#1 cylinder not firing

davis11111

Cadet
Joined
Jun 22, 2009
Messages
10
My 2001 Yamaha 90TLRZ is not firing on the #1 cylinder.
I changed the spark plug and coil pack of the #2 clyinder with #1. The #2 still fired and the #1 did not, apparently the #1 one plug and coil are not bad.
also the #1 plug is wet after checking each time.
Any and all help is greatly appreciated.
Thanks,
Don :(
 

robert graham

Admiral
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Apr 16, 2009
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6,908
Re: #1 cylinder not firing

may be bad fuel pump seal/diaphragm, when they leak/go bad it can shoot gas into that #1 cylinder and flood/drown it...that's why it's wet with gas check it out and good luck!
 

ncfisherman

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Apr 21, 2009
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15
Re: #1 cylinder not firing

mine was doing the same thing I had to order a power pack for mine maybe this will help
 

robert graham

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Apr 16, 2009
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6,908
Re: #1 cylinder not firing

there was a guy a couple of weeks ago with the same motor and exact same syptoms and it really had everyone stumped and the Yamaha guys went right to the fuel pump as the problem...that's the reason #1 cylinder was wet all the time..it was just flooded with gas. a fairly easy/inexpensive fix, too!
 

davis11111

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Jun 22, 2009
Messages
10
Re: #1 cylinder not firing

Hey Mates,

I put a screwdriver in the sparkplug coilwire and grounded (with a gap) with the motor turning over and it had no fire........

The #1 plug is wet but not overly wet.

I hate to say it but I think it is the CDI.

Thanks for the inputs, keep'um coming, just maybe someone will come up with a cheaper fix.......

Don
 

robert graham

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Apr 16, 2009
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6,908
Re: #1 cylinder not firing

O.K., go to yamaha outboard forums, then to marine engine.com forum, check the june 10th entry by Jamie Keeble named "yamaha 90" and read all the ideas about his #1cylinder problem and the solution...it sounds exactly like your problem...had everbody going in circles...troubleshooting some of these modern outboards not always obvious or simple...good luck!
 

davis11111

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Jun 22, 2009
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10
Re: #1 cylinder not firing

Robert,
Jamie had fire on his bottom plug and I have no fire on my top plug......
 

rodbolt

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Sep 1, 2003
Messages
20,066
Re: #1 cylinder not firing

this system is incredibly simple and all components can be tested in less than an hour.
pulser coils for cylinders 1&3 can be tested for output voltage with a peak reading meter such as a CD-77 or a DVM with a DVA adapter, voltage should be 5v cranking loaded and 14v at 1500 RPM.
low speed charge coil voltage should be 100v loaded at cranking.
thats about it for low speed inputs.
that and make sure the yellow wires are still plugged in.
crank position sensor output voltage should be 5.5V loaded when cranking.
like I say its an incredibly simple ADI ign system.
out put voltage from the CDI should be3 about 100V cranking loaded and the secondary Kv should be about 7Kv.
does take some special tools though.
 

davis11111

Cadet
Joined
Jun 22, 2009
Messages
10
Re: #1 cylinder not firing

I am continuing to find my problem(s??) and have got a weak spark to the #1 sparkplug plus rebuilt the fuel pump.

The #1 plug is still wet and not functioning when motor is running. Could this possibly be a carburetor or a reed valve problem?????

Thanks,

Don
 

davis11111

Cadet
Joined
Jun 22, 2009
Messages
10
Re: #1 cylinder not firing

In my last reply I was still looking to find my problem and today when I pulled the aircleaner I found a oil residue in the #1 carb inlet and a brown mix in the two other carb inlets. I then checked the fuel in each carb bowl with the #1 bowl empty and others full.

I pulled the #1 carb and found the needle stuck so I rebuilt the carb.

When I fired the engine all cylinders were firing and motor was running fine.

The residue that I was finding on the #1 plug was oil not gas and oil.

Thanks to all for your inputs and if I have a future problem I'll be back.

Thanks again,

Don
 
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