Yamaha problem

[billbuster84]

Boat started skipping and struggling on the ride back to the hill yesterday. Changed the plugs first thing and fired it up in the hose. It is still not acting right. Pulled the new plugs and looked at each. #2 plug has gas pooled in it and no evidence of it sparking. What's the best way to verify it is the coil, or something deeper? Motor is a 2002 Yamaha 70, 2 stroke. If it's just a coil, I found some on eBay for around $25. Can't seem to find one local, especially with it being Sunday.


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[CUducks648]

Ground the plug to side of block and turn over the motor to see if you have spark.

[DRDUCK]

Compression Test

[Relentlous]

Plug wire. Fire up the motor and touch the outside of the plug boot. If it shocks you, the wire is bad

[willyworm]

Or if you don't wanna get the piss shocked out of you go buy a spark checker at the local auto parts store. Hook it up between the plug boot and the plug. If you don't see fire then you likely got a bad coil.

If you don't have spark switch the coil out with another cylinder. If the fault follows then it's the coil. If not, you got another issue.

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[willyworm]

Out of curiosity, did you gap those new plugs before installing em?

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[billbuster84]

I did gap them per the sticker on the inside of the motor housing


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[Gone South]

Crank it on the hose and pull one plug wire off at a time momentarily and see if the motor slows down. If it doesn't then you're not firing on that cyl. To verify a coil just switch 2 coils around and see if the wet plug follows the coil. Go ahead and check compression and make sure you got good gas with no water in the tank. Give an update after all that

Edit to add, I doubt it's your coil as they rarely fail but it's worth checking. Don't rule anything out

[ecu1984]

Or if you don't wanna get the piss shocked out of you go buy a spark checker at the local auto parts store. Hook it up between the plug boot and the plug. If you don't see fire then you likely got a bad coil.

If you don't have spark switch the coil out with another cylinder. If the fault follows then it's the coil. If not, you got another issue.

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this right here

[Goin Coastal]

Crank it on the hose and pull one plug wire off at a time momentarily and see if the motor slows down. If it doesn't then you're not firing on that cyl. To verify a coil just switch 2 coils around and see if the wet plug follows the coil. Go ahead and check compression and make sure you got good gas with no water in the tank. Give an update after all that

Edit to add, I doubt it's your coil as they rarely fail but it's worth checking. Don't rule anything out

Dont just switch the coil leads. This will cause timing issues. Switch the whole coil over.
Over get an ohm meter and check the coils. You can find the proper readings online. If they check out move to the power pack and check it. If good, move to the trigger then the stator.

[billbuster84]

Dont just switch the coil leads. This will cause timing issues. Switch the whole coil over.
Over get an ohm meter and check the coils. You can find the proper readings online. If they check out move to the power pack and check it. If good, move to the trigger then the stator.

When checking the coil yesterday with an ohm meter I checked from the plug wire to the wire that goes to the power pack. All three cylinders read between 9.5-10.2 kilo ohms. I'm trying to find the specs online now.


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[Duck cutter]

any updates?

[billbuster84]

Just got back in town less than an hour ago. Been out of town for a few days working. Heading out to troubleshoot some more now


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[billbuster84]

I've checked all three plugs to a ground and all three are sparking. Motor seems to be running a little better, but it's not under a load on the hose. Hopefully getting a compression tester tomorrow.


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[billbuster84]

After putting new plugs(old one in #2 fouled), I noticed that cylinder still getting too much gas. Finally got some time today to mess with it, and found the diaphragm on the emergency fuel valve, that is attached to the #2 carb, was busted. It was feeding too much fuel to that cylinder. $8 part is on its way, and I will hopefully be back on the water by Tuesday.


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[DRDUCK]

Run a compression test. Trust Me

[billbuster84]

Run a compression test. Trust Me

Ran it yesterday. Compression is fine.


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[DRDUCK]

Good deal, you should not have a problem getting it right then.

[billbuster84]

This is the diaphragm on the #2 cylinder.


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[willyworm]

That's the fuel enrichment thingy isn't it?

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