Just broke another 1in merc shaft on my Bravo 1X... I was thinking about upgrading to the IMCO 1.25in but I am worried what else will break if the 1.25 shaft don't. Should I upgrade or not ?

The question should be, why is my propshaft breaking?? Where is it breaking and is there any twist in the splines on the other drive? Are you airing out the boat? Normally the 1" can take a lot of punishment. It used to be a two piece welded shaft, not sure if it is these days or not. What props are you running? 4 blade?

It broke the same place as the last one, right where the tapper is by the outer seal.. The boat did air out a couple of times during the weekend but when it broke we were just cruising. Both times I felt a thump then the tach jumped, like it hit something . Yes the props are 4blade Bravos .. No twists on the other side..

to high of a xdem, prop is vibrating
.

What does that mean ??

im saying maybe your drive is higher on the transom, which causes a vibration which u wont feel but the drive does and it causes that, does your boat throw a rooster tail, most dont unless they run a high x dem, and when the drive is deep in the water we over trim to get the cool rooster which in return causes broke drives usually the rh standing at the back of the boat.

Yes it does throw a rooster tail. I guess that could be that. It is the right side.. I would think the 1.25 shaft would help stop it from breaking.. I also think upgrading one side for now would be fine, Am I thinking right ??

i would go with the 1.250 shafts on both drives,no reason to keep bying 1 inch shafts&props.

I plan to upgrade both during the winter. I am just making sure I could do one at this time and run it.. I cant see why it would hurt anything ..

yes 1.25 shafts also but if they braek right at the splines i think there the same at where the frt bearing goes. and thats where i broke mine.