New Stator = dead switchbox after 10 mins running?

**gmacrae** · 11-29-2015, 09:01 PM

Hi all, just figured I'd run this by you good folk

I put a new Sierra stator in my Merc Laser 220, the boat ran fantastic for ten minutes, then died in the middle of the lake just as if it was switched off - wouldn't fire at all.

Got home, found no spark on port bank, so figured dead switchbox, swapped switchboxes to make sure problem followed it and it did.

So it seems a simple case of dead switchbox, probably pushed over the edge by a healthy new stator? The switchboxes didn't suggest any faults before swapping the stator. I have 2 new ones ordered. Just figured I should ask here in case there could be something else I should investigate or be wary of - has anyone seen a new stator kill a tired old switchbox before?

Many thanks, hope you're all well!

Gene

**tlwjkw** · 11-29-2015, 11:31 PM

did you swap stator and trigger wires also when ya made tha "box" swap? reason i ask is total loss on one side is "usually" a trigger and/or stator.. not always but more than not.....

**ChrisCarsonMarine** · 11-30-2015, 01:25 AM

As key switches are turned on and off their contacts throw off carbon and brass dust...a semiconductor.This can result in power from the battery contact bleeding into the kill wire...anything more than .3 volts applied to the kill circuit(black/yellow wires) on the switchbox can kill one or both of them.With both kill wires removed from their studs check voltage with motor off and key switch on... .3 volts or greater change the key switch.The key switch problem will be worse after a rain or other moisture situations like morning dew or melting frost.
The trigger won't kill one bank,it contains three separate windings that each trigger a cylinder on each side of the motor...in groups of 1/4,3/6,and 5/2.
Check your key switch...this is a common problem,Chris

**gmacrae** · 11-30-2015, 02:36 AM

Originally Posted by tlwjkw

did you swap stator and trigger wires also when ya made tha "box" swap? reason i ask is total loss on one side is "usually" a trigger and/or stator.. not always but more than not.....

Yep I switched ALL wires over - problem followed the dodgy switchbox, that eliminates the new stator and the ~3year old triggers correct?

**gmacrae** · 11-30-2015, 02:48 AM

Originally Posted by Chris Carson's Marine

As key switches are turned on and off their contacts throw off carbon and brass dust...a semiconductor.This can result in power from the battery contact bleeding into the kill wire...anything more than .3 volts applied to the kill circuit(black/yellow wires) on the switchbox can kill one or both of them.With both kill wires removed from their studs check voltage with motor off and key switch on... .3 volts or greater change the key switch.The key switch problem will be worse after a rain or other moisture situations like morning dew or melting frost.
The trigger won't kill one bank,it contains three separate windings that each trigger a cylinder on each side of the motor...in groups of 1/4,3/6,and 5/2.
Check your key switch...this is a common problem,Chris

Cheers Chris... The ignition key switch?? Damn I'd never think to look there, but I kinda follow what you're talking about. Will indeed check the voltage at those blk/ylw wires while disconnected. Do you think it sounds pretty weird for a new stator to apparently kill an old switchbox or it's an unlikely co-incidence?

**tlwjkw** · 11-30-2015, 05:27 AM

Originally Posted by gmacrae

Yep I switched ALL wires over - problem followed the dodgy switchbox, that eliminates the new stator and the ~3year old triggers correct?

no dva/ohm meter?
if your changin' all tha wires at tha same time doesn't eliminate anything... shows that one of, or all three things are bad.. just switch tha stator wires then ohm tha trigger... if it follows then tha switch box is probably good and ya need ta look elsewhere...........

have seen NEW stators go south in very short order too........

**gmacrae** · 11-30-2015, 03:57 PM

I'm struggling to get my head around how swapping all wires doesn't eliminate a stator or trigger fault, assuming the fault follows the switchbox to the other bank (other triggers, other supply from stator)... but i'm struggling to get my head around a lot of things at the moment!! So I will indeed double check the stator's resistances at least (dont have a DVA).

Thanks again you two, will post up results/solution when it happens

**tlwjkw** · 11-30-2015, 05:03 PM

tha only wires ya need ta swap are tha stator wires to each box... check for fire... your just swapin' tha "feed" so ta speak ta each box.. don't move any of tha coil leads from either switch box....

sounds like ya probably doin' it right but can't tell for sure!

