gcsprayjr

A friend of mine has a Bravo III. While the power transfer is great on the B III, they seem to corrode badly. His fresh water trailered boat is always developing pits in the metal, and they cannot keep paint on the thing. That would drive me crazy just watching it. Our mechanic says the the Bravo I is the best outdrive ever made, and cautioned me about buying any other.

gcsprayjr

We seem to have worked out a system for water sports with our two boats without making any expensive mods to the boats. A big part of it is learning one's equipment.

First thing, is that some of our skiers have learned to deep water start behind the slower to plane big block. To be honest the skill of the skier has a lot to do with it. The rest of them just ski behind the bass boat which they are use to.

We have two tubes now, and the Mach 1 pulls them perfectly, since time to plane is not important. The tubes are four person each, although we limit each tube to two riders each. The old Mach I lumbers around pulling the tubers without breaking a sweat, where the two large tubes are a challange for the bass boat to pull safely.

Thanks to all for suggestions.

At some point in the (probably distant) future, I want to do a complete rebuild of the Mach I making a GFBL wannabe out of her. I am thinking a custom re-gelcoat, Eagle on the bow deck, and interior, with an Amarican Flag theme. The seats will be red and white stripes, and the sunpad will be blue with 50 stars on it. For power I and leaning towards a 572 Chevy crate engine, marine of course, and a B 3 outdrive. Right now it is just a dream.

apollard

The BIII will provide a heck of a holeshot, and pull like an ox. However, it provides another benefit besides just the increased hookup on the props - it give a lot of lift to the stern. That allows me to plane my 26' Powerquest in about 3 seconds, and hold plane at 12 mph (gps). Great for watersports, and I still get 56-58 mph top end depending on weather & water conditions (300 hp 7.4).

A healthy 572 will give you the torque you want and in a 22' perhaps the the low speed planing ability. But, it will be more expensive than switching outdrives.

If someone is having problems with corrosion on a BIII, they need to check the Mercathode system - it it is not working, the paint will blister and pit. Ask me how I know

Carbon Footprint

iTrader: (4)

I loved the BIIIs I had on my 280ss, pulled hard out of the hole with 350s and climbed all the way to the top @ 55mph in Denver.
Does anyone know why they are not used more on performance boats? Is it that they are not as strong as the B1, or do they have issues when the speed reaches more than 60 due to increased drag.

apollard

I've always heard drag, speed for that varies by person giving the info, but seems to be somewhere in the '60s. They are also reverse rotation, and so get hotter than a std rotation BI, so a good drive shower is a plus when running high speeds.

Dennis Moore

The most bang-for-your-buck (the original question) would be a camshaft change. The camshaft used in these engines is the same camshaft used on the 396/325 horsepower Impala, Chevelle and Camaro engines from the late 1960's.
The camshaft has 213/217 intake/exhaust duration with a wide 114 degree LSA. Not a very powerfull camshaft for the late 60's, really not a powerful (or modern) camshaft for a 1990 boat engine.
You would see a real performance increase with a modern Comp Cam and no drawbacks as far as fuel consumption and idle quality. I suggest a camshaft with 218/224 intake/exhaust duration and a 110 LSA. You will be pleasantly suprised.

Install a modern dual plane high rise intake manifold (retain the stock carb) and throw the MSD ignition overboard (re-install the stock Mercruiser Thunderbolt IV for best performance).
Use RV15YC4 Champion spark plugs gapped at .045 and a K+N flame arrestor.
Good Luck
Dennis

A.O. Razor

A 572 will tear the B3 apart. So yes, it'll be expensive. And don't think a XR will make it better. A 600 hp 572 pushing 600+ hp and torque will detonate the B3 pretty fast.

Get an Arneson #7M

Many have. There is more to it than the Mercathode system. Too much steel. Also, if someone is in your habor, and has a screwed up electrical system, he can be a huge problem too,

It's not that easy.

apollard

Well, owning one that is not corroding now, yes it was that easy. Know of quite a few others with no issues also. Stray electrical current from bad installations are another issue.

gcsprayjr

It sounds like a 572 is too much engine. I may be better off to have the 454 built with a forged crank, roller cam, rectangle port heads, matched intake, and be happy with those mods only. As for the MSD/Thunderbolt ignition, it has been flawless so far. Our mechanic swears by them.

Right now, we are just going to maintain the boat and enjoy it as is. A 7.4 in a 22 footer with a 1:50 ratio B1, and a 17 x 4 Revolution prop is is sprited ride. I will not be making changes until repairs are needed. I figure that once it has to be repaired, I might as well add some mods to it. Since it has 360 hours, is stored on the trailer in the garage, and is only run in fresh water, it could last a while.

A preventive for corrosion on a B3 may be fairly easy, I don't know. What I do know is that when we were boat shopping, I only looked at fresh water boats, and there were many B3's with lots of corrosion problems. One friend of ours who keeps a boat dry on a lift at Lake Wylie SC has been fighting this issue since his boat was new in 1997. I have driven the boat, and it does out perform my boat on holeshot, however my boat out performs his boat on top end. The two boats weigh nearly the same, and have the exact same engines.

His boat has no shore power, inverters, or other items that can cause stray power. His dock is at least 250 feet from the nearest neighbor, and his boat is out of the water on the lift when they are not using it. Why the thing is corroding, nobody has yet to determine, including Mercury Marine.

During our boat shopping, our mechanic, who also provided our survey, told us that the B1 is the best outdrive available. It is easy to maintain, simple to repair, and pretty much trouble free. He strongly urged me in the direction of the B1 as first choice. So when we found the time capsule of a boat we have now the choice was clear. We had found our next boat.

A lot of this stuff is learning one's equipment, how to use it, and what to expect from it. Once the operator has an understanding of their boat, it all gets easier.

endeavour32

iTrader: (4)

If your interested I've got a BBC with 50 hrs on it that puts out 525 hp and around 525 +/- tq that I'm selling for $6000.00. It was professionally built by Wesco Racing. http://www.wescoracingengines.com/
You could sell your engine for $3000 or so and for $3000 have a far superiour engine. I've got it for sale in the swap shop and all the specs are listed there. If your interested or have questions let me know.