Re: mercury 135hp spark
The switchboxes are located on that side as you described. There are two of them(one located under the other) <br />The ignition system consist of these basic components. Flywheel, Stator, trigger, switchboxs, and coils. Stator and trigger are located under the flywheel( the timing advance is attached to the trigger)<br />----------------------------------------------<br />This ignition system is plit into 2 induvidual sections (well, almost)<br />1)one section of the stator and 1 switchbox drives one bank of cylinders and the same applies to the other side, or bank.<br />---------------------------------------------<br />2)The trigger has three sections, or coils(like the coils in an alternator), with six wires that service both switchboxes. Each trigger section(or coil) services one cylinder on each switchbox, hence the two wires per section<br />---------------------------------------------<br />You really need a book to explain this and unravel the color code of the wire system.<br />---------------------------------------------<br />Signals from the stator and trigger come together in the switchboxes and this sets the timing and provides the fire signal for the cylinder coils. A bad stator will cause your problem and you should ohm out the stator, and trigger just because, as per instructions in the manual. Trigger will cause you to loose one cylinder on each side.<br />-----------------------------------------------<br />Don't try to crank motor with switchboxes ungrounded. you can see the ground wires connected to the bottom of each box. You may have a bad ground that is just loose.<br />------------------------------------------------<br />You may want to try and swap places with the switchboxes and see if the problem moves with the box. Didn't work for me on mine but 2 new switchboxes sure solved the problem. My motors are strange anyways, or should I say plagued.<br />----------------------------------------------<br />Hope this helps. how much fuel does your motor use anyways? what size boat? Do a search on 91 135 and look at my post on here.
