1991 Mercury 135 V6 only firing on 3 and 5.

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Looks ta be MORE than enough for tha alarm..............

It's the top trigger wires, tucked in tight so the advance doesn't have a prayer.

John

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Bryan, get us some pictures so we can give you a battle plan.

For sure it starts with matching some parts, cleaning up some wiring, and then taking some readings. This is a good time of the year for that. Parts on eBay tend to go pretty reasonable.

We convert these things back and forth all the time. I think my XR4 has been a 16 amp 3 times and a 40 amp 4 times. Parts have to match or no fire or too much fire as in smoke. (Not bad electrics, I've been playing.)

Lead dress on the trigger harness is critical to allow it to advance with the throttle. That's why we got baffled on the wires coming in from the right.

hope it helps
John

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Sorry about the wait guys, I have to watch my 2yo daughter on weekends
while my wife works. Here are some pics of the flywheel, it was too late
for me to get pics of the starboard. I'll try in the morning when my wife gets
home. Unfortunately the boat is parked at my moms so I can't get pics quickly

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[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Well, at least the stator and flywheel match. That's a 16 amp flywheel. I have one in my lap as I type. Only difference is mine is red.

It originally had the 40 amp wet-back regulator in it. The empty screw holes on the back of the engine are for the related terminal strip. It's been converted to 16 amp, which is OK unless you have a ton of electronics and need the 40 amps.

A common screw up is this: If he used the original stator mounting screws, they are too long and will interfere with and probably damage the leads from the trigger. A damaged trigger can take out switchboxes.

The stock screws for 16 amp are 1-1/16" long. 1" will work. I think the 40 amp are 1-1/4" or 1-5/16"

Lead dress for the harness coming from the trigger is critical. It should be on top of everything else coming down the side of the engine, and be held only by one zip tie through the hole on the left side of the switchbox mounting plate. It must be free to go through the entire range as driven by the throttle lever without interfering with the flywheel or anything else.

hope it helps
John

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Thanks for the help John, Bhile, SSchefer, and Dukedog. I'll pickup a factory
manual and a dva and go from there. Hopefully all the electronics aren't shot.
This project will probably have to be put off, as I have to finish up my resto
on my 16' sylvan. Thanks again guys, I'll probably post more questions on this
motor when I begin rewiring it. I had hoped it was going to be something
really minor.

P.S. Which manual would be better a pre 1989 that covers a 16 amp system
or a 1989-newer that covers 40 amp systems? I'm not sure what other
changes were made on this motor over the years.

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Thanks for the help John, Bhile, SSchefer, and Dukedog. I'll pickup a factory
manual and a dva and go from there. Hopefully all the electronics aren't shot.
This project will probably have to be put off, as I have to finish up my resto
on my 16' sylvan. Thanks again guys, I'll probably post more questions on this
motor when I begin rewiring it. I had hoped it was going to be something
really minor.

P.S. Which manual would be better a pre 1989 that covers a 16 amp system
or a 1989-newer that covers 40 amp systems? I'm not sure what other
changes were made on this motor over the years.

I use a combination of the Mercury Manual, and a PDF manual I got on eBay for about 10 bucks with a wide range of information. The factory manual will probably cover both systems. Basically they went from 16 amp to the 40 amp single coil wet regulator system, to a 40 amp dual coil, dual regulator system. The basic engine is close enough otherwise for maintenance purposes.

If it were mine, I'd do an ohmmeter check of the stator and trigger. Go ahead and unhook everything and leave it hang for now. It's routed wrong anyhow, and the wiring is clear and straightforward in the manual. If they ohm out OK, watch eBay for switchboxes and buy a pair cheap. If the stator or trigger is bad, look for those also. The triggers are all the same for V6's, and any 16 amp stator should work fine.

Likely the advance module has been destroyed. Discard it and re time the engine. We can help you with that.

If you wish to go to a 40 amp system, you can mount 2 regulators where the advance module was. (been there, done that.) If you plan to do that, you need a 40 amp dual reg stator, and a 40 amp flywheel. If the hack changed the flywheel cover, you'll need one of those also. The rest can be spliced and taped. The connectors are a weak point anyway.

hope it helps
John

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Thanks John, I'll probably stay with a 16amp stator since they're cheaper than
the 40's and I already have the flywheel.

