Planing Issues....
 

3 month new 1999 ao 26 nsx owner here. Power is a 496 dyno'd @ 585hp. Stern Power outdrive w/ 1:46 gear ratio.I bought it with a 26P prop. Extremely responsive once on plane, especially through 3500-5000RPM range. However, it takes a while to plane. In fact, one trip I had 6 adults on board, and I had to get everyone in the back to stand up foward for it to plane. I have read where these 26's should plane around 3 seconds. Well, I spun a blade off a couple trips ago. My mechanic had a lab finished 28, which I guess after lab finishing, props drop a pitch. So, last weekend I had this '27P' prop on. Had 4 adults on board. EVERYONE, including me had to stand up and lean forward for it to plane. Plus, it took quite a while to plane. 7-8 seconds, maybe more. The boat didnt perform well with this prop once on plane either. So I know now I cant go up a pitch. With my 26P, I was able to hit about 68mph@5500. According to the previous owner, in the dead of winter in Lake Havasu, the boat will hit 90. I know the redline is 6200rpm, with the 'sweet spot' around 5800rpm. Back to the issue at hand, can anyone please take some time to provide what ever insight, or advice you may have as to why this boat is having a difficult time planing? It really doesnt make sense. With the hp , and how tight the performance is w.a 26P - it seems like this boat should plane relatively quick and with ease. Thanks alot.

Re: Planing Issues....
 

the 2600 and NXS , both plane very easily with bravo drives and the correct X dimension. I'm not sure where you're x is sounds as though it has been put very high for high speed, the downfall is they don't plane easily when they are high. you might try more prop blades.

Don

Re: Planing Issues....
 

I know it seems obvious but you could use your trim tabs to get on a plane or drive trim could help, dropping a degree or 2 of pitch should help get on plane faster but hurt top end.

You may want to find a marina in your area that demos props and try a few.

Re: Planing Issues....
 

If the X-dimension is too high, maybe a drive spacer or extension box will help.

Re: Planing Issues....
 

I think that props would be a great start, but with sternpower drives I think the props are hard to come by.

as far as an extension box or drive spacer, also same problem. Stern drive is a great system, however can use a system extension box or spacer without alot of fabrication.

Don

Re: Planing Issues....
 

Props are not a problem on his drive. He is running a bravo style prop. on his drive.

Re: Planing Issues....
 

I dont have trim tabs. But, I have been seriously considering it. Thanks to all. My lower unit on my drive resembles a bravo drive, and I have a BravoI 4 blade on it. Speaking of blades, someone mentioned maybe using a prop with more baldes. Would a 5 or even 6 blade prop help?

Re: Planing Issues....
 

CA southpaw-- Check your P.M. box. Later, Scott

Re: Planing Issues....
 

littledcsrodshop ...

have you had an AO, or familiar with the stern power drives ?

Re: Planing Issues....
 

No american offshore. However I am a little familiar with stern powr drives, I have a MX-107 on my 28 Pantera. Me & CA southpaw have been talking back & forth about his.

Re: Planing Issues....
 

First are you blowing out the prop or is the rpm to low to get on plane? From your top speed it sounds like the engine is low on power to me. Something wrong! Not enough torque. Low compression most likely. Do a compression check to see where your at. Are you using gps for speed calculation? Do you know your gear ratio? If 1.5 you shoud be at 80mph with a 26 at 11% slip, 5500rpm. Make sure your outrdive trims in all the way. I wonder what the tilt in angle is on the unit. Maybe need a spacer to bring the outdrive in more.

Re: Planing Issues....
 

Parden my ignorance on the subject matter...but, my rpm's when getting on plane are around 2400-2900. Regarding my power, I know something isnt right somewhere. But, I doubt its the powerplant. Thing has 80hrs at most on a rebuild. 10:1 compression. I did a compression check before I purchased it and it was well above standard. Not using GPS. Gear ratio is 1:46. Regarding your assessment of the top spedd, I believe that is where I should be all day as well, from reading other topics on AO's that have far less HP than my motor. My drive does trim in all the way. It does have an extension box on it. The tilt angle, when its trailered, it actually tilts 'in' towards the boat. In other words, when looking at it eye level, from the side, the drive isnt exactly verticle to the ground, it actually is pointing a hair towrds the hull. Here's one more piece of info., the boat has a transmission in it. Which, I have heard robs roughly 10% power??? Not sure of it though. Thanks for everyone's time.

