IMCO Lower Questions
 

All of my boating experience has been with Mercruiser MR and Alpha drives. I just bought a Velocity 260 that has a Bravo upper and an IMCO lower. I have a few questions for you guys familiar with these drives....

By the pic I have included does this appear to be a stock or shortened Drive?

Second question, why is the skeg so damn long on this thing?

I understand the water pick up is in the front of the drive as opposed to being on the sides, so a different water fitting is needed when running on trailer. Outside of that what other special care needs to be taken with these drives, if any?

I was told that the upper was just rebuilt with XR gears and the lower is rebuilt as well. With my previous alphas the props were very easy to spin by hand. This drive is not nearly as easy to spin by hand....... I can spin it but it is very firm. (when I tried to spin it it was below freezing, so I am sure the lube is a bit on the stiff side.) Is this normal for a freshly rebuilt bravo/imco? Will this eventually loosen up a bit? I was told, by the marine that sold the boat, it ran thru fine in both forward and reverse..

Thanx in advance!!

http://site.activesportsunglasses.co...velocity_3.jpg

It should have -2/-1 stamped in the case if it's one of those. That skeg does look long for a Imco...You can buy the nosecone kit from Imco or Teague to run it on the hose. Looking at it I'd say it's a shorty, but very hard to tell from pic. Look up on the top of the case for the marking..These drives are no different that any other drive. Only difference in Bravo is drain plug is behind the prop. Oh and obvious fifference the impeller isn't in the drive..

Wash that thing would ya ;)

That is a Merc Sportsmaster lower not an IMCO
http://mercuryracing.com/drives/brav...portmaster.php

Griff is correct it is a Sportmaster lower.. looks to be short one.
A fresh rebuilt drive will be stiff for a while. I would suspect the cold lube is more of an issue at this time. Dont worry about it, try it again when it is warm.. When you get 50-100hrs on it.. the prop will spin freely..

Hope that helps.
Dick

Send a closer picture of the driveshaft housing (upper) it looks like a standard cap also looks like a spacer between the D-shaft housing and the gear housing.

Already been washed. That was after a cross country trip from Vegas to our lovely sate of Michigan...

Yup, I'd say by the pics your are spot on. Is this drive bettwer or worse than an IMCO. Reason I ask is it was advertised as an IMCO when I bought the boat....

There is