I just mounted my motor to my new boat and the anti-ventilization plate it right at 1" below the bottom of the transom. Is this worth messing with to get level? Also how much difference will I notice from going from a 9.8x11 prop to a 10x13?
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Motor mounting question
- Thread starter roltide05
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richg99
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I'd try to move it up. One inch dragging will slow things down. I have no idea what the prop change will do. Rich
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If you are willing to take the time it is probably worth a MPH. Try a jack plate and raise it a little higher than level where you can really see a benefit of going with the 13" prop. Good starting point with a jack plate would be around 1.5 - 2" above, measured with a straight edge off the bottom of the boat to the cavitation plate when the plate is parallel to the bottom (not tucked in or trimmed out). Remember though that, at this point, we know nothing about what boat or engine you are talking about. More information you put in the better the answers you are likely to recieve in here!
mtnwkr
Well-known member
Sorry to hijack your thread but I have a pertinent question.. The bottom of my boat has a keel(?) that runs all the way back with the drain plug in it. Should I consider that the bottom of the boat for measuring purposes or should I imagine a straight line as if it wasn't there and measure from there. Its about an inch and a half tall and the same wide. Thanks!
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It does nave an effect but when I measure I go from the actual bottom surface. Every boat will require a different end result, height wise, but the figures I gave will get you into the ballpark. Things to remember here are that the small engines we are talking about all have different water inlets on them and will react differently to additional height. Some are on the side of the gearcase and some are on the bottom of the cavitation plate behind the propeller. Props and their condition will also have an effect. When a height adjustment is made always check to make sure you have adequate cooling at speed before evaluating your performance gain or loss.
richg99
Well-known member
roltide....you know...I thought further about your query and my earlier response.
While, in a perfect world, your cav plate would be dead even with the bottom of the boat.....I guess I'd give it a try as is.
If you are like me, you hardly ever run the engine WOT. so, if you lost a little efficiency due to the mistaken height....it still is not a big deal.
Try it and then make your decision. regards, Rich
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mtnwrkr I'd go with the largest bottom surface area as your guide,,,,, that means that the little "keel" would not be an issue. Just my opinion...what do I know?... ha Rich
While, in a perfect world, your cav plate would be dead even with the bottom of the boat.....I guess I'd give it a try as is.
If you are like me, you hardly ever run the engine WOT. so, if you lost a little efficiency due to the mistaken height....it still is not a big deal.
Try it and then make your decision. regards, Rich
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mtnwrkr I'd go with the largest bottom surface area as your guide,,,,, that means that the little "keel" would not be an issue. Just my opinion...what do I know?... ha Rich
