The size of the components used in a bravo drive would make a nice garden tractor transmission

ICDEDPPL I'll take 2 gallons of the Snake oil Please, maybe it will get me though the summer!! But I don't get upset when I blow my bravo, because I'm willingly sending more HP/TQ through it then it can handle.

not magic - good maintenance and you can get 80+ trouble free hours on them - then rebuild'em

Besides what everyone has said and not to repeat the same info. I have heard this this as well - hard runs then quick deceleration of the throttles along with coming off plane is very hard on the gears. Also IMO extreme thermal shock of the outdrive itself from on plane running then coming off plane completely submerging the outdrive in cooler water temps. This has to cause a lot of expansion and contraction of the complete assemble and at very quick moments going from one to temp to another. Saying this by means is not a gradual change in temps but dropping 20 to 50 degrees in a blink of an eye along with the weaker metals of today is just a killer. Just my 2 C's

I will agree the older bravo's held up better than currently. I also heard that around 1993 was a good Bravo drive to have.

this thread should be named "how many people are still in denial?" for every five people with failures there's that one die hard that says its the best thing ever. one even said just buy spares, carry them around and deal with it. how does that sound good much less fun?

Thanks, guys. I thought my OSO friends were supposed to enable my addictions, not point out my obviously poor decision making!

Well, I'll go the cheerleader route. Lots of guys out west running 800 with XR, I think the not jumping and throttle jockeying them is key. No doubt a ticking time bomb, but my last went 2 seasons behind 750 (then got sold and flogged on a 650 HP scarab after that, and then on to a 271 Formula after that and still in one piece.) My current XR is a Teague, 2 seasons on it with 800, 150 ish hours.

I run Bravo Shop oil, and cross my fingers. I somewhat baby the boat up on to plane, but then its on. Never gets put back on trailer without at least one WOT rip.

Just my experience, I'm sure everyone will disagree.

I don't buy the thermal shock explanation...I've run tons of tests on metallic parts in attempt to thermally shock them...I.e. Thermal ramp rates exceeding 400F in the matter of 20-30 seconds. We were never able to shock the parts. Why? Because the mass thermal inertia of the parts is too large. You put a small block of metal in the oven at 400F and then throw it in the freezer...the actual surface temperature of the block will slowly and I mean slowly go down over tens of minutes. Not seconds. If the parts we are talking about were tiny with no mass...I'd buy it. But we are talking large gears, shafts, etc. I'd be willing to bet once the drive gets warm the rapid cooling doesn't effect surface temps at all based on my experience. And the parts I tested are a lot smaller than the ones in bravo drives.

granted heating and cooling is faster in fluid than air...again ive run tests with fuel 40F to 275F...not much changed. And these parts have much tighter tolerances than Mercury. Talking 0.0001" Diametrical clearances.

I'm not saying I agree or disagree with his theory, but it as you pointed out the the thermal expansion/contraction is faster in low viscosity fluid than in air. Like MUCH faster. Don't quote me, but I seem to recall water is about 3,400 times more efficient than air in removing heat.

Another variable to consider is the outer case/housing on a bravo would be experiencing this rapid cooling, the internal parts (gears, bearings, etc) would be cooled at a slower rate after submersion in cool water. This internal/external delta could account for significant dimensional clearance and tolerance issues which might be enough to cause failure in a marginal product that's highly stressed and close to it's failure point to begin with.

Again, I'm not sure I think this is a major cause of failure, but the theory at least has some merit.