Intermittent loss of power (long winded 1st post)

[80Grady]

Long winded post ahead, but I've searched the forums, and read through just about every thread with similar issues. Although theybeen very helpful, so far the cause still eludes me. Took it to a local certified mercury shop and of course it ran great and wouldnt act up for them. You all are my last hope.
Randomly my engine will not go above 3k and will not get on plane. Sometimes it seems stuck like that, other times it suddenly jumps rpms and takes off like someone flipped a switch. It used to only happen every few trips, now it happens almost every time I take it out. Seems most frequent after going slow through a 6kt zone then attempting to jump back on plane.
Q
Engine still intermittently wont go above 3k then like a switch turning on, sometimes jumps up and runs perfectly
Since the previous post, the stator tested slightly out of spec, so I replaced it. While replacing the stator I noticed cracked wires on the trigger harness, so the trigger was replaced too and the timing was checked Problem still is present and seems to be happening a bit more frequently now. I have recently noticed that when it won't go above 3k, it is then physically difficult to get back into neutral? I have to almost force it back. Sometimes it even rev's up when it finally gets into neutral and then drops back down to normal idle rpms after a second or so. When it's running properly, there is no resistance going into neutral and no abnormal rpms when returning to neutral. Any thoughts on this? Neutral safety switch problem? Intermittent faulty driver on the ecu? Something else? Been pulling my hair out chasing this issue. Bought the factory service manual, but still can't seem to find the cause. What I've changed/ diagnosed so far.
Leaning towards bad injector driver on the ECU. or bad control module? (Timing protection module) the service manual says that "The control module provides rev-limit (carb models), bias control, shift stabilizer, idle sta-
bilizer, injector timing signal (EFI models), and low oil warning."
Thoughts? 2001 saltwater 200 EFI

-New plugs, fuel filter and rectifiers
-Verify via timing light that each cylinder is getting spark even when issue is occurring.
-fuel bulb still tight when issue occures
-fuel (gph) via fuel flow meter drops below normal 3k rmp useage when issue occurs.
-Fuel psi at VST port
40-41@ idle and cruise when no issue
37-38 @ full throttle when no issue
43-47 gauge needle bouncing erratically when issue present
Issue seems to occur most frequently after cruising at low rpm for a bit, then attempting to accelerate.
Stator and trigger has been replaced
VST cleaned
I'm completely at a loss. Water conditions have not been favorable when it has acted up and I had tools present to actually check strength of spark when acting up, only via timing light.

[OnPad]

Seems like a common problem with that year. I bought one last year for 800$, (like new). The previous owner dumped a bunch of money into it, and gave up. I haven't messed with it yet. I did do a bit of research and didn't find a good answer. The post's I looked at were not as detailed as yours, just people complaining about not being able to get on plane with a 2000/ 2001. Maybe someone will chime in and come up with a good plan for testing those injector drivers on the fly. Maybe you could wire in a volt meter to a injector, see what happens when it gives you problems. Sounds injector related, if your fuel pressure is going up when it happens. If you figure it out let us know.

[rgsauger]

Welcome to scream and fly, Grady. Good luck in finding your answer. If it was older, I would say check switch boxes.

[OnPad]

So I read your post again, and read a few others on same issues. One engine was fixed with a new fuel pressure regulator another with a injector service. I have a service manual for that engine, when I get some time I will see if I can find something that will help you out.
Your shifting issue is par for the course if your running (lean) excessive rpms, they don't like to come out of gear, or go in.
Check your fuel lines and tank for obstructions also.

