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1994 Mercury 75 ignition issues

Ok! Think we finally have something that makes some sort of sense. Bit the bullet and pulled the ignition switch out the control handle and ran the continuity checks on it. Key in the run position we have no continuity from red to yellow/red or yellow/red to purple....pretty sure bad its bad in the run position. Will get a new one and report back hope new switchbox isn't fried yet :(.
 
You should only have continuity from red to purple...yel/red only hot when key is turned to start to activate solenoid and not tied in with purple at all. Engine does not use power from switch to run...
 
faztbullet said:
You should only have continuity from red to purple...yel/red only hot when key is turned to start to activate solenoid and not tied in with purple at all. Engine does not use power from switch to run...
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Unless i'm reading my service manual wrong there should be continuity to red, yel/red, pur in the run position. Its the commander switch.

Apparently i can't post picture of the continuity chart but there should definitely be continuity to the wires above in run position.
 
Nope I think you're right The guy at the boat shop confirmed the manual is wrong. This is becoming a nightmare. I picked up a switch anyway because the old one is really sticky so not a bad buy.got the shop said anytime they change a switch box they changed out the trigger on a two-stroke so his vote is probably the bad trigger making my symptoms.
 
Ok some more intel. My boat has the red stator but it only has 4 wires...looks like the new ones have a blue/white and ground. The AC voltage coming off the 2 yellow wires(charge side) at idle is a nice 14 to 18 volts. That's measured right off stator in AC. So i'm assuming charge windings are happy. The white/green and green/white wires(ignition) off the stator are measuring erratic on the meter in AC. I would think it should be good constant(roughly) AC voltage where the switchbox rectifies it and sends to coils when trigger fires. Does this point to stator being bad?

Fly wheel puller and trigger is on the way...stator is the biggy at 400 bucks.
 
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faztbullet said:
What is voltage off stator adapter?
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Blue wire? It's erratic while engine is idling...I can check
at cranking speeds in a bit. Not sure why dva is good while cranking but erratic while idling... Either something is wrong with engine or meter is wrong. I have access to a fluke... Gonna see if I can get a hold to it today.
 
Interesting side note...a friend's merc 150 with cdm type ignition... Voltage does not jump around off block... Rock solid ground while running. Ugh... No clue if what I'm seeing is normal or causing my power loss/surge issues.

At this point it's either normal or the trigger or stator. I've been thru every single ground. Even jumped the plate to ground. Hoping pulling flywheel will reveal something.
 
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If you can get the fluke use the min/max feature to see how high both the positive and negative voltage readings are in dc and what it shows in ac. I'm not an electronics wiz but if there is negative voltage in dc it will be trying to "swim upstream" on the ground cable, I would think it would have to return on the positive side and who knows what effect a.c. ripple would have. Anyway it would be helpful to know what we are fighting as to my knowledge the only two things that I can see that would have any negative voltage are the charging and ignition systems (yeah really narrows the field down right?)
 
Swagonmaster said:
I just thought of something, this sounds a lot like this recent thread: http://www.marineengine.com/boat-forum/showthread.php?466211-Still-Need-Some-Help
His problem turned out to be a defective spark plug!
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I'll try some more new plugs just in case...cheap enough to try...however the more and more i think about this issue...that wire blue off the stator adapter on the ignition side is going crazy when its idling...its gotta be the stator acting stupid when running...seems to be ok when just cranking but voltage is all over when running. I have a new sierra switch box in the boat and i'm replacing the trigger since the boat shop said they ALWAYS replace the trigger when replacing a switchbox on 2 strokes cause they have seen it too often...CDI is the only one that seems to be making a trigger. Hope it works ok with the sierra box(don't really see why it wouldn't). Might just shove a CDI stator in too just for kicks...even tho it seems like a lot of money for everything ... i guarantee you its still cheaper then bringing it in. lol
 
Yes definitely cheaper than taking it in. I would consider replacing the plugs first before spending money on anything else but that is your call, I'm not sure that the stator wouldn't be needed also.
 
