IMCO Extreme SC Upgrade Project.
 

I started to install my new IMCO Extreme SC Drives on my 98 Powerquest today. I started by inspecting the units all looked fine but one lower unit I decided to send back to IMCO. It seems to be under a bind when turining the prop and upper shaft CCW. if you turn it CW it rotates fine. A wierd problem??. The other I assembled the lower onto the upper and replaced the rear cover with the existing latham rear cover to accommodate my steering.

The only mod I have to make is to cut off the flange at the bottom of the existing bell housing to provide clearance for the cooling tube that is routed down to the lower unit. Then mount as usual. I will post other pictures and procedures as I get them done.

Looks real good - can't wait to get mine. Only I didn't get mine polished because I didn't want to draw that much attention to the drives.

Wow - problems on one out of 2? Kinda making me scared - mine's due in within a couple weeks. :rolleyes:

You say the gimbal ring has got to be mod'd in order to fit the drive on?

Kook,

Yeh I was a little shocked too but better safe than sorry.

The cut you make is to the bellhousing itself (shaded area in red) You remove the bottom most flange on the bell housing not the gimble ring

Forgot to post pict:

Update
 

I pulled my gimble bearing and seals on the transom assembly. One was shot for sure the other seemed fine but I will replace it anyhow. I sure am glad I bought the proper tool from merc for pulling the bearings, They were quite hard to get out I really had to crank to get them out. I also have the bearing insert tool to put them back in.

One thing I did'nt expect to see was the bearing sets at an angle in the carrier. At first I thought they bent when they were pulled but after checking out the new ones I seen they were angled too.

I have had more concerns about the new IMCO SC Drives. I dont want to bash the factory as they have been very acommodating so far. If you are interested in the problems I have seen let me know and I will E-Mail you.

The problems you are having - are they related to the complete imco drive or just the lower? I am getting just the 2" shorter lower and using my internal parts.

Tinkerboater - You have Mail

New SC Drives
 

How are your new drives? I have a set coming any day for a new 31 AO. Hope I made the right choice.

I also am expecting my pair by noon Wed.
I ordered the 2" shorties with the 1 1/4 shafts in the 1.348:1 ratio with polished lowers.
I would like e-mail also if still available.
Thanks Mark.

I had a few suspected problems but everything is fine, I have about 10 hours on the drives

I had a binding issue on one lower unit and some shavings in one upper. The binding was because the lower was not mounted on the upper and the thrust bearing was moving up, the shavings were thought to be machining spirals that "accidently" got inside the drive. Check out this link, near the bottom I have details about the problems. http://www.offshoreonly.com/forum/sh...threadid=19744 So far they have worked great.

How much power are you pushin through them?
I see you have the 28"s on there...What speed and rpm is it turning.
Hope thats not too personal of questions:D
BTW, they are here and they are spectacular!
I noticed some weld circles on the lower...maybe from manufacturing?
Here is a pic of the 2"shortie lower next to a stock Bravo.

The weld circles are normal, Mine has them too, They get worse when slightly corroded. Just keep it polished. I am going to try the Zoops seal and see how it works to keep them bright. The 28's I have were severely cupped and running like 32's. They are at hydromotive right now being re-worked. I tried a set of 30's last weekend and was turing about 400 RPM higher than the 28's at 50 Mph. I have not had the chance to do a speed run yet with the 30's. I maxed out the 28's at 81Mph at 4500 RPM But I need to spin them faster. When they get back I will test agian. My engine builder says I should be running 1.50 gears as to not load up the drives. At this point I am still testing and IF I need to make the change I will.

Here is a link to recent postings: http://www.offshoreonly.com/forum/sh...threadid=27482

I am running about 680 Hp into them. So far they have been great.

Spots on drive..
 

Back4more
I also have the heat spots, I have tried just about everything to get them off, have done a lot of buffing and polishing,they are still there. Guess that if you can see them"you are to damn close!!"
If you find a way,let me know!!

eliminator219

New drives
 

I am going to be running 125 gears with 30 props to start with. We go to the dyno next week with two new 540's that should make 800 plus easy. The new sc drives came in wednesday and look really nice. Hopefully we will be in the water in a couple of weeks.