Yamaha 150TXRB no spark on 1-3-5 cylinders and we're on vacation!

[joelisajer]

Hello,
Long time since I posted, but was hoping someone could help with this question. I have a loss of power but still starts and runs. Can't get above 2000 RPM. Took it back to the campsite and checked all sparkplugs. Found that coils 1-3-5 do not spark (right side). Swapped coils left to right and problem stays with the 1-3-5 cylinder bank (right side). Is there anything that would kill JUST the right bank of cylinders??

I metered out the ouput peak voltage, pulser and charge coils. Peak volts good on the only on left side(130volts). Charge coil tested within specs. Pulser coil I got .5 and .4 respectively per coil (manual calls for 2.0 or 3.0 cranking) - I don't understand the "load" versus "circuit" options though.

I can understand that I may need a pulser coil, but why only cylinders 1-3-5 that failed?? The pulser reads 330 ohms per circuit and not shorted to ground, seemingly the same for both coils. Position sensor also reads 210 ohms.

Any suggestions would be appreciated,

Thanks!

[rodbolt17]

ok
1 bank missing.
on a carbed 150txrb the ign system uses a high and low speed charge coil. lose a charge coil and lose all 6.
there are two pulser coils 1 for cyls 1&4 the other for cyls 3&6.
spark on 2&5 is based on crank position sensor.

that leaves only about the CDI that could take out a bank.

now the DX,VX andSX150TXRB uses a totally different setup. they use 6 pulser coils and the charge coils are bank to bank rather high or low speeds.

unloaded simply means the device is unplugged.
loaded means its plugged in in its normal running configuration.

see why complete model numbers can be helpful?

[joelisajer]

Thanks Rodbolt,
I was hoping against that. Tried it yesterday after cleaning all connections and grounds. No change. Except occasionally the other side would kick in intermittently. Is there any type of rpm reduction safety that can take out 3 cylinders?

Guess we'll be fishing from the shore...

[joelisajer]

I believe mine is the S150TXRB

[rodbolt17]

nothing on that motor that will cut out one bank.
how are you testing spark?

[joelisajer]

Rodbolt,
Initially I tested it by removing each plug and grounding to the block. When the right side didn't fire, I rigged a primitive gap test by using a paperclip from each coil/lead and checking for at least a 1/2 inch jump. Left side got great results averaging 1/2+ spark jump. Right side got nothing at all. Then I swapped coils left to right, retested and problem remained on the right side.

After that I proceeded to check the peak output volktage and the charge and pulser coils iaw the manual specs. Only thing that didn't make sense was that the pulser coils (only two on this engine) read exactly the same resistance and voltage, but only got .5 volts when the manual calls for 3 or 4 if I recall correctly. So the last item on the troubleshooting by "default" is the cdi.

Any way to check the cdi directly?

Thanks for entertaining my questions!

[rodbolt17]

no test for the CDI itself.
however that's why they give loaded and unloaded specs.

[joelisajer]

No spark 1-3-5

Rodbolt,
Thanks for your input. I've been on work travel for the past month plus, so just getting around to changing out the cdi. Still same issue. Is there anything I'm missing here that can cause no spark on just one side? I rechecked everything to confirm and noticed that I get a momentary spark on 1-3-5 just once during cranking. Like it works but does not continue. Summers almost over here in NJ and I'm getting desperate. I just ordered the pulser coil realizing that it is not likely but don't know what else to check. I also swapped out the crank position sensor from a friend with no change.

Any ideas on what can cause this? Ever seen this type of problem before. Someone must have experienced this.....

Any help or direction, ideas are welcome. Next available appointment I can get from my marine mech friend is mid September. He has had me try some things but no success.

Looked at new boats today:-(

Joe

[rodbolt17]

are you positive its a S150 or is it an SX150?
HUGE difference.
totally different ign system and fuel system.

[madharchod]

you said you tried swapping the coils from left to right and still the same problem so when you replaced the coils back again you had spark in the left one but intermittent on right side correct
no that tells a story

[rodbolt17]

pay no attenition to the old fool behind the curtain.

[joelisajer]

are you positive its a S150 or is it an SX150?
HUGE difference.
totally different ign system and fuel system.

Hi Rodbolt ,
It may not be a S series, because the data plate only says 150TXRB, but it is definitely carbureted and not fuel injected engine as I understand the SX is. I am using the 150TXRB manuals for specs. I could never understand why my serial number doesn't coincide with the series listings though., so I may have something wrong. I attached pix to dispel any ambiguity though.

If you look at the pix of the pulser coil plug you'll notice I only have 4 wires, W/R, W/G, W/Y, AND W/Br. I also swapped the red and green coil with the brown and yellow (depinned them) then got nothing at all on either side. Swapped back to normal and got 2-4-6 spark and nothing except intial momentary spark on 1-3-5. Basically nothing at all. Actually swapped the harness from the cdi to the ignition coils left to right and problem follows. At least it's consistent in that one side of the cdi ignition harness does not produce spark, even after a cdi change!

Any other ideas?

Many thanks,
Joe

[ausnoelm]

pay no attenition to the old fool behind the curtain.

I really have no idea what that means, but I got a belly laugh out of it......

[joelisajer]

you said you tried swapping the coils from left to right and still the same problem so when you replaced the coils back again you had spark in the left one but intermittent on right side correct
no that tells a story

MADHARCHOD - Not sure what sorry that tells.... Pretty much don't get any spark on the right bank (1-3-5) except yesterday I noticed a single momentary spark when cranking initiates. Not always, but never more than just ONE. the problem started after an alarm (I presume overheat - shut down let it cool then all was well for a while and never came back once ) by a gradual degrade when it failed. It would miss occasionally, then more frequently, then mostly, then complete non fire on 1-3-5. All this within a few hours.

[joelisajer]

Txrb 150 no spark cylinders 1-3-5

are you positive its a S150 or is it an SX150?
HUGE difference.
totally different ign system and fuel system.

Rodbolt,

Today, I change or the pulser coil and yielded the same results. No spark one bank one . Though now I'm not getting spark on 2 as well. So seems just 4 & 6 are firing.

So thus far I have
1.tested all the wiring in the ignition system per the manual,
2.verified output voltage of both charge coils, pulser coils, and ignition coils and everything checks out with the proper voltage with a peak voltage meter (except I get. 4 volts on the pulser when the manual says 3-4 volts)
3.changed the cdi
4. Changed the crank position sensor
5. Just changed the pulser coil Assy - same issue
6. Disconnected all wiring to the console so the engine is stand alone, - same
7.tried with disconnecting, overheat, oil low switches - same

-I was told to check for a shifter switch- I don't have.
-was told to check tilt/trim- this has always been disconnected - doesn't work with my gauge set

Don't know what else to do at this point.. Can the stator be bad and check out good? Can the flywheel magnets go bad. Can any of these cause "no spark condition" on cylinders 1-3-5?

Any other suggestions?