What's the weakest part of a Bravo 1?
 

Just curious as to what you guys have broke on your Bravo 1's? What's the weakest link? What seems to wear out first? I'm thinking about installing some Imco gears instead of stock replacement Merc gears. I'm hitting mine with a 540 with 574hp and 590 lb. ft. tq.

Don't have a Bravo, but from reading the forums, it sounds like upper gearsets, gimbal rings, lower gears, vertical shafts, and propshafts, probably in that order. Flywheel drive couplers seem to be a frequent offender as well.

The teeth break off of the upper gears. Doesn't matter whos gears you are using, it is just a matter of time before they break.

Chevydog,
There is a long history of the Bravo drive. There have been alot of weak points over the years. A lot of them have been addressed by Mercury and aftermarket. Depending on what year drive you have, it will have different weak points. Early ones before 2000 had thin floored gears, they would push the floor out of the upper driven gear. The XR gears were brought out to replace the helical in high torque situations. They did very well up to about 3-4 yrs ago, they started snapping teeth off. I have gone back to recommending the helical cut gears unless the power level just cant handle it.
The gears that everyone sells that fit the Bravo's are Merc gears and have the same issues.
On the older upper cases, the towers would warp and crack below the surface and fail, the steel tower fixed that problem. Tell us what boat you have and what you want to do with it.. recommendations can be made. If your boat is a lighter weight, then the helical gears would be the way to go.
Hope that helps.
Dick

The nut behind the steering wheel. Sorry, had to.

Avoid hole shots and try and match re-entry rpms when jumping.

Very interesting thread as I am about to be in the same position myself. I have been told that many failures happen when cruising at 3500-4000 rpm and the "nut behind the wheel" goes to WOT under peak engine torque.

I was going to say the Throttle Arm:coolcowboy::drink:

Mid range torque can be a problem with a low hp engine if not applied correctly.. But in the old days the gear lash was very loose.. A properly setup B1 can handle quite a bit. On a 700hp engine, NA, the low end torque is less than a 450hp motor.. so you can strain them either way.
I used to beat up my 25' Checkmate with 502, 690hp and never broke the drive. More cubes and bigger boat and ouch..
Applying torque has to be gentle. And when the prop comes out of the water, you have to match the rpm on reentry.. other wise things get stressed..
There are alot of guys around here that run the B1 and have power and fly the boat on Lake Michigan and their drives live, not forever, but a good long life. And the better a throttle guy you are, the longer they will live..

Thanks for the info Mr Gadgets. Real world experiences really help....so much to learn.