Re: Planing Issues....
 

Not sure if a visual will help. But, here's a couple of pics of my outdrive.

Re: Planing Issues....
 

Southpaw. See your PM's..

Re: Planing Issues....
 

My quikest answer is you cam is a little big for your set up. Lack of low end torque. Your speedo tube is getting a mixture of air and water causing it to read low.

Re: Planing Issues....
 

I had to run a longer speedo tube when I had mine. It was 5"s below the bottom. Otherwise it was erratic.

Re: Planing Issues....
 

Applying some common sense here leads me to believe this is the direction to start looking in. Because, when I had my 26P on, 6 adults, we all had to stand to plane. Even then, there were times where I had to give up, and try again, because it sounded like my engine was going to stall from the struggle. Last weekend when I had that lab finished 28P, 4 adults, we had to stand up. However, even then it (the motor) was still struggling. Struggling by bogging down as if it was going to stall.

Re: Planing Issues....
 

With a 26 P bravo 4 blade and 1.46 gears this boat will run 79 MPH at 5500RPM and require 480 prop HP with 6 people on board. Your 68 mph is incorrect. Borrow a hand held GPS and check the speed.

Motor should not lug when getting on plane. Sounds to me that the bottom end hp may be too low for 4 to 6 people on board. This could be caused by too large a cam.
How does it plane with only you on board and what is the speed and RPM.

Re: Planing Issues....
 

I think that's what I said.

Re: Planing Issues....
 

The hulls on AO's are not condusive to quick planeing. I have a 540 BBC. When I first bought the boat it had M1 procharger on it. At 2500 rpm's it would leap out of the water and as soon as the blower kicked in. That was with a 30pitch Bravo 1. Remove blower and fuel injection. Now running a 850 holley. I use the 30P for top end and 2 people in the boat. Takes me 8-10 seconds to get on plane. A 26P takes me about 5 seconds to get on plane. 80 gals of fuel and 4 people. Motor does not have low end torque. Also the boat like stock Bravo 1's. 15 1/4 diameter. Anything less and cavitation goes wild. I had the cupping removed and blades thinned out and it cavitates too bad to even use.

Re: Planing Issues....
 

I have an IMCO outdrive. 1.26 gears. 1.50 gears would help me some but I'd lose top end.

Re: Planing Issues....
 

Why not try a 24 4 blade for outings with guests. Your overproped for your set up with that many people in the boat. I have a 26 AO with a 598 running a B1 with 1.36's and a Imco shortie spinning a 29 p5X and she pops right out of the hole. I was running a Bravo 1 32 4 blade that would pop right out of the hole as well. Try a smaller prop with guests in the boat and I bet your troubles go away.

Re: Planing Issues....
 

born2burn. 5 blade works well? alot of money to spend to try a 5 blade!!!!! are you blown? i didn't know how to interpurt your last post.

Re: Planing Issues....
 

Yes true.......but tell me whats cheap about these animals. lol
OUrs is naturally aspirated.

Re: Planing Issues....
 

I read on Speedwake you were trying out a 30p bravo 1. How's it work out? I have a 30 Bravo 1 thats been worked down to a 29p and less cupping, will sell cheap if you can use it. I'm still confused. Naturally-asperated to me means carbed. Are you running a blower?

Re: Planing Issues....
 

NO BLOWER...........Yes naturally aspirated means carb.....one measly little carb. Havent tryed a 30 yet was going to try a 30 for just a cruzing prop.......or when I have a full boat load and full of fuel and use the 5 blade for the speed prop. Need a spare prop anyway.

Re: Planing Issues....
 

Thinned blades dont last on my boat. I need the thickness or it throws blades.

Re: Planing Issues....
 

Have you had it to 5800-6200 rpm or is that what the person you bought it from says the top rpm's are? If all you have had out of it is 5500 then by going down 2" of pitch yuu will plain quicker & gain about 300 rpm's on top.

Re: Planing Issues....
 

Not thinned(labed), just some cupping taken out, pitched down to 29. $100 plus shipping if you want it. Boy, your 598 must put out dome low end power....

Re: Planing Issues....
 

I will take it for a 100.00 can you send me some pics?
[email protected]
thanks
Todd

Re: Planing Issues....
 

Yep. Will take them tonight.