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TBroccoli
04-28-2004, 03:51 PM
How do I find out the gear ratio of my BRAVO 1 outdrive? Its on a 1996, 22 Classic, 454 Magnum. Also, tach only showing 4200 rpm at WOT, with 23P Mirage Plus. Why?

Donzigo
04-28-2004, 11:46 PM
Gear ratios are usually printed underneath the sticker on the bravo on the left side. I'll bet cha it's 1:50 to 1. Almost 100% sure of it.

boldts
04-29-2004, 12:10 AM
I have a feeling you have the 1.36:1 Bravo1 gear ratio. Only reason I say this is because I have a 22 Classic with the 454MAG and Bravo1 with the 1.36:1 gear. Until I changed my prop, running a 23" Mirage prop, my top RPMs were 4200 to 4400.

Check the info Donzigo gave you first. If it is a 1.50:1 gear, you've got a problem elsewhere. A 23" on the 1.50:1 should be turning 4800 plus. Could be a number of items ranging from a tune up of the engine to maybe even a tach problem. Just curious, do you have a GPS speed to go with the RPMs reading. If your running 65 to 70 MPH, I'd lean towards the tach as the problem.

If the boat is slower than 65 and the engine is in good tune, I'd bet you have the 1.36:1 gear in which a change to a 22" Turbo1 will make a fantastic difference.

TBroccoli
04-29-2004, 08:15 AM
Thanks Donzigo. I found the gear ratio. It is 1.5 to 1.
To Boldts -- I have no gps or regular speedo. I believe my regular speedo tube is clogged. I bought the boat in December, had it out twice. It runs great and I can say it is the fastest I've ever gone on the water. But am still very courious of top speed. I want to make sure it is set up correctly. I'm hoping the tach is incorrect. Previous owner was supposedly meticulous with maintaining engine and appearance. I agree with appearance. Fresh awlgrip in 2003 along with all new interior. Not convinced yet with mechanics.
Thanks for the help. I will keep you posted.

Ranman
04-29-2004, 08:34 AM
Two things come to mind.

First, are you trimming the drive up to get maximum speed and RPM at WOT. If I leave my drive at full down, I only get 4500 RPM's and mid 60's speed. Trim her up and watch the tach hit 5100 at 70+.

Second, The sticker on the drive that says 1.50:1 may or may not be accurate. It may be possible that the gearset in the drive was changed and the sticker was left on the case. The only real way to tell is to rotate the input shaft and count the rotations on the output shaft. This would be similar to determining the rear end ratio of a car (turn the drive shaft and count one tire rotation).

Good luck with the boat.

TBroccoli
04-29-2004, 08:43 AM
Good point Ranman. I'm still a little sissy driving the boat at this point in time. The drive has been all the way down. I tried to get use to the trim tabs the last time out. I almost threw brother and father right out of the boat. If the weather hold up I will be out again this weekend. Learn more try more. Thanks.

Ranman
04-29-2004, 08:59 AM
You are about to discover what your Donzi is all about! Take your time and be cautious,

If you are leaving your drive all the way down, I can almost guarantee this is why you are not pulling full RPM's. You are also not seeing the last 5 to 9 MPH out of her either. Optimal trim is where the dirve is up as far as it can go without slipping.

Start at a medium speed and begin to pull the drive up. As the drive comes up, you will literally feel the boat loosen up and begin to run "free". You will also pick up RPM's without touching the throttle. If you go too far with the trim, the motor will continue to pick up RPM, but the boat won't pick up any more speed and may even slow down. This is your prop slipping or losing its bite. As soon as you see/feel this start to happen, bump the trim down just a tad. This is the optimal spot.

On my Merc trim gauge optimal trim is at the 1/2 way point on the gauge. This is not true on all boats and may or may not be the case with yours.

Lastly, as you trim up the drive, the boat becomes loose so be careful. As Harry Shoell said to Cole Trickle "Loose is fast... and on the verge of out of control."

Good luck with the boat and let us know how you make out.


Methinks the Broccoli is in for a surprise...

Sam
04-29-2004, 09:38 AM
Just as an FYI, I have a 22" Turbo that I'm selling. It's just not enough blade for my current set up.

Sam

Donzigo
04-29-2004, 10:23 AM
Ranman gave you good information. The initial offerings of the Bravo 1 in about 1987 or so, were indeed 1:30/1 (sorry Bolts, not 1:36/1) and when they began running the 454's on them, the Bravos sometimes would burn up. Mine did, that's why I heard about it. Ranman is right, but the change would have probably been to the 1:50/1 from an earlier ratio.

boldts
04-29-2004, 11:56 AM
Sorry Richard. I was talking replacement drive gear ratios not original equipment gear ratios. No biggie. Looks like TB has found the needed information and the reason for low RPMs.

Sterndrive Unit Part Number Ratio Your Price (new / reman)
Bravo One 5 - 5120136KZ 1.36 $4500 / $3800
Bravo One 5 - 5120150KZ 1.50 $4500 / $3800
Bravo One 5 - 5120165KZ 1.65 $4500 / $3800