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Post by barryturano on Jul 11, 2020 19:42:14 GMT -5
2005 Sailfish 2660 with twin Yamaha F250's. I am turning 3 blade 14.625 X23 prop. Here is what I am getting WOT 5200 RPM's 49 mph 4 people and 150 gallons of fuel. Need to run with the motor tucked all the way in and almost full tabs. When she is trimmed up on a plane the top of the screw cap for the tab zinc is at the surface. Which makes my cavitation plate about 4 inches under the water. I am attaching a picture of the lower unit and the mounting holes where the motor is on the transom. It appears that I can lift my motor 2 holes. Will that help with stern lift because it runs bow high. I was going to move to a 4 blade prop. But I don't think that will solve the problem until I lift the motors. Any opinions. Attachment DeletedAttachment Deleted
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Post by abouttime2fish on Jul 12, 2020 6:01:47 GMT -5
Not many of your setups Barry, but I’d say raise them up. Bet you will be able to trim for more RPM at wot with them raised too. I’ve not heard of the 2660 having ventilation problems but the 2360 sure can, which often leads owners to lower the motors all the way down. That may have happened in your case. I’ve solved the ventilation through very aggressive use of trim tabs. It’s a stern lift issue.... which is why I think you will see it once you raise the motors. As the bow comes up, the props are in the hole in the water left by the boat. My best advice is to go read the lenco auto glide manual about how it is manipulating the tabs and then try and mimic that in your tab use.
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Post by fishnfool on Jul 12, 2020 7:21:17 GMT -5
Your motors are in the 2nd lowest position which is where SF has them mounted out of the factory. It's a compromise height to provide decent performance and to mitigate ventilation. It's the better spot for 3 blade props.
Not sure why you'd have to run with your motors tucked with tab? Porposing?
If you're going with 4 blades I'd def raise them. One hole may be enough, but with 4 blades you might be able to raise to the top hole. More ventilation will likely be the cost.
Jack plates would make the trial and effort a lot easier and they would push your props back into cleaner water.
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Post by barryturano on Jul 12, 2020 9:42:39 GMT -5
Your motors are in the 2nd lowest position which is where SF has them mounted out of the factory. It's a compromise height to provide decent performance and to mitigate ventilation. It's the better spot for 3 blade props. Not sure why you'd have to run with your motors tucked with tab? Porposing? If you're going with 4 blades I'd def raise them. One hole may be enough, but with 4 blades you might be able to raise to the top hole. More ventilation will likely be the cost. Jack plates would make the trial and effort a lot easier and they would push your props back into cleaner water. Trying to keep the bow down and on plane. She falls off plane at about 25 mph. Also getting 1.4 mpg so performance is terrible. Going to raise the motors and see what happens. Hoping that will end the problem, before having to change wheels.
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Post by fishnfool on Jul 12, 2020 14:32:47 GMT -5
Seems your over propped
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Post by barryturano on Jul 12, 2020 15:19:51 GMT -5
Agree but I am dragging the lower units through the water because of how deep they are set. First ting will be to raise the motors as I was told by Ken at Propgods and Marcus at Powertech.
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Post by jski59 on Jul 12, 2020 21:39:21 GMT -5
While your raising the motors I would definitely slide in a pair of wedges...they will definitely help in getting the bow down.
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Post by reelkul on Jul 13, 2020 18:07:19 GMT -5
On my 2660 with twin F250s I played with the motor position when I had the 3-blade props. I would still get cavitation. At the position that you have in the picture above, and one more higher the boat seemed to work the best. Whn I got my 4 blade props, I kept it at the third hole from top. Boat runs great and good mpg.
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