Yamaha 130 has random miss at idle

[HcK]

I have a pair of 1996 yamaha 130 saltwater series on a 1996 24ft WAC w/30in bracket. My port motor has a random miss at idle and stalls/becomes hard to start at but only sometimes when on the water. I have done/tested.
Stator
Stator DVA. High Low
Bad motor Volts 60 204
Good motor Volts 60 209
Bad motor Ω 74 744
Good motor Ω 74 745
I have pulled the CDI box off the good motor and put on bad motor and does not change. I have replaced coils with known good ones. Has new plugs, have rebuilt carbs./put carbs from good motor on and does not change. I can unplug both #2 and #3 plug wires and motor does not change in the way it runs. One video attached shows just the miss, the other shows motor running with 2 plug wire removed with no change.

 

[w2much]

Compression test results ?

 

[HcK]

Compression test results ?

#1-141 #2-134 #3-140 #4-135

Also, when we test spark on the cyls both are able to jump a 7/16 gap. . .and both plugs seem to be wet. . . which would suggest the cyls are getting spark, and fuel

 

[99yam40]

for a cylinder to fire and burn properly you need good compression, good spark at the correct time, and the proper fuel to air ratio.
use a timing light to verify spark for each cylinder it hitting when it should.

if they all are then you are left with too much fuel or not enough fuel in some cylinders

 

[HcK]

for a cylinder to fire and burn properly you need good compression, good spark at the correct time, and the proper fuel to air ratio.
use a timing light to verify spark for each cylinder it hitting when it should.

if they all are then you are left with too much fuel or not enough fuel in some cylinders

Timing at idle matches good motor, right around 3° ATDC . . .So i have good spark, good timing, good compression . . .and I can move the carbs motor to motor, other motor still runs good with bad motor carbs, and bad motor still runs bad with good carbs. . .have replaced all gaskets as well. . I ran this motor 40 miles off shore trolled all day and back, on back to back days. . with out a hick up. . . but the day before and the day after the trip it acted like this. .

 

[99yam40]

you will have to monitor spark and timing on each cylinder while the problem is there

 

[HcK]

you will have to monitor spark and timing on each cylinder while the problem is there

I guess my issue is the problem only last for a second, the motor loses around 200-300 rpm, and then jumps back up to idle. . then At some random point in tine does it again. Its not a replaceable problem to test spark or fuel during.

 

[racerone]

Motor sounds just awful in video #1 in my opinion.

 

[99yam40]

I guess my issue is the problem only last for a second, the motor loses around 200-300 rpm, and then jumps back up to idle. . then At some random point in tine does it again. Its not a replaceable problem to test spark or fuel during.

a timing light hooked to a plug wire while this happens will show if spark is a problem on that plug.
or you can keep throwing parts at it to see if you can get it to stop doing what it is doing

you need to know if you have a spark problem or not

 

[HcK]

Motor sounds just awful in video #1 in my opinion.

I'd say that's just in the recording, as the 2 motors sound the same sitting here running. Its like my phone cuts out the actual exhaust noise and picks up only mechanical sounds. When it misses and your standing here, its obvious, i recorded the video and its hard for me to tell when it does it in the recording.
To go back on a previous statement of mine, I can't actually justify that I'm getting fuel in those 2 cyl as I have the oil injection, so that could be why the plugs are wet, however that would mean 2 totally separate carbs are exhibiting the same issues, and the other 2 are not.

 

[HcK]

a timing light hooked to a plug wire while this happens will show if spark is a problem on that plug.
or you can keep throwing parts at it to see if you can get it to stop doing what it is doing

you need to know if you have a spark problem or not

The error/miss lasts as long as a sneeze. Its about as long as the gap in time from one flash of the timing light to the next. We have watched the timing with no visible change when this happens. Did that yesterday. Along with checking the timer base, which came back in Ω and DVA specs. Im not just throwing parts at the motor, but I have a good everything sitting on the other motor if I wanna test something, and the CDI is 3 bolts and a few plugs to switch over less then 5 mins. . easy test to check that off the list, did same with coils, can check that off. . .not sure why one wouldn't take these steps given the option.

