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Rigging a Verado 350 sci

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Old 08-22-2010, 12:57 PM
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Default Rigging a Verado 350 sci

Hi!

I hope you are well.

I will buy a Verado 350 sci to replace my twin Mercury 2,5 EFI SS engines (2002 model 280 hp each). I had these engines since 2006. From 1999 I ran a Promax 300 (approx 290 hp), not the X version.

When I used the PM 300 I used a hydraulic jackplate from CMC with 5,5 inch setback plus a 2 inch spacer - in total 7,5 inch setback. The weight of the PM 300 was approx. 510 lbs incl hydraulic steering. It ran well balanced with setup. I did 10 inch setback once. The boat was faster, but I preferred the balance I got with the 7,5 inch setback. Especially in high seas. The weight of the two Merc 2,5 EFI SS engines incl. Latham steeing & tiebar + pumps, extra battery, etc - are approx. 950 lbs. Despite the extra weight, the boat runs fine in high seas. The engines are mounted direct to the transom. I have tried to add 2 inch setback, but then the water entered the splashwell.

The weight of the 350 sci is 677 incl the hydraulic steering. Thats 167 lbs more than the PM 300. I need a hydraulic jackplate to get max out of the engine, so the question is then how much setback and which jackplate to buy. Bobs Machine deliver 4 inch setback in their extreme series, Detwiler 6 inches, CMC 5,5 inches with their SS offshore version, etc

My idea is to go for the 4 inch setback, and and add 1-2 inch spacers if needed. Thats 3,5 inches setback less that with the PM 300. I am not sure how much less leverage this means. When I ran the PM 300 with 7,5 inch setback the clearance from the water to the drain hulls of the splashwell was approx. 3 inches. With the 2 Merc 2,5 EFI SS engines, the water runs through.

I plan to run the propshaft approx 2-2,5 inch below the bottom at wot. Estimated top speed 80-82 mph. The boat is a Phantom 25. Dry weight without engines are 750 kilos / 1,650 lbs. Then you have to add fuel, enigne, driver, etc.

All ideas are much appreciated.

Cheeers, Toffen, Lillesand, Norway
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Old 08-22-2010, 01:04 PM
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have you looked at the stainless marine jackplate and heads up indicators.
Also did you ever find out more on the NXT type gearcase for them?
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Old 08-22-2010, 01:11 PM
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Hi!

Thanks I use two heads up when running my current set up, so I will convert this to one. I will check the stainless jackplate. I received info from two seperate dealers in Norway and Sweden that a generation 3 lower unit will come in 2011. And it will look much like the NTX drive. Thats exciting. Using a 300 lower unit does not make sense as it will go to pieces quickly due to the 350 sci torque.

Cheeers, Toffen
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Old 08-24-2010, 05:26 PM
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Hi again,

The Verado 350 sci is delivered with electro-hydraulic power steering. I am used to full hydraulic steering ala Latham (using this on my twin set up).

Is there any downfall with the electro-hydraulic power steering put up against a hydraulic steering from fx. Latham, SeaStar, etc?

The first which comes to mind is ease vs feeling what is really going on with the boat.

I am not sure if its possible to use a SeaStar helm directly on the built in steering sylinder on the 350 sci, but I will check out to be sure.

Cheeers and thanks, Toffen
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Old 08-24-2010, 06:05 PM
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Toffen, What speed did you get with 2.5 & 300 PM ? Are your shafts 20" or 25" ? "HIGH LIFE"
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Old 08-24-2010, 06:40 PM
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Hi!

I got 76-77 mph with the PM 300 spinning a Tempest 25 at 6,200 rpms - 1:1,75 gears. I get 87-88 mph with the two 280 engines spinning a Hydromotive Q-OB 25 at 7,400 rpms. However, in a hot summer day my top speed is 86 mph turning 7,300 rpms.

I expect to get 80 mph + out of the 350 sci, despite the big lower unit. As the PM 300 was "weak" in power, the 350 sci is strong (typical 370 hp).

The shaft with the PM 300 was 20 inches. The shafts with the 2,5 EFI are 15 inch, name SS. Mounted directly on to the transom, 19 inches senter line. With the PM 300 I used a CMC powerlift.

Cheeers, ToffenG

Last edited by Toffen; 08-24-2010 at 06:42 PM.
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Old 08-24-2010, 07:31 PM
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Hi Toffen,

What's up.

I have two brand new Stainless Lift's in boxes at my office... Also new a new indicator with wires...

It's for my Arrow o/b project that will work just fine with the new 350SCi You will see 75mph with a single 350 on a Arrow 28.....

Let me know...

Mange
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Old 08-24-2010, 07:46 PM
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Hi!

Thanks for message Mange My idea of a new boat ends up with a new engine and a new annex to our house. Its a diplomatic twist within the family.

I just learned that the 350 sci has a center of gravity approx. 2 inches more aft than a PM 300 / 300 XS. So I have to take that into consideration when deciding the setback. The 350 sci is approx. 60 kilos heavier than a 300xs, but much lighter than a twin 2,5 EFI setup (incl. steering sylinders and tiebar + pumps, cash tanks, batteries, etc). However, I need to keep the setback to minium, so how much are your jackplates setback?

How heavy is your outboard Arrow without engine?

Cheeers and thanks! Toffen
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