**tlwjkw** · 11-30-2015, 06:24 PM

Originally Posted by Chris Carson's Marine

As key switches are turned on and off their contacts throw off carbon and brass dust...a semiconductor.This can result in power from the battery contact bleeding into the kill wire...anything more than .3 volts applied to the kill circuit(black/yellow wires) on the switchbox can kill one or both of them.With both kill wires removed from their studs check voltage with motor off and key switch on... .3 volts or greater change the key switch.The key switch problem will be worse after a rain or other moisture situations like morning dew or melting frost.
Chris

ok chris.. ya got me here.. how can that kill ONE switch box? there is only one kill wire (black/yellow) on tha switch? leaves there and they all are tied together at some point or another... maybe i'm missin' somethin' right in front of me?.. but i am old!

tha reason i said trigger is 'cause ya don't know who or how/what they are checkin' when ya ona keyboard.. check it all and done...........

**tlwjkw** · 11-30-2015, 06:45 PM

had a big brain fart...sorry, happens when ya get old n crotchety! leave tha trigger wires alone... jus ohm it!

**ChrisCarsonMarine** · 11-30-2015, 07:00 PM

Originally Posted by tlwjkw

ok chris.. ya got me here.. how can that kill ONE switch box? there is only one kill wire (black/yellow) on tha switch? leaves there and they all are tied together at some point or another... maybe i'm missin' somethin' right in front of me?.. but i am old!

tha reason i said trigger is 'cause ya don't know who or how/what they are checkin' when ya ona keyboard.. check it all and done...........

Not so sure why sometimes one,sometimes both...probably more like which one goes first...last year I sold 4 switchboxes to one fellow in one day...he finally told me they were going on the same motor and would last ...about 10 minutes,then fail.Wanted his money back...went to his boat and found .5 volts on the kill,changed the Pac and left the kills off and he finished his weekend choking the motor off...

**gmacrae** · 11-30-2015, 07:13 PM

Originally Posted by tlwjkw

tha only wires ya need ta swap are tha stator wires to each box... check for fire... your just swapin' tha "feed" so ta speak ta each box.. don't move any of tha coil leads from either switch box....

sounds like ya probably doin' it right but can't tell for sure!

Roger that, I had assumed the stator feeds were timed in some way so would need to stay with the same triggers and coils - gotcha!

**gmacrae** · 11-30-2015, 07:17 PM

Originally Posted by Chris Carson's Marine

Not so sure why sometimes one,sometimes both...probably more like which one goes first...last year I sold 4 switchboxes to one fellow in one day...he finally told me they were going on the same motor and would last ...about 10 minutes,then fail.Wanted his money back...went to his boat and found .5 volts on the kill,changed the Pac and left the kills off and he finished his weekend choking the motor off...

Sure does sound like similar symptoms! Can imagine if the kill voltage is right on the threshold of tripping the kill, one old switch might flip while the other might not (these boxes aren't identical to look at, think one's had a rebuild or something) - great info man thanks

**tlwjkw** · 11-30-2015, 07:33 PM

you can do like chris did with that one motor... disconnect both black/yellows from tha switch boxes makin' sure ya isolate tha wire end.. tape or whatever but you will have ta "choke" tha motor down or disconnect tha fuel ta shut it off.....

none of tha kill (black/yellow) wires have any kinda voltage on 'em.. they are tied directly ta ground then either tha ign. switch or kill switch close tha circuit when turned off and/or pulled.... when either is done ALL black/yellows are grounded.... jus pretend its an 'ole time briggs n stratten rotatory mower that ya push tha metal tab against tha plug ta kill it!.. black/yellows same as tab.

**gmacrae** · 11-30-2015, 08:49 PM

Originally Posted by tlwjkw

you can do like chris did with that one motor... disconnect both black/yellows from tha switch boxes makin' sure ya isolate tha wire end.. tape or whatever but you will have ta "choke" tha motor down or disconnect tha fuel ta shut it off.....

none of tha kill (black/yellow) wires have any kinda voltage on 'em.. they are tied directly ta ground then either tha ign. switch or kill switch close tha circuit when turned off and/or pulled.... when either is done ALL black/yellows are grounded.... jus pretend its an 'ole time briggs n stratten rotatory mower that ya push tha metal tab against tha plug ta kill it!.. black/yellows same as tab.

Aha! I'm with ya now!