lesson on twin stepp take off
#31
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From: IL
This may sound like a stubd queston but its not. first what is the make of the boat? Does the boat have a pad as well as steps? If your boat does have a pad do you have blow out vents under the pad with shut off valves in the engine compartment? Most step bottom boats that don't get on plane quick need to get the air that is trapped under the pad out. Donzi 35ZRs have blow out vents and I believe Fountain does the same. When you take off try neutral positon on your tabs that would be around 3-4 depending on your boat, make sure your drives are tucked all the way in and ease your throttles foward, If you feel the slip back off very slight on your throttles until you feel the grab and then push foward. Bravo 1 props are your best choice with 496s, Going 5 or 6 blade will not help with the slip and will destroy your X drive, 496s don't run XR drives. I have 496s in my 33 ZX I added blow off vents in my boat and have no problem getting on plane. The previous owner put bigger K-Planes on the boat and that did not help it actually made the boat worst on take off! If you bury the tabs all the way down on take off, you will actually lift the stern of the boat adding more air to the underneath.
#32
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From: Washington, MO
this may be just another stubd queston and may not mean much hear with theas boats but has any dealer R&R the drives lately ? at the rear trim ram pin with the black caps covering the nut's there is a white plastic spacer in between the nut hard wear that could be installed wrong and it will change the drive trim angel a bit not leting the drive tuck in as far.they do this becouse there is a differents between bravo 1 & 3.and some guys will change that around by not knowing where to put it.on bravo 1 the spacers need to be installed with the grove part pointing a way from the bow of the boat or a way from the boat in general. well i'm shur it's fine but if not it a easy thing to look at any ways.it dose sound like the x is high but that is where the top speeds come in.you would think the manufacturer,s would by now say to you oweners to install lower unit drive spacers by now to help stop the blow out. merc dose sell them spacers also.just an idea is all this is.good luck and have fun this year boating.
Last edited by 4mulafastech; 03-28-2009 at 11:01 AM.
#35
On a step bottom boat on the rear pad there would be two 1/2 or 3/4 brass thru hull openings that runs through your engine compartment out the transom or sides, They will have shut valves so if they leak you can shut them down. What happens on take off excess air gets trapped in the padded area and causes excessive prop slip and blow out. The Blow offs get the air thats trapped out from under the boat and reduce the slip from start.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
#36
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From: IL
#37
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From: IL
On a step bottom boat on the rear pad there would be two 1/2 or 3/4 brass thru hull openings that runs through your engine compartment out the transom or sides, They will have shut valves so if they leak you can shut them down. What happens on take off excess air gets trapped in the padded area and causes excessive prop slip and blow out. The Blow offs get the air thats trapped out from under the boat and reduce the slip from start.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
you will see on the back of a lot of number 6 Drives these 2" black tubes coming off the back of the drive and they come up over the drive, this does the same it release the excess air from a step bottom boat and reduces prop slip. Helps the boat get on plane faster.
Thats why I asked what kind of boat and does she have a pad on the rear of the boat.
the boat is a 2003 powerquest revenge with a small pad
#38
this may be just another stubd queston and may not mean much hear with theas boats but has any dealer R&R the drives lately ? at the rear trim ram pin with the black caps covering the nut's there is a white plastic spacer in between the nut hard wear that could be installed wrong and it will change the drive trim angel a bit not leting the drive tuck in as far.they do this becouse there is a differents between bravo 1 & 3.and some guys will change that around by not knowing where to put it.on bravo 1 the spacers need to be installed with the grove part pointing a way from the bow of the boat or a way from the boat in general. well i'm shur it's fine but if not it a easy thing to look at any ways.it dose sound like the x is high but that is where the top speeds come in.you would think the manufacturer,s would by now say to you oweners to install lower unit drive spacers by now to help stop the blow out. merc dose sell them spacers also.just an idea is all this is.good luck and have fun this year boating.
I've had that exact thing happen after having a drive worked on with the Gun. It definitely can be overlooked, and made my boat cavitate like hell until it was swtched back.
#39
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From: IL
this may be just another stubd queston and may not mean much hear with theas boats but has any dealer R&R the drives lately ? at the rear trim ram pin with the black caps covering the nut's there is a white plastic spacer in between the nut hard wear that could be installed wrong and it will change the drive trim angel a bit not leting the drive tuck in as far.they do this becouse there is a differents between bravo 1 & 3.and some guys will change that around by not knowing where to put it.on bravo 1 the spacers need to be installed with the grove part pointing a way from the bow of the boat or a way from the boat in general. well i'm shur it's fine but if not it a easy thing to look at any ways.it dose sound like the x is high but that is where the top speeds come in.you would think the manufacturer,s would by now say to you oweners to install lower unit drive spacers by now to help stop the blow out. merc dose sell them spacers also.just an idea is all this is.good luck and have fun this year boating.
Thanks for all the replys!
#40
A friend had a 34' PQ that also has the 2 large steps. His drives had spacers on it when he bought it. Possibly for this very reason?
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Some people are like Slinkies - Not really good for anything, but they
bring a smile to your face when pushed down the stairs.