 

[sschefer]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Need some pictures. Sounds like you may have a "sschefer" motor. All production motors went to 40 amp systems in '89/'90. So its been changed or tha whole powerhead may have been changed. PICTURES!!!!!!

Not true. The 40 was an option up to the EFI motors but most of the 135/150 motors were sold as fishing motors and they sold better with the 40's so they could charge batteries better. That was when most trolling motors were 12v and not 24 and 36 like today.

The 135/150 can be a little dull on the hole shots and sticking with the 16 will help with that. The 40amp stator is really two 20 amp stators and requires dual voltage rectifiers/regulators. Even pieceing one together on ebay can run you nearly as much as an aftermarket mini alternator kit that can be had with up to 90amps of output.

Stick with the 16, you'll be just fine.

 

[Dukedog]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Gonna differ with ya on tha "option" part. Never was an option on any of tha motors. Last year for tha 16 was '88 Tha water cooled 40 REPLACED it on all 135,150,175,and 200 in '89. Tha water cooled regulator and stator had one stator and one reg/rectifier. Went away cause of heat issue. Couldn't keep it cool enough and caused problems even when they put tha water tube between tha top of tha motor down to tha poppet ta try ta elliminate air pockets in tha divider. Tha 40 amp system came about for all tha electrics, electronics and efi's being used and had nothin' ta do with tha trollin' motor stuff.

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Checked the trigger, stator and switch boxes with the ohm meter.
trigger disconnected
ohms
brown(yellow sleeve) to purple(black sleeve) =1152
purple(" ") to white(" ")= 1145
white(" ") to brown(" ") = 1145

All in spec according to my chart.

stator wires disconnected
stator yellow to yellow .5 ohms, my meter only reads to tenths on the
200 scale so I don't know if this is in spec or not. specs say .25-.45ohms
continuity is questionable, the numbers would just bounce around and only
if the probes were placed just right. They never read back down to 0.
This was checking each yellow to black stator wires, could not get reading
from yellow to engine ground.

swith box bias circuit check
with white/black jumper disconnected white/black pole to ground =1269 ohms
on both, with newer cdi switch box removed the old box read 1402 ohms,
I didn't check the cdi box by itself because I was freezing this morning.
All readings taken at about 32 degrees this am, unsure how much temp
effects readings.

so does this mean the stators shot?

 

[Dukedog]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Here is your "ohm" test for tha 398-5454a34 stator...........

Blue ta Red............................4450 ta 4650
Blue/white ta red/white............same
Red ta ground.........................65 ta 75
Red/white ta ground................same
This is all you can do without a DVA. It does identify a bad stator most of tha time though. Tha DVA is a little more precise.............

Checkin' tha yellows will only tell ya 'bout tha chargin part.

Don't have much faith in any kinda switch box test other than with a DVA.

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Thanks dukedog, I printed off cdi's stator troubleshooting guide
and it tested as follows
blue to ground 3.95 on 20k setting( lowest I could get a reading)
blue/white to ground only read on 2000k setting jumped to 1600-1700
and counted down.
red to ground and red/white to ground both were 65.9ohms on 200 setting.
So it looks like the high speed coils are ok and the low speed coils are
junk. So I guess this means the stator is junk?
Are cdi stators good I see some on ebay for pretty cheap?
I guess I need to determine the cause of the stator failure
after only 3 weeks and get a set of matching switch boxes.

 

[Dukedog]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Guess they are. Lotta people use 'em. I don't use 'em mainly 'cause I really "turn tha wick up" on most of my stuff.

If you see an a35 it will work also. GL with it........................D

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Check for contact between the stator and the flywheel. If there is any, find out why.

Yellows should be isolated from ground, including the black ground wire. All the wild readings look like perhaps displaced (hit) laminations.

hope it helps
John

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

I'm going to try to find a suitable flywheel puller tomorrow and try to
pull the flywheel. Crossing my fingers hoping it doesn't need a new upper
bearing.

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

I'm going to try to find a suitable flywheel puller tomorrow and try to
pull the flywheel. Crossing my fingers hoping it doesn't need a new upper
bearing.

Have patience, grasshopper.

Don't try to pull it with anything but the puller that threads into the center hole in the flywheel. Don't remove the flex plate bolts for anything.