[Smalltownbassin]

Possible bad fuel pump driver causing intermittent issues (bouncing gage needle when the problem occurs). You can supply the pump with dedicated power to troubleshoot the ECU driver.
Possible bad pump (usually the ECU driver, not the pump its self but maybe) Same method above will tell you if its either of these.
Weak battery (causes all kinds of gremlins on an EFI) Test it and replace if needed.
Bad voltage regulator (causes strange rpm surging and can fry an ECU if voltage going to battery gets too far out of whack) Test and replace as needed.
That ecu only has 3 injector drivers, one per two injectors. So when an injector driver goes out you typically drop two cylinders and it would be very noticeable. If the injector is getting stuck open it could be flooding that hole and killing power but it would have a noticeable stumble. If the injector is sticking closed or intermittently working, the damage may already be done.
Just my thoughts on it.

[80Grady]

Welcome to scream and fly, Grady. Good luck in finding your answer. If it was older, I would say check switch boxes.

Yup, no switch boxes on this model

[80Grady]

So I read your post again, and read a few others on same issues. One engine was fixed with a new fuel pressure regulator another with a injector service. I have a service manual for that engine, when I get some time I will see if I can find something that will help you out.
Your shifting issue is par for the course if your running (lean) excessive rpms, they don't like to come out of gear, or go in.
Check your fuel lines and tank for obstructions also.

If starving for fuel due to restrictions before the engine, wouldn't my primer bulb go soft?

[Davidlake]

My bet is one or more bad coils. There are more than a few Merc. models that have TSB's regarding defective coils. I have had Opti's as well as 4 strokes behave exactly like you described to find (after hunting fuel, sensor paths) to finally realize that it was coils. Start by checking your spark plugs for black soot.

[OnPad]

Just kind of sounds fuel starved to me with it racing at idle. Fuel hose and tank are a easy spot to look. It wouldn't flatten your bulb if it was above it. That grey marine hose delams when you take it off and on, you end up with a wad of clear plastic in your hose. You can try a portable 6 gal tank just to make sure. For some reason your fuel psi is spiking when you have problems? When I get home I will see if I can figure out how to test those injector drivers, I think you have to use a dva.

[OnPad]

So I did a little more reading, looks like manual ain't going to be a lot of help for backyard driver test, they're saying to hook up to DDT. It also claims that the drivers are run off of switchboxes on that type of ignition system. Working out of a older manual with a supplement for your motor. So they are probably timed off of the trigger going to control module then to ecm on your motor. Shows a special wire adapter to test. Your coils are in the mix there also so that's making a little more sense to me now. Those cdm coils look like a pain in the arse to test. But I did find a easy test for your regulator. Let us know what's up when you get this figured out.

[80Grady]

Haven't noticed any black soot, but I'll go through testing the coils again.
Do you know if a coil could test inspec while static, but then have issue when running? If so, that'll be a nightmare to track. Or I'd have to just replace all and keep my fingers crossed

[80Grady]

No switch boxes on this model. I have a service manual for it, but there doesn't seem to be a direct way to test the control module. It appears that it should be replaced when other components are ruled out. I have a DVA adapter for my meter, but my manual mentions a DDT, but I'm not sure what that is. Working on fuel injection is all new to me.

[Davidlake]

DDT is a magic box (Digital Diagnostic Tester) that plugs into a electrical connx. on the motor. You can fire injectors to test, test coils and a number of other sensor/part parameters.
Rhinda sells one that is reasonable cost.
Be sure to purchase the correct cable for your motor.
I purchased one to diagnose issues with my mercury motors. It paid for itself the first time I used it.
You can also purchase a spark gap tester and turn over the motor with it connected to the plug wires and visually check spark.
The DDT is really the way to go though.
It also reads engine hour history at different RPM ranges which is pretty cool.
The coil misfire issue can be intermittent so it can be a bit hard to diagnose w/o DDT.
The coil misfire, I my experience just gets worse and more often over time.

[PanRonnie]

Fresh plugs and a phone bore scope camera is a cheap investment
Checking plugs and piston tops might direkt you to a particular cylinder

[80Grady]

I was told this engine doesn't store any info and no way to tell hrs. Has new plugs. I have a scope and can inspect to see if theres a noticeable difference in any cylinder.