It's all in the Timing...
It will be another generation or so before somebody says, I remember the good old days
when we had points and condensers and a thing called a distributor to make our engines
run..... Until that day there isn't any reason to believe they are going to go away
tomorrow. It will take at least another 15 years to retire 80% of the equipment that is in
the field right now.
It's been a good policy to convert over to electronic Ignition where possible, but the
good marine replacement Distributor Ignition isn't an inexpensive thing to buy, especially
when your doing twins.
As these units age, the customer still expects them to run properly, so learning
some of the basics won't hurt.
The manuals pretty much cover the basics of doing a tune-up so my purpose here is to
remind you that all boat distributors use a counter weight timing advance. Under the
points plate you will see this centrifugal advance mechanism. Look to see it's condition
and that both return springs are clipped in place and functional. They have a tendency to
rust, stretch, and break so make it a part of your tune-up to check to see if the timing
advance is working correctly. The timing advance and return is very important to the
performance yet it's probably one of the most overlooked tune-up operations.
On the average engine, the timing should never move, when the engine is between 500 and
900 rpm, and many shouldn't have any timing advance until 1100 rpm. It's getting tougher
to find a good distributor rebuild shop, but if you see any sloppiness in the timing when
the engine is idling, it's best to have the distributor serviced.
Note: We are referring to mechanical advance
distributors. Timing advance on an electronic controlled ignition will continuously
change at Idle.