searay/250hp diesel

[Beamishken]

I have recently installed a mercruiser 250hpD-tronic/bravo2 21"prop into a searay 200 (20'cuddy) on the first run out the boat only managed 38mph which seems a little low the engine sounds ok & seams to rev out ok but rev counter malfunction made it hard to tell .has anyone any experience with this type of rig & any advice on improving top speed

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[duncan]

bigger prop basically

in theory you should have around 45knots available if you can get it all sorted and happy I would think.

quite a heavy rig for the hull isn't it? Shouldn't matter though.

biggest issue may be getting the boat over it's resistance hump before the engine starts delivering it's power - around 7knots. At least you should be able to slip the BII a bit and get the revs rising.

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[ArthurWood]

As Duncan says, sounds a bit of a heavy motor for a 20ft boat. Try fitting a Doel fin or similar to the anti-cav plate. That should help you get on plane quicker.

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[andrewa]

Thats not bad going Ken, how did you fit such a large motor into a Sea Ray 200? I have a Sea Ray 270 Sundancer and couldn't fit in a D-Tronic due to the engine room length. Your secret would be apreciated.

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[Beamishken]

It wasnt too dificult realy . Fuel tank is directly in front of engine so just made tank shorter fuel consumpition should be roughly half & the tank was only about 8"shorter & still holds about 30 gallons which should be good for 100 miles plus at cruising speed which is good enough for an overnighter also have to re model rear seats but boat trim isnt brilliant anyway being a 10 year old american boat

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[andrewa]

My fuel tank does stick out into the engine bay its a 100US gallon could be replaced with a smaller one if dieselised. Will investigate.

Andy

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