pinkpanther

How do I get my boat to stop chine walking at 60-65 MPH? I have a 509 with a blower and a bravo upper with a Imco lower. The prop need to be lower pitch sicne the place I bought it from just threw on a 34P. I think it should have a 26 or 28P. Let me know what you guys think. This is my first fast boat.

Irishtornado

Does it have hydraulic steering? Does it have Kplanes?

pwam1

First, external steering is an absolute must for this much power on this small of a boat. Since it sounds like a singlr. Is this a 24 Outlaw? A lot of the chine walk is probably due to a bit of play in the steering. K-planes as IT indicated as well.
I wouldn't do much with the prop until you get the boat to settle down. A 26 and likely a 28 will be way too small.
Are you out of power at 60 to 65, or just haven't been able to drive thru the chine walk?

Smitty

iTrader: (1)

Check for slop/play in the outdrive. Try to lift it up and down and twist it side to side. If there is any play that is why it chine walks.

Also as others have stated, get external hydraulic steering immediately. You need it to keep all that power under control.

And I would start with the 28" pitch 4 blade prop AFTER you add steering and find the loose points on the gimbal.

pinkpanther

No external steeing yet! Does have drew maine stabalizers. Top speed was 65MPH on gps at 3900 Rpms. Wouldn't pick up any more speed. Tried to trim it up some and it got a little loose. Does have trim tabs. A buddy has the same motor is a 26' cat and is turning a 30P. I heard I could put on an extension box and it would cure it?????????

fastscarab22

iTrader: (1)

Things just dont add up, lets say it was a mag cam stock before build up so 365 hp plus blower 100 hp that makes 465 . lets make it 500 hp . do the math you should be able to run that prop if you can get it to plain off to 70 or better, the problem it getting to 5000 rpm or better is there rev limiter that is stopping you, can you rev it over 4300 at idle for i second or two just see if it will do it, you can always try a differnt prop , but the rpms is the problem . you have the power to spin 30 plus blade . might not be the best top end blade but you should see over 4300 rpms . rember all tachs , lie. a stock mercriuiser rev limiter is 4250 or 4350 on a mag motor. put smaller blade on it and spin it up and see if it hits a rev limiter

Smitty

iTrader: (1)

For point of reference-- I had a 95 24 Outlaw with a Whipple charged 454 Mag. It ran a best of 76 mph with a 26" Bravo 1 prop. You do not have enough power right now to spin a 30" or a 34" prop.

Irishtornado

What I wanna know is why the rev limiter is said to be set at 4300-4650? This is not where Mercury sets the rev limiter on any of they're BB setups...It should be at 5100-5200 and prop accordingly. If your only spinning that motor at 3900rpms your way over propped..You should be spinning it @ 5000 rpms to acheive where you want to be.

Smitty

iTrader: (1)

Rev limit on the Mag MPI motors is 5150.

JerseyOutlaw

You'll never cure it in a 24', you have to drive the boat, don't let it drive you. I bought my OL in 05 and it took me a good 2-3 yrs to get a real good handle on chine walking, now I can hold WOT and steer through it, practice. I know of a 25OL with a xbox, imco, 24" K planes, and hyd steering, and still has to drive though some chine walking. All those things will make the boat alot safer but it won't 100% cure it, always be ready for it, because you can get hurt. I am doing steering and K planes on mine this off season. Good Luck.