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Old 30 March 2009, 13:01   #11
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Yes but as the engine is a lot more powerful it will tend to lean to one side - it may not have mattered with the older engine. Basically some engines are mounted an inch or 2 off centre to counteract the torque. This could cause it to chine walk as well.

But first sort out that prop and take those fins off!!!
Ok, Prop coming off as are the fins, JSP if you are about Easter weekend a trip from Knott End might be in order? At best we can have a laugh, at worst you can fish me out of the drink :-)
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Old 30 March 2009, 13:18   #12
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I do not think it is your fins as i have them on my mariner 150. On looking at your pics I cannot but think that it could be the position of your cavatation plate relative to the bottom of your boat, have you checked it?

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Old 30 March 2009, 13:22   #13
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fiddle with the trim tab, that should go a fair way to sorting it out.
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Old 30 March 2009, 13:23   #14
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Does the cavitation plate need to be higher or lower than the stern of the boat? if its lower can that cause this?
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Old 30 March 2009, 13:39   #15
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[QUOTE=neil.mccrirrick;288450] Does the cavitation plate need to be higher or lower than the stern of the boat? if its lower can that cause this? [/QUOTE

Neil it needs to be level with bottom of the hull so the water flows undisurbed from the hull over the plate and passed the engine. It is worht a check especially with the fins on.
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Old 30 March 2009, 13:46   #16
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Ok thanks, I'll check that too. Its likely to the weekend after next before I can get back out on the water, I'll let you know if I get the problem resolved.

Thanks all
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Old 30 March 2009, 13:49   #17
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Ok, Prop coming off as are the fins, JSP if you are about Easter weekend a trip from Knott End might be in order? At best we can have a laugh, at worst you can fish me out of the drink :-)
Sounds good to me Neil! Will PM you next week
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Old 30 March 2009, 13:52   #18
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fiddle with the trim tab, that should go a fair way to sorting it out.
Can the trim tab do this? I thought it would just affect a drift in direction?
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Old 30 March 2009, 13:57   #19
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just found this on another site

Under most conditions, the engine will be trimmed fairly close to the transom. However, once on plane, the engine can be trimmed slightly further away from the transom to obtain maximum efficiency. Experiment with trim until you obtain a comfortable ride based on the boat's load and sea conditions.

Large propellers on high horsepower engines normally create port list conditions on "V" hulls. If desired, the installation of trim tabs will correct this condition. The installation of a transom mounted transducer on the port side will also reduce port list.

I'll be fiddling with the trim tab a lot then :-) as slim tim advises
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Old 30 March 2009, 14:03   #20
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Aye the wee tab which is also an annode behind the prop he means as it looks like it has no offset to me, however I dont think thats your only problem, and it generally only improves the torque against your steering anyway but its woth kicking it round a notch or two.... its impossible to tell, but there might me some mis alignment in your engine that the fins are exacerbating, take them off as others have said, get that horrible prop off and go from there
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