Swagonmaster said:
Yes definitely cheaper than taking it in. I would consider replacing the plugs first before spending money on anything else but that is your call, I'm not sure that the stator wouldn't be needed also.
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The tech at CDI electronics said to try a plug that has a gap. My engine calls for NGK BUHW-2. He said he hates those plugs lol. He said to try bp8hs-n-10 or the v series. However, before all this the NGK BUHW-2 have worked fine for years.
 
I checked every plug ohm and continuity to ground...they seem fine. I tried an old set i had and still same dva jumping around. See the video. If i unplug all the spark plug wires and just crank the blue to ground gets about 250 volts. The video shows what its doing running at idle. It will do that at each coil as well and if i slip the leads into the stator white/green and green/white it will do that too.

https://youtu.be/o04fPAiQTuM
 
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Yes, the video was fine, I'm curious, how is the engine running now, any changes? I ask that so we don't spend time finding a problem unless it is still affecting the way the engine runs. If we are still needing to figure this thing out use the fluke meter and choose a higher range so perhaps we can see how high the voltage is actually going, the meter you were using in the video was maxing out and going off scale.
 
Swagonmaster said:
Yes, the video was fine, I'm curious, how is the engine running now, any changes? I ask that so we don't spend time finding a problem unless it is still affecting the way the engine runs. If we are still needing to figure this thing out use the fluke meter and choose a higher range so perhaps we can see how high the voltage is actually going, the meter you were using in the video was maxing out and going off scale.
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I haven't done anything to fix it since last outting. I'm trying to figure out why it didn't run good last outting...was thinking i found something with the voltage jumping around. I'll try the fluke again but the display just goes out when i try to dva the blue wire with it and i have to turn it off and back on. Maybe i'll try cranking speeds with the fluke and see if that will at least work.
 
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Popped the flywheel off(easy with the puller!) and removed stator and inspected. Looks really good...i MIGHT see a little spot on the red plastic that looks like it has turned brown a hair from heat but nothing serious. The magnets(glued in) all looked good to me. The trigger magnet ring has a line in it where to me it looks like that is just where they wrapped it around the ring and it is the 2 ends that meet. Doesn't look like a crack...not sure if anyone can confirm that "line" on the trigger magnets is normal. I replaced the trigger with a CDI trigger while i was in there. Now it seems to run even worse on the hose pipe. Timing light seems to reveal #3 firing on #1 occasionally. Getting real close to striking a match to this thing and walking away.

At this point i wish i could get my money back on the sierra switchbox...i feel like it might be bad. If i could i would buy a CDI box and stator then i'd have cdi switchbox, stator, and trigger...if that doesn't make the ignition happy...nothing will lol. Bought the sierra box at Summit racing...i know electronics are hard to get a refund on but i'll ask and see.
 
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i'm going to take the voltage regulator out of the loop at lunch and see what we get...if no better...going with cdi box and stator and will work on getting money back on sierra box. Summit racing has 100% guarantee so hopefully they honor it.
 
Sierra has the BEST warranty and will take one of their electronic parts over CDI's junk anyday. Either you DVA adapter is defective or the stator adapter is flakey
 
faztbullet said:
Sierra has the BEST warranty and will take one of their electronic parts over CDI's junk anyday. Either you DVA adapter is defective or the stator adapter is flakey
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I've heard that but the guys at cdi have been extremely helpful and their products look well made. My sierra box looks like someone sat on it and doesn't seal around the back very well. Plus I'm not seeing a number for sierra to call and talk too there techs... This box acting flakey already so it's going back and will replace with cdi. Gonna put a stator in to. I'm over all this... Time to just replace the ignition and be done. I hear the sierra box is made in Germany... You don't want German electronics. My 2 sense at least.
 
I tried taking the voltage reg out of the loop with no success. I think the stator has something going on with it.

New switchbox and stator on the way. The trigger is new. If this works out...my assessment would have to be a bad stator or adapter and none of the traditional checks worked for checking it. Glad the new stator won't need the adapter.

I'll report back after i install everything and give it a test.
 
Ran good today. Hole shot much better and not surging at high speed. Still seems to have a slight rough idle but I'm calling this thing fixed. Must have been the stator or trigger. My money is on the stator. Dva still wacky while running... Must be my meter.
 
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