No more Braapp?????

[SJet]

Okay, my friend has a sn super jet. 61x cases, 61x cyl (701), west coast head (162 psi in both), speedworks dry pipe, and stock ignition.

We were just out riding, when all of a sudden (no more power). Seemed like an ignition problem? Maybe running on 1 cyl? When we run it on the trailer, it seems to be missfiring, before it hits the rev. limiter?

Here is a list of what we changed.

New plugs - No fix
Good cdi - No fix
Good coil - No fix
Good stator - No fix

Good carb - No fix
Water box looked okay, nothing loose inside?

Thanks
This boat is really got us stumped? Any idea's?

 

[Matt_E]

Since you got good compression, and good spark (?!), I suspect a broken reed petal.
Pull the intake manifold off and check.

 

[SJet]

Stator wasn't loose. We replaced it with another good one. The coil checked out good on the multimeter. We cut back the plug wires, but then used the old plug boots. Maybe we should try new boots? There is spark, but it seems small to me. I am guessing that is normal?

We will check the reeds, but the motor idles fine?

Thanks

 

[Matt_E]

From my experience, "small" or weak spark is normal on a stock system.

 

[surfjetlouie]

I have new wsm booth $6. FOR THE PAIR SHIPPED TO 48 STATES

 

[Big Kahuna]

pull the head, look at the pistons, see if there is a huge chunk missing on the exhaust side...............

 

[DaUpJetSkier]

i take it you checked for water in the gas?

 

[SJet]

Not the reeds, they are fine. Already checked for water in the gas. We put new plug boots on. We'll water test tomorrow.

 

[SJet]

Well, she had bad plug boots.

We are back brapping again.

 

[tor*p*do]

strangely enough i have found that my Kawi 750 eats boots.
it is easier just to replace plugs and boots every 30 - 40 hours.

 

[SJet]

Preventative maintenance does wonders. I am changing mine this winter. I am also going to rebuild the top end.

 

[Superjetjim]

Some things Yam just make very well... one of them is the stock plug caps - I'll pay the $250 for plug caps and coil unit over MSD caps and messing about anyday - seen it so many times!

 

[SJet]

Yeah, I agree. But doesn't NGK make good plug caps? I have used the nice rubber ones before. They seemed to work great!

 

[Idok]

crazy how some boats just eat plug boots....Ewok must go thru 1 a month at our break.....

I never understood how that coudl happen...vibration?