'89 135 Black Max--Poor spark on Cylinder 2 and 3

[clove]

In an effort to fix the random stalling I went out and bought a spark tester. All but cylinders 2 and 3 had good spark with at least a 3/8" gap. test was done while cranking the engine. I assume that 2 and 3 are bad so I ohmed out the coils and all appears to be OK. What else would cause these two to be weak? Looking at the wiring diagram my guess is either the stator or the trigger? Not sure. Any advice is greatly appreciated.

 

[Coolmaker]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Switch the switchboxes first and see if it moves to the othr side, if so replace that switchbox.

 

[KCLOST]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Switching the boxes will not result in anything different in this case...<br /><br />Cylinder 2 is the second cylinder down from the top on one bank and #3 is the same on the other...<br /><br />However, a weak spark on #3 can cause an alarm to sound as I believe that the fuel pump rotation sensor is measuring off of that switchbox connection... If that is the case (you can folow the lead from the switchbox to the alarm module to confirm this), it would indicate a bad switchbox...

 

[KCLOST]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Let us know before you spend any money...

 

[clove]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Thanks for all the help. It wound up being the switch boxes--according to the marina. They indicated checking the stator and trigger and those were good(thank goodness). The marina will only use Mercury parts(ouch!!!!) which will cost ~$200/each on top of their labor/time. I would like to say that I helped them trouble shoot this and as a result would appreciate a discount on their labor but not sure how they would take it. Either way, I should have the boat back in a few days and will report back on the performance.

 

[KCLOST]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Good to hear, but if you still have the chance I would buy the CDI/Rapair boxes... You can get them from Seiler Marine for about 140 Each...<br />Easy to install...<br />Good luck...

 

[clove]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Just went to the marina yesterday to check on my boat. They said the switch boxes had not come in yet and they ordered them exactly one week ago. Is Mercury this far behind on these that they take longer to get than standard maintenance parts? Just curious.

 

[clove]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Just got back from the marina. They got the new switch boxes installed--all works great! However, changing the boxes did not get rid of the constant buzzing--even when the motor is off. They are thinking it's a warning module--they are getting one in and should be here tomorrow. How often do these go bad and what chances are there that the faulty switch box took this module out?

 

[KCLOST]

Re: '89 135 Black Max--Poor spark on Cylinder 2 and 3

Constant beeeeeeeeep, equals overheat condition...<br /><br />And has nothing to do with the oil pump unless it is actually overheating from lack of oil...<br /><br />Switchboxes don't normally take out alarm modules...