Nice upgrade, Rob. Hey, don't be such a stranger. Give us a shout out if you are around town.

Only the IMCO SC upper uses the B1 gimbal. The SCX needs a different gimbal from what I have read. My SC Upper bolted right up to my B1 gimbal.

**Edit... I was not up to date on this thread. Looks like the B1 gimbal can be modded to fit the SCX. Cool to know. The guy I bought it from had the IMCO gimbals.

I heard that. I am always thinking the the back of my head since I have a single and still run the XR upper gear train in my IMCO SC upper I may have to get a tow. AND I don't have good cell coverage on a lot of the lake we have a house on. I have a handheld baofeng VHF radio though fortunately that I can get a tow from a couple of the marinas on the lake. If I had the money, I would be running an SCX upper with the -3 SC lower I have now and also be making about 150 more HP. I would love to wake my boat up like that sometime.

Will do!

The SCX requires changing the helmet (or bell housing as some call it). That is the part that the drive actually bolts to. In Rob's case, we also had to change the gimbal ring. Mercury has 3 different gimbals. They have the HP, Magnum, and standard. The HP uses SS pins to retain the helmet and has a thicker gimbal ring for increased power. It is used on the "blue" engines and most diesels. The magnum is basically a hybrid. It uses the HP ring but not the SS pins to retain the helmet. The standard gimbal uses a smaller ring and has 2 bolts that thread into the helmet to attach it. With the HP and the magnum, you don't have to change the ring to install the SCX helmet. However, the magnum has to have the ring drilled and tapped to attach the SS pins since it is setup for the 2 helmet bolts. The standard gimbal requires changing the helmet and the gimbal ring. This is what we did in Rob's case, since he had the standard gimbal. Even though we had to change the ring, it was a great idea to change it anyway. That ring is not recommended with that kind of power.

I've attached a few pics to try to explain it better.

The first pic is the threaded bolt used to retain the helmet in the standard and Magnum transom assemblies.

The second pic is the SS pin used to retain the helmet in the HP transom assembly

Next is a pic showing the difference in the Mercury helmet and the SCX helmet

This shows the holes that we drilled and tapped in the gimbal ring to accept the SS pins. You can also see the original 2 holes that were used to attach the trim sender. The HP gimbal doesn't have a provision to use the electric trim sender (at least not a direct bolt on), since most guys running an HP gimbal have a mechanical indicator.

Does anyone else worry about the upper pin in the transom assembly?

All of it :drink:

We have swapped out the upper pin for IMCO's pin on a few. We always check the gimble ring for play. In all the ones that I've seen that have some play, it's the ring itself that is worn out, not the pin. I've never seen a pin break before the ring. That's not to say it can't happen. Anything can and does happen.
Eddie