90hp 2stroke power cutting in and out at wot

I have a 98 90hp 2 stroke, that is acting up, it seems to mainly do it at wot or near wot, and the best way I can describe it, is that the power is cutting in and out, not drastically but very noticeable, not like it's going to die but more like the dropping the rims but a 1000 or so on and off like a switch. Also the tach is going crazy at the higher revs so I think they might be connected, it seems like it's definitely electrical either way. I crushed a spark plug wire in the cowling when I first go the engine, and it was shorting out to the block, as well as shocking be if I touched the cowling or the ignition switch, so I'm wondering if I could have fried something. Anyone have any ideas? Ways to diagnose it without having to go to the lake to see if it's fixed?

You either have a fuel issue or an ignition issue. I would try to cut the problem in half by eliminating one or the other. I am inclined to agree that it sounds like an ignition issue. I would get the mercury service manual for your engine and do a test on each component of your ignition system to find the culprit. It could be a bad coil, switchbox, or stator. Hard to just say yes that is bad coil without running the tests. Would just be guessing.

I will have to look for a service manual, couldn't find any real links to download one online, I'll keep looking though, or maybe just have to buy one. Would the tach going crazy be a indication of what it might be? I was thinking that might point to the rotor being bad, I also got a inline spark tester, I was think of using that to test the coils individualy, but I would need to Rev the engine up with the cowl off. The engine has a sticker saying not to Rev past 3000 without the cowl, is it actually risky to do that?

Depending on your exact model the tach will be (fed) by either a regulator or rectifier that itself is fed from the charge portion of the stator.

The stator has two basic sides, components (chose your term) - one part provides the power for the ignition side of things (so feeds the switch box(es) or CDI coils and ultimately the spark plugs).

The second half of the stator, which while "co-located", not "physically separate" provides the power to the regulator/rectifier to recharge the battery, power accessories or whatever, but is, in practicality, "independent" of the ignition portion of the stator.

If the "charge side" is defective that does not necessarily affect the "ignition side". However, often, if one side gets damaged it can cause enough of an issue to damage the other side of things.

So, your "bouncing tach" MIGHT be indicative of an up-stream issue with the charge stator which in turn MIGHT be indicative of an issue on the ignition side of the stator.

Having the ignition tested can take care of all the "mights" in pretty short order. And given that most ignition components are not "cheap", with the pricetags sometimes in the the "hundreds" (plural) of dollars, this is not a "swap and see what happens" type of exercise.

I got a fsm for the motor, and went to check the stator, and the wiring to it does not match up to what I have instead of red, blue, two yellow and a black wire coming our of the stator, I have two yellow, white with green stripe, green with white stripe, white, white with black stripe, and black wire coming out of the stator. The two green wires are going into a box (first pic) thats not shown in the FSM, and a blue wire coming out of it is going into the switch box. The white, white with black stripe, and black wire are going into the switch box. The red wire coming from the switch box doesn't have anything hooked to it (2nd pic) anyone have any clue what's going on here? I'm guessing the previous owner tried to use a stator that wasn't meant for it and did a hack job installing it. This is a new to me engine, and I don't know if it was working correctly before I got it.

On closer inspection what I was calling a black wire is actually grey/brownish and that wire as well as the two white ones and a purple one are coming out of the center of the stator, which I assume is the trigger, so it looks like that part of the circuit is correct and it's just the stator that's messed up.

This is the wiring diagram from the FSM

Your manual is for an earlier model - the stator colours you see are correct for a 1998 CDM model.

From the stator you should have the two yellow which connect to your voltage regulator;

The white with a green stripe feeds the CDM/Coil for the number one cylinder.

The green with a white stripe should go into a splitter and split into two separate green with white stripe wires - they feed CDM/Coil number 2 and 3 respectively.

The Purple, White, Brown and Black wires come from the trigger.

The stator changed in the 1997 model year. If your manual shows the stator with the red and blue stator wires it is for 1996 and older models...

***** if you have the entire manual for the couple of pages you posted up, go down a couple more pages to page 2D-15 - it will have YOUR electrical system.

I was using the diagram based in the serial number of the engine, also the rest of the diagram seems to match my engine, the 98 one doesn't. My serial number is 0G14xxxxx I'm thinking they tried to make a 98 stator work on my motor, I think I need get a 95 stator. I put the wrong year for my motor in the original post.

Yes, that serial would make it a 1995 model with a T4 ignition, not a CDM ignition.

So I should probably just go ahead and replace the stator with the correct one, right? There's no way that it could work correctly with that stator, right?

I talked to a outboard mechanic today at southcentraloutboards that had a used stator for sale, he seemed very knowledgeable and helpful. That box that isn't in the wiring diagram (pic 1 above) is a adapter to use the red stator on a black stator engine. The fsm I have actually has a section for diagnosing that stator that I didn't know it was for my engine before. I wrung out the wires and the stator seems to be good ohm test is in spec... (well slightly high 730 instead of 710 between the green wires but I think that's just resistance in the connector) but the voltage while cranking is low, although not super low 135, min is 190, according to the fsm this means the adapter box is bad, does this sound right? It seems to run fine, wouldn't it run badly if the voltage was low at cranking speed?

Wanted to say seems to run fine at idle, in the above post, don't see a way to edit it.

A bad stator adapter will cause it to misfire....

Red stator kits are usually pretty reliable. Is your battery charging? Could be a bad voltage regulator

I will disagree with the red stators being reliable....

So I tried changing out the adapter, and no change, is it possible the stator could be bad, even though it ohm checked good? The battery is charging fine, as far as I know. The voltage comming out of the blue wire off the adapter is still low, at cranking speed, and jumps between zero and max on my 1000 vdc setting on my meter.

Run with a tinming light hooked to one cylinder at a time.--------See how spark behaves .-----Might help pinpoint the trouble cylinder.

Like a normal car engine ignition timing light? Or a in line spark check light? Anyone know what's up with the sticker on the motor saying not to run it without the cowl above 3000 rpms? Doesn't act up till above 3000 so I'm guessing I would have trouble isolating the problem, that way without reving it higher without the cowl.