 

[HcK]

Motor sounds just awful in video #1 in my opinion.

 

[racerone]

Checked the flywheel key ( timing )----Possibly the key is sheared.----Timing light may not show a sheared key.---Have you tried adjusting low speed mixture screws on carburetors ?----Lean sneezing is not well understood.------Checked the reed valves on this motor ?

 

[99yam40]

The error/miss lasts as long as a sneeze. Its about as long as the gap in time from one flash of the timing light to the next. We have watched the timing with no visible change when this happens. Did that yesterday. Along with checking the timer base, which came back in Ω and DVA specs. Im not just throwing parts at the motor, but I have a good everything sitting on the other motor if I wanna test something, and the CDI is 3 bolts and a few plugs to switch over less then 5 mins. . easy test to check that off the list, did same with coils, can check that off. . .not sure why one wouldn't take these steps given the option.

if this motor runs the same on 2 cylinders and 4 cylinders, it is not just a random miss

"I can unplug both #2 and #3 plug wires and motor does not change in the way it runs. One video attached shows just the miss, the other shows motor running with 2 plug wire removed with no change"

did you check to see if 2 and 3 are hitting steady with the light and what timing they were hitting at?
you do realize TDC should be marked on the flywheel for all cylinders, if it is not you can mark them

 

[HcK]

if this motor runs the same on 2 cylinders and 4 cylinders, it is not just a random miss

"I can unplug both #2 and #3 plug wires and motor does not change in the way it runs. One video attached shows just the miss, the other shows motor running with 2 plug wire removed with no change"

did you check to see if 2 and 3 are hitting steady with the light and what timing they were hitting at?
you do realize TDC should be marked on the flywheel for all cylinders, if it is not you can mark them

Yes, I'm aware TDC is marked on all, and #1 and #2 actually give a scale. I will go down and double check as I'm not 100% if we did or not.

 

[HcK]

Checked the flywheel key ( timing )----Possibly the key is sheared.----Timing light may not show a sheared key.---Have you tried adjusting low speed mixture screws on carburetors ?----Lean sneezing is not well understood.------Checked the reed valves on this motor ?

I can swap carbs with the other motor and it still happens, and good motor still runs good with other carbs. Key is still intact. Have inspected reeds, and they all seal.

 

[racerone]

Double check that wires FROM THE CDI module are going to the correct coils.-----When you unplug #2 and #3 wires the motor has to respond.-----Some thing is wrong with the way coils are wired / positioned !!!

 

[HcK]

Double check that wires FROM THE CDI module are going to the correct coils.-----When you unplug #2 and #3 wires the motor has to respond.-----Some thing is wrong with the way coils are wired / positioned !!!

They are good, my wires are numbered on each. Can switch the CDI boxes motor to motor. Problem stays in the same motor.

 

[HcK]

if this motor runs the same on 2 cylinders and 4 cylinders, it is not just a random miss

"I can unplug both #2 and #3 plug wires and motor does not change in the way it runs. One video attached shows just the miss, the other shows motor running with 2 plug wire removed with no change"

did you check to see if 2 and 3 are hitting steady with the light and what timing they were hitting at?
you do realize TDC should be marked on the flywheel for all cylinders, if it is not you can mark them

Ok, so it seems like #2 cyl is never firing with the timing light, but #3 reads right where it should.. . # 2 coil will jump a 1/2" gap then become intermittent if you try to make the distance any further. The #3 will jump well over 1/2". As far as timing light changing when really misses, there is an rpm drop for a second, so the pulse of the light does change, but the timing does not. Can mover coils around and this does not change. But remember I can pull either or both 2 and 3 off with. No change . . but 3 is firing when it should with the timing light. . .

Update: #2 is firing with timing light, clamp was not on properly for original test.

 

[racerone]

Crack open a cold one and look at this carefully.-----Something is wrong with #2 and #3 wiring.----Checked fuel pump diaphragm ?