Yamaha 130 has random miss at idle

HcK

Seaman Apprentice
Joined
Aug 27, 2021
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43
Crack open a cold one and look at this carefully.-----Something is wrong with #2 and #3 wiring.----Checked fuel pump diaphragm ?
Wiring doesn't just change, and the wiring would come from the CDI and both CDI boxes function other motor fine. . .timer base tests fine, stator tests fine. . .fuel pumps been replaced.
 

HcK

Seaman Apprentice
Joined
Aug 27, 2021
Messages
43
Crack open a cold one and look at this carefully.-----Something is wrong with #2 and #3 wiring.----Checked fuel pump diaphragm ?
How can you make a comment pointing to the wiring on #2 and #3,implying it has a problem and then the next line point to the fuel pump? Makes me question the ranking method on this platform.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,784
Sorry----It is up to you to do the trouble shooting on your motor.------So many folks do not understand the concept of a 2 stoke.----You need spark at the right time.-----Correct amount of fuel.-----Compression in the cylinders.------And compression in each of the 4 separate crankcases.------Your motor issues should be easy to figure out.-----But I will step aside on this one that is for sure !----
 

HcK

Seaman Apprentice
Joined
Aug 27, 2021
Messages
43
Sorry----It is up to you to do the trouble shooting on your motor.------So many folks do not understand the concept of a 2 stoke.----You need spark at the right time.-----Correct amount of fuel.-----Compression in the cylinders.------And compression in each of the 4 separate crankcases.------Your motor issues should be easy to figure out.-----But I will step aside on this one that is for sure !----
You have done nothing but throw out randomness, and try to be funny. The only wiring from the CDI is 1 wire to each coil, its numbered and has always gone the same place. So when you say its the wiring to #2 and #3 it seems as tho you don't know the set up of the motor, because if the CDI works fine on the other motor it would not be the wiring and none of the wiring going into the CDI would be independent to either #2 or #3. I have no problem doing trouble shooting and have, yet everything so far has pretty well come back in specs, or tested good.
 

99yam40

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Sep 7, 2008
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9,077
if the wires in the harness were to short across 2 & 3 or be crossed somehow, you would see it with the timing light lighting up the wrong TDC area if you paid attention
 

HcK

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Aug 27, 2021
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43
if the wires in the harness were to short across 2 & 3 or be crossed somehow, you would see it with the timing light lighting up the wrong TDC area if you paid attention
Its the proper cyl. You can actually see the cyl # each tine it lights up. And 2 has the full scale like I said, and 3 just shows TDC. 4 jist shows TDC
 

99yam40

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Sep 7, 2008
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9,077
well if you have good compression ,spark at correct time, and the carbs work well on the other motor, only thing I can think of is bad seal between crankcases on the crankshaft.

I believe 2 and 3 are next to each other on the crank
 

HcK

Seaman Apprentice
Joined
Aug 27, 2021
Messages
43
well if you have good compression ,spark at correct time, and the carbs work well on the other motor, only thing I can think of is bad seal between crankcases on the crankshaft.

I believe 2 and 3 are next to each other on the crank
well if you have good compression ,spark at correct time, and the carbs work well on the other motor, only thing I can think of is bad seal between crankcases on the crankshaft.

I believe 2 and 3 are next to each other on the crank
Is there a way to test this?
 

w2much

Lieutenant
Joined
Jun 22, 2005
Messages
1,285
I stumbled upon this thread this evening and of course read it because I am having a similar problem which has not been diagnosed yet. Is it possible that a small amount of water intrusion would do this ? Either through the exhaust plate or head gaskets. The final reply on this thread was unanswered I was hoping to see how it ended up. A seal in the crankcase or crankshaft journal seal would be the end of my motor. Might cost me but save a whole lot of time.
 
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