Ran the Silverwing for the first time today

[baja1000]

First run the boat ran low 80s 6000 rpm with 28 mer clevs lifted the motors 1/2 inch and ran low 90s 7000 max rpms went back to lift them somemore and was asked to slow down or leave the lake by the cops they said it was getting to busy.So how much higher can I go

[baja1000]

Can the motor being too deep keep the RPMs down or can it be a fuel presure problem.96 260s all diomond maine fuel set up with lavorsi elec fuel presure gauges reads 30psi at ideal on both motors.I would think with 28 props rpms shoudnt be a problem

[baja1000]

any one

[fasteddie]

Motor being too deep could keep RPM down. Watch you water PSI as you take the motor higher. I try to keep around 12 to 15 PSI of water pressure at WOT. Fuel PSI sounds a bit low to me. I was told to try and keep around 38 to 40

[baja1000]

How can I turn the fuel presure up or do you think its the gauges being its all new and elec gauges are not that accurate

[RBT]

If you are using a Livorsi electric gauge they are......... Get a mechanical gauge!.,

[Kurt Graf]

Livorsi electric fuel pressure gauges are a joke. Many gauges read low. Mine did.

[pyro]

Motor being too deep could keep RPM down.

motor(S)
It had twins on it when he posted photos on another thread.


http://i29.tinypic.com/sllj7m.jpg

[baja1000]

I going to put a mechanical on it back at the motor to ck the right presure.If they read 39psi and the elecs read 30psi at least I have an Idea of whats going on.With both reading 30psi I think its the gauges.The first run in the boat you could fill the motor draging in the water when you let off the gas it slowed real hard and road like a old flat bottom in the back.I ganed 1000 rpm by lifting them a 1/2 inch what kind of window of movement can you go 1 2 3 inchs or what?

[Matt Gent]

Post a picture of the engines from behind the boat. Also try searching here for some of the Liberator pictures. If the engines are in the tunnels they can be run really high (many inches above the bottom of the sponsons), but at some point you'll need a hull-mounted water pickup.

[pyro]

Sorry for coming back and nitpicking at this thread. :rolleyes:

[QUOTE=Matt Gent;1360071] If the engines are in the tunnels...QUOTE]

Yes, they are in the tunnel.
The Silverwing is a true tunnel with no center pod. It has a bottom like an F1 boat. John Marles (us1) also owns a twin-engine Silverwing, one of only a handful made. I recall him making some comments about how it's not a forgiving boat, and demands some major respect, or something to that effect. John's boat has a pair of custom-built 2.5's that produce 340 hp each.

It's always wise to raise propshaft height in very small increments, no more than 1/2" at a time. You'll probably end up raising them till you start to lose water pressure, then dropping back a bit. The motors will never be fed flat water, they'll be cutting raw or choppy surface, so keep a close eye on temps and water pressure.

Have you spoken with John about your setep? Playing around with something this fast and dangerous on a trial-and-error basis without some first-hand help is insane. You can't afford to err...

[baja1000]

John told me 3' above outside pads thats were I started.I have a 2x6' step in the back of my boat thats not on Johns.Im already 1/2 inch hire should I go 1/2 more.

[pyro]

Once you reach a certain point, RPM's will become higher without significant speed increase. In other words, slip will he higher if the motors are too high. Also, watch for loss of water pressure. Along with handling, those are your two limiting factors when it comes to height.

[fyremanbil]

Baja, be careful with that boat. There is a real blow-over hazard with them at high speed.
You'll notice a difference in just a 1/4" change in engine height. If your too high, the back may start to feel loose. Trim angle and overall balance are important factors for tunnels, and has everything to do with how it will handle.

[baja1000]

Even if the motors are still to deep dont you think I should spin these 28 like crazy.Thanks for every ones help!!!!!!!

[pyro]

It may be easier to blow it over with the motors too deep than too high. The reduced stern lift effect causes the tunnel to compress too much air (which the step already contributes to...) and more bowlift response to trim. Watch your ass...

[us1]

Mine doesn't have the step so the setup will differ. I would raise it a 1/2 at a time until the back end comes loose. Mine will come loose long before I loose water pressure because it's a full tunnel getting clean water to the lower units. The motors will not spin up if too deep because of the clean water. Also, the Silverwings do stop fast with the hydrodynamic drag of twins, again because of the clean water.

[baja1000]

thanks John