I have the same problem with my 1972 Evinrude. I thought I had cured it
with a new Amplifier (CD Unit) but it came back. I have replaced plugs,
wires, coil and AMP. Now I am diving into the carbs to make sure
they're clean. I have also read that some outboards with bad lower
seals can vent exhaust back into the intake (try running without the
cover to diagnose) causing this problem once the engine warms up.

It was suggested to me that I run the engine in the dark to see if the
spark is jumping where it ought not... however I don't have a test
tank, and I can just see myself in the pitch dark down at the lake
trying to work on the engine... I've been told these old prestolite
distributors/rotors are famous for leaking spark (even new ones can do
it.)

I have meticulously cleaned my distributor (in my case it's under the
flywheel) and rotor and now am going through the carburetors. I sure
hope I find what's wrong soon. My engine runs and once the boat's on
plane it runs great... but under load it really complains- feels like
two out of four cylinders are missing.



AllStar Entertainment wrote:
Help with boat problem
----------------------------------------------------------
I have a 140hp Mercruiser engine in a boat I just got ,,I was wondering if
I could get some advise???

My boat runs great for about 1 hour,
however as soon as I start allowing my
kids to ski or tube , and I go from drive to neutral , and back to drive a
few times the boat wants to die.. like it is running on 2-3 cylinders, not
all 4....

I was able to run the boat fine with , the problem seems to only happen when
I go in and out of drive several times and when the boat has ran a while

I changed the neutral safety switch on the side of the engine.. ( I was told
that was the problem) but it still does the same thing... any idea's
I do not believe this is a fuel problem

Depressed in Apex