver seat.  He doesn't have a manual so we don't know what the
procedure should be.  It looks like the throttle should be disengaged from
the shit mechanism with the unlock button below the engine control.  At the
first detent the choke seems to be free to move mechanically and if cold the
electric choke servo should move the choke butterfly.  Can anyone confirm
what the starting sequence should be, are we getting warm?  It is a Alpha
One Chevy based V6, 2 barrel carb with a Thunderbolt ignition.  I can't seem
to find anything on line about operating the engine.

Help,  he is taking his family to the lake tomorrow evening for a long


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