Upper bearing isn't that big a deal, anyway. I'm betting on stripped screws, hozed upper bearing carrier. (stator holder)

John

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Finally got my DVA, an es530, flywheel puller, manual, and strap wrench.
I checked the ignition and results are:
stator
blue- 290v
blue/white-27v
red- 27v
red/white 27v

trigger
all leads in black sleeve- 3v

switch box
SW stop circuit- 300v on both
SW bias circuit- 1.5v on both

all tests with leads connected. spark advance and lube alert disconnected.

Am I supposed to disconnect the white/black stripe wire between the switch
boxes when checking the bias circuit of each?

The stator appeared fine no signs of rubbing, no play in crankshaft, correct
1 and 1/16 stator screws, stator/ trigger holder in good shape. The top of
the stator appeared to have possibly gotten hot, will post pic.

The trigger was loosely in place(SLOP), had some signs of rubbing, and had
cracks on the top but it checked out ok with the VOM and DVA.

So should I just replace the stator after sorting out the wiring?
John what wires do I need to splice, and can I just leave the spark advance
and lube alert disconnected or is there more to it. Should I leave the voltage
regulator connected?

 

[bryanwess2000]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

stator pics

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What would cause this?

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

Finally got my DVA, an es530, flywheel puller, manual, and strap wrench.
I checked the ignition and results are:
stator
blue- 290v
blue/white-27v
red- 27v
red/white 27v

The Blue/white should be about the same as the blue. That would take out one switchbox. Makes me wonder if you have crossed wiring to the trigger or coils in addition to all the other faults. Try it again disconnected to isolate whether the stator or the switchbox is at fault. If the stator tests correctly in both ohms and voltage when disconnected, then the switchbox is at fault.

trigger
all leads in black sleeve- 3v

switch box
SW stop circuit- 300v on both
SW bias circuit- 1.5v on both

I assume you didn't test the yellow sleeve because you couldn't get to it.
Peak on the trigger about double bias looks good. You should disconnect the jumper and test on each switchbox.

all tests with leads connected. spark advance and lube alert disconnected.

Am I supposed to disconnect the white/black stripe wire between the switch
boxes when checking the bias circuit of each?

Yes

The stator appeared fine no signs of rubbing, no play in crankshaft, correct
1 and 1/16 stator screws, stator/ trigger holder in good shape. The top of
the stator appeared to have possibly gotten hot, will post pic.

Finish the testing, it's probably bad.

The trigger was loosely in place(SLOP), had some signs of rubbing, and had
cracks on the top but it checked out ok with the VOM and DVA.

It just lays under the stator with plenty of freedom. It is moved by the throttle linkage for timing. If the wires are frayed or the sleeving damage where they come out sternward from under the stator, replace it. That's where they usually fail. Also, with all 6 stator leads disconnected, test between each wire in one sleeve and ground with the ohmmeter on a high range while pressing downward and rotating the trigger. You're looking for a ground fault that will reliably take one cylinder out of a switchbox.

So should I just replace the stator after sorting out the wiring?

Be sure the rectifier is good. Theoretically a short there shouldn't hurt, but it might overheat the stator.

Perhaps the hack mechanic spun a 40 amp flywheel over the stator for a short time, weakening it.

John what wires do I need to splice, and can I just leave the spark advance
and lube alert disconnected or is there more to it. Should I leave the voltage
regulator connected?

You only have to splice wires if you're putting in a later pulse technology regulator. Then it would be obvious, as the color codes are about the same. The connectors are different.

If you don't have oil injection on it, remove and discard the lube alert. Leave the temp switch and the wire to the cannon plug harness under a screw on the terminal strip mounted above the switchboxes.

You may discard the advance module. Set your WOT timing at 23 degrees BTDC. You're hunting a gremlin, so it helps to discard gremlin houses.

If there's any obvious damage to the voltage regulator or it's harness, discard it. If you wish you could hook it up later, and see if it is effective. It shouldn't even have any effect unless the battery is fully charged. If you discard it, your battery will need reasonable periodic maintenance.

hope it helps
John

 

[j_martin]

Re: 1991 Mercury 135 V6 only firing on 3 and 5.

What would cause this?

Something was wrong. Miswired to switchboxes, shorted lead, shorted rectifier, shorted regulator, wrong flywheel, or a single turn short in the stator itself.

hope it helps
John