1986 Mariner 90hp

[jimr]

I have a 90 hp mariner tower of power that last weekend when we were fishing I went to go from trolling to move and when I dumped the throttle it would not go over 2000 rpm and 4ish mph. I did some testing and found I lost spark on cylinders 1 3 5. I decided since this is 34 years old I would replace the stator trigger and both switch boxes. It fired up easier than ever on muffs. Now I have no spark on cylinder 2 with the new electrical hardware. I am open to suggestions. I swapped plug wires and it made no difference. I also got a used good coil from boat shop and he said he doubted that would fix my problem I think this is intermittent With timing light hooked up it sometimes flashes but not consistently.

 

[jimr]

May be fixed. I swapped the Stator back to the original and it started running on the muffs as it should. I will be taking it to the in the morning. fingers crossed

 

[jimr]

Wishful thinking on my part. still has no power under load. I am almost to the point of taking to a boat shop. I dont think I am loosing spark like it did, It starts better than it usually does. when the sun goes down some I am going to look at some more stuff. Any ideas appreciated.

 

[Mrprec09]

Hi, I a 90hp 3 cylinder 2 stroke mercury. Having no spark issue. Removed flywheel and decided to try and replace stator. My original stator 398-9710A14 the part that I bought is 398-9710a43. Is there a difference or is this just a superseded number.

 

[jimr]

After banging my head on the wall I decided to take it to a marine mechanic and he said the trigger is dead. I ordered one this afternoon, even thou I replaced everything.

 

[Faztbullet]

Still going to run like chit...triggers not bad....Do you have spark on all cylinders now?

 

[jimr]

getting pissed put a CDI trigger on it and still nothing on cylinder 2. no voltage coming from trigger on cylinder 2. I am out of ideas at this point. all other cylinders operating as they should just #2 cylinder no spark. it fires with 5 and that is firing right along no problems.

 

[Faztbullet]

Which switchboxes you purchased?

 

[jimr]

Which switchboxes you purchased?

they were off of amazon. I am only getting ~ .5 volt on dva on cyl 2 (yellow harness white wire black harness white wire is above 1 volt) as is all the others) running hooked up or unhooked

 

[jimr]

If anyone has any idea what would cause this I would appreciate knowing. Still no voltage on the #2 trigger wire but the corresponding cylinder is fine. the boat shop has been doing this a long time and he is stumped as I am

 

[jimr]

Still going to run like chit...triggers not bad....Do you have spark on all cylinders now?

still no spark on #2 any ideas?

 

[Faztbullet]

Sounds like the bias circuit is goofy in opposite switchbox

 

[jimr]

It was tested and is within range. Everything I have replaced has tested good with a meter(s)

 

[jimr]

I got a new/used flywheel hub and it made no difference still no #2 cylinder on trigger. I sent newest CDI trigger back to them so they can test it and installed original one back in boat. I will say with all the messing around with this it has never started easier than it does right now running on 5 cylinders.

 

[Faztbullet]

Ok ..basic ADI troubleshooting..
1) got spark on most cyls out of both boxes so stator is good
2) got spark on all cylinders but 1..
If cyl 5 fires but cyl 2 doesn't the SCR is not seeing polarity flip in box. If trigger wires was broken #5 wouldnt fire also. It is in the switchbox due to it being defective or the bias circuit is damaged. This is why you replace as a pair as usually the one that shows working correctly is the bad one. This damages opposite pack and when replacement is installed it doesnt fix problem as new part is now damaged

 

[jimr]

It has no signal voltage coming out of the trigger on the cyl.2 wire. cyl 5 is fine. Not hooked to the switch boxes cranking it should have 1+ volts and it has none.

 

[Faztbullet]

You have to hook to wire for #5 cly also...cannot test on one wire only. It is just a coil and 1 end is pos and other is neg then flips . If one wire is broken to trigger coil it will not have any output

 

[jimr]

FIXED Fazbullet you were correct, I got to caught up on what the guy I took it to was saying. 2 new boxes and she purrs like a kitten even with the old trigger in it.

 

[Faztbullet]

Anytime.....

 

[jimr]

Took it out today and I have had this boat 3+ years and it has never ran this good.