I installed Whipple Superchargers on my 454 mag's with Bravo 1, 1:50 drives. With that I wanted to run higher pitched props. I went from 25p Mirage to 28p Hydromotive Q-IV's. I changed to the Q-IV's right after installing the Whipples. I tried to put the Mirage props back on just to see how the boat would handle and they wouldn't go on all the way. I measured everything to find the interference but it all looked good. Then I took a closer look at the splines and they are twisted. The Mirage have splines closer to the thrust ring and bind up before seating. The motors are stock except for the Whipples that put out 5 pounds of boost. Not that big of a deal. I don't come out of the hole hard and haven't hit anything. I'm can't believe the motors would have enough torque to twist the shafts. Anybody else have this problem?

Yep, on the driveshaft splines just after the coupler. I have not had a propshaft twist though. You may want to concider a replacement. It may just pop and take your prop and part of your lower with it.

Ray,

Thanks for the advise. I think I'll make replacing the shafts a winter project, just have to stay out of the throttles for the rest of the year. I see that they make a heavy duty set of gears for the Bravo's. Do you know if rebuilding lower units is only for the highly skilled with special tools or can a guy with shop tools and a manual figure it out?

Roger

I am sure there are those that will disagree, but..... I know a guy that made his own Bravo tools in his garage, pulls & rebuilds Bravo's, gimbals, engines, etc all the time. He has no formal training of anykind marine wise. I don't believe he has ever had a "project" break down except by hitting something. Therefore I have to say, if you maintain cleanlyness, have a manual & good memory & mechanical aptitude. You could probably do this. Another guy in my office does outboards engines & drives. Again no training.....just manuals to guide him. It can be done.
I don't think I would do it myself if I had a Mega-motor behind it though!! Have fun. Remember, if it's broke now, your not going to break it worse doing it yourself.

YOU COULD GET PULSE DRIVE'S TRIMMABLE SURFACE DRIVE WITH A STANDARD SQUARE TANG AND A FIVE YEAR WARRANTY ON THE WHOLE SYSTEM. WWW.PULSEDRIVE.NET THEY HAVE SOLVED THAT AGE OLD PROBLEM.

FRANKIE

Had a friend who twisted the prop shafts on his bravos a few times on his 43 BT. Funny, he was using hydromotive props too.

Thats interesting. A guy from Hydromotive tried to talk me out of using their props but he was talking so far over my head I didn't get it. I wouldn't have used them but I got a deal on a set that I couldn't pass up. Most of the other people that have single engine Checkmates think they are great. With the twins I get too much stern lift. Otherwise they have super mid range acceleration. I think I'll change the prop shafts and try a set of Mirage 27p or 29p next year. I'm not happy with a top speed of 81 and I max RPM at 5000.

The pulse drive looks like an expensive change over.

A DUAL PACKAGE CHANGE OVER WITH A FIVE YEAR WARRANTY IS ABOUT THE SAME PRICE AS ONE OF THE UNITS YOU ARE RUNNING NOW WITH THE UPGRADES TRYING TO HOLD THEM TOGETHER NOT INCLUDING YOUR NEXT FIVE SUMMERS OF REGULAR REPAIRS. WHAT ARE YOU DOING THIS WEEK END, FIXING OR PLAYING?

OK, where can I look at one in the Chicago area or west Michigan.