Custom/Hybrid Sv1 vibration.

[Just4Fun]

Lookin for any ideas on this before I tear down motor.

Sv1 hull
Dasa 850
TNT V2 system
Mikuni 46's
Php Mani vf3's
H20 148 pump
Brand new cold fusion mounts


I ve got a decent vibration from ski really noticeable in the water. Doesn't seem out of the norm when it's on the trailer.
So far I've
-replaced the driveshaft and impellar + installed new bearings and seals in the pump.

-aligned the engine without the dampner and its shimmed properly.

Motor turns freely but it keeps losing the mag side powervalve bolt I can only assume that is were the vibration is coming from. I just pulled the front cover and flywheel key looks good.

Any ideas before I pull my motor apart will be greatly appreciated..

 

[Fro Diesel]

Its the motor mounts.

Dont they make different durometer mounts now for this reason? Were they new or used? What color are they?

I would toss some stock or different mount on the ski before i tore down a motor.

Never heard of a motor give any warning, except when they lean out and run amazing right before they blow....
Its not a ford or subaru...

 

[Just4Fun]

Bought the mounts new off a member here, red anodizing with black rubber..

 

[Just4Fun]

I have some couch mounts out of a raider I could throw in and run just to rule it out

 

[bach6177]

The motor mount are prob starting to separate. Currently have the same problem.

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[Just4Fun]

The motor mount are prob starting to separate. Currently have the same problem.

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These mounts were brand new and maybe have one hour of use since my build, vibration has been there since the first time I put it in the water.

 

[bach6177]

Yeah that's probably not the mounts


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[erik mx45]

i see your flywheel is cut mybe its not balanced?

 

[sneds]

I fought the same issue all summer a few years ago and it ended up being a stripped motor mount (threaded insert in the hull). Worth checking... Hope you find it soon.

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[Just4Fun]

i see your flywheel is cut mybe its not balanced?

Good idea, I will give this a shot I ve got another ski I will pull one off to test..

@speedysprocket lightened the flywheel, I have two other flywheels from him and they run great no problem..

 

[Just4Fun]

I fought the same issue all summer a few years ago and it ended up being a stripped motor mount (threaded insert in the hull). Worth checking... Hope you find it soon.

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I'm gonna double check this shortly.
What kind of a hull was it?

 

[speedysprocket]

I balance all my flywheels... If you swap it and find that's the problem, I will rebalance it for you.


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[Just4Fun]

I balance all my flywheels... If you swap it and find that's the problem, I will rebalance it for you.


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Thanks, have you ever heard of a flywheel being out of balance and causing a vibration?

 

[speedysprocket]

Often times, stock flywheels aren't even balanced. They'll have material removed, but not enough or not in the right place. If I flywheels balance is off substantially, then that engine would surely vibrate more the usual.


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[jo5hi3]

switch over to regular couch mounts. I think the cold fusion mounts are stiffer.

 

[Just4Fun]

Vibration feels just like a bent prop or when you get somethin in the intake.
I recently had a motor that just shook like crazy and this is not the case, the vibration is very rpm oriented it shakes slow when idling around and faster as your rpm increases. Not sure if this makes since but it's kinda hard to describe..

 

[Kohldanielzimmer]

Do you have a leak in pump shoe to hull seal or a pump seal to pump causing significant cavitation?

 

[Just4Fun]

Do you have a leak in pump shoe to hull seal or a pump seal to pump causing significant cavitation?

Pump shoe was installed by tigercraft and the seal is tight with a dab of clear silicone.

 

[Just4Fun]

I just double checked all my mounts and bolts. Everything is tight so I swapped in a known good flywheel out of my yami powered X2 and I'm gonna go for a test this afternoon..

Thanks for all the helpful suggestions.

 

[Fro Diesel]

Please let us know the results. I would swap in a set of couch mounts before i did anything else.

Stiff mounts will exacerbate any vibration and transfer it to the ski, instead of absorbing and dampening vibration.

Its like when i put stiff motor mounts in my turbo car. Yeah it made the shifts tighter, and things handle better, but it rattled your teeth at stoplights and i sold them at a loss and went back to new OEM mounts asap.