View Single Post
  #9   Report Post  
Jason Bourne
 
Posts: n/a
Default mercruiser backfiring, destroying distributor caps

dave wrote:

As a non mechanic I'd suggest getting new sparkplug wires (radio
suppression
type). There is a resistance
in them to RF so that they don't radiate. This RF resistance will reduce
the peak current and maybe extend rotor and cap life. Beyond that I'd
guess
maybe a bad connection or bad electronic module. One would be hard to
find and the other expensive.
I'd schedule an appointment with a mechanic that has a automotive scope.



Thanks. All of that has been done! That's why it is so frustrating.


Greetings:

It certainly sounds like you have really looked into the problem and
I seriously doubt if I have any solution, but I thought I'd mention an
experience a friend of mine went through. He had serious pinging issues,
and by the time I got down to look the problem was easily located. When I
went to put the rotor back on after pulling for inspection purposes, I
noticed it rotated in the forward direction almost all the way to the next
contact. Upon turning it over and shining a light there was no key inside.
The plastic key had worn completely off from contact with the metal
distributor shaft. In this case, new rotor meant problem solved. A new
rotor will fit tightly on the distributor shaft. Check to see if the rotor
is loose on the shaft after seeing the problem. If it is something
(vibration most likely) is causing an accelerated/premature wear.

Another thing we used to do when high energy ignition systems first
came out was to put a tiny little dab of silicone grease on the part of the
rotor that rotates to distribute the spark in order to quiet ignition noise
in police/fire radios.

As far as high energy is concerned I'm also wondering if an
excessively high voltage is presenting a destruction that resembles
corrosion. A couple of wild guesses here on my part, but it does sound like
you've covered all the bases already. One thing I do in a situation like
this is employ reverse logic. If I can't figure out what the problem is I
then try to eliminate what it isn't. Sometimes you get lucky and back
yourself into a corner where only one "problem" is left. Good luck to you!

-Jason