Testing mercury stator

I have a Mercury 4 hp single cylinder that has no spark. I filed the points, soldered on new wires as testing mercury stator insulation was cracked. I had spark initially and then nothing.

I get conflicting numbers all over the internet on what its supposedto read. I have this stator off a 3cyl force.. On the yellow circuit i get 1 ohm. Be advised that on many Mercury stators, there is a high and a low speed circuit. This one is no different. There are different readings for 90 and hp, 3 vs. The 3 cylinder 90 has only a red and a blue wire, not pairs of red and blue.

Testing mercury stator

My starboard motor has had poor acceleration past 2,RPM for a few weeks. I had changed all filters, changed separators, changed spark plugs, cleaned final filter, ran alternate fuel tank, and still no solution. Each motor has two of these. Try swapping one from one motor to the other. If the trouble switches sides with the switch box, that is your problem. This is a very common failure. I suspect dirty injectors. If you find a dead hole, swap the coils over to the other engine all of them. If you have fire for each hole then I would have the injectors cleaned. There are drain hoses on each side of the bottom of the block in the bottom of the cowl, make sure they are there and not worn out or broken off, what was happening to me is water was coming up threw the holes from the bottom of the cowl and would short out the bottom 2 cylinders, When you dropped speed the water would not come up and the plugs would dry and fire again. If you look at a diagram you will see these short little drain hoses that I'm talking about. You can generally make a static test of a coil winding by checking its resistance, and checking any resistance from the coil to the chassis in which the coil is mounted. Most coils are made to be completely insulated from the chassis in which they are installed. You can make a dynamic test of a stator coil in a permanent magnet alternator by measuring the alternating-current voltage that is produced by the coil when the permanent magnet alternator is rotated. Usually there is a load associated with the test, and you may have to fabricate an appropriate load.

Thanks for your help guys and gals I really appreciate it.

Testing my stator using a ohm meter my readings are. Between blue and red leads Also does the stator have to be installed on engine for this test and is this a good test procedure? If your readings are not within the range specified for your stator the part is bad. Replace it.

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Testing mercury stator

Your outboard stator is the "powerhouse" of your outboards ignition system. Most Mercury Outboard Stators perform two important functions 1. They provide voltage to your switchbox or CDM's.

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Chris Supreme Mariner. To use it you must have the newer style voltage regulator that has five wires, not the older one with three wires that attach to the regulator. My first and second set of readings Of course, to measure the resistance of the coil and the voltage produced by the coil in the stator when the permanent magnet alternator is rotating and compare it in a test you will need some standard resistance and voltage measurements. This one is no different. An engine that is running too hot will "overheat" the stator. They charge your vessel's battery s. If you need anything at all, I check my email at least a couple of times a day during the week. There are different readings for 90 and hp, 3 vs. So, while I'm sure the low speed winding helps with low RPM charging, it apparently also has the primary role in supplying spark to the motor. I'm gonna check the lines later. October 17, at am That will remove the ign keyswitch and wiring from the test.

Are you noticing anything wrong related to the battery and engine?

Joined Jun 26, Messages 14, Engine fails to run and has no spark. Ran real well. In a permanent magnet alternator the voltage output of a coil is proportional to the engine speed, so as the engine speed increases the output voltage rises. I did not use my hand to pull plug wires, I used metal insulated pliers. When we got back in the bay it ran well. Thank you for the article. A great thing to have in my box. Chris said:. In general, there are two types of tests. Thanks so much. Put a timing light on one plug wire at a time and slowly take it up to RPM looking into the timing light. Join Now!