Need help with Loss of Power
brad wrote:
Several years ago I experienced symptoms very similar to what you are
describing in my Mercruiser which was four years old at the time. It
certainly seemed like a fuel issue to me, and that's where I started;
anti-siphon valve, fuel pump, etc. The problem persisted; loss of
power at higher rpm only, after warming up only. Idle was fine. Then
I turned it over to my local pro, and he too was stumped for a while,
ended up getting the factory rep involved. Turned out to be an
ignition problem: specifically the "stator." Must admit I'm still not
sure what that is, but it did solve the problem. But I learned a
lesson about seizing on an assumption (fuel-related) and not keeping
an open mind to alternatives (ignition). Hope this helps, good luck.
[snip]
Greetings:
FWIW: The stator is the inductive pickup inside the distributor
of a system using an electronic ignition. It is essentially a pickup coil
that senses when a magnet comes near. The magnet is being rotated by it on
the distributor shaft as it turns.
There exists a similar failure mode to the regular ignition coil in
that sometimes there are intermittent internal shorts when hot. What happens
is that the insulation breaks down and allows some of the windings to short
out. The pickup unit inside the distributor is sealed with potting
compound, but can still exhibit this type of failure. It can be very
difficult to pin down.
The problem with nailing this is that the best way to troubleshoot
involves an ignition analyzer scope that can monitor the "dwell" period.
Think of the dwell adjustment on an old points type system. This dwell
period is what the pickup coil inside the distributor simulates. You will
only see this on the scope during the period when the problem is
manifesting itself, ie - not too many people are out boating with a scope
hooked up! :-)
It may or not be related to the particular problem at hand, I just
thought I'd throw it in for background. Good Luck to you in any event!
-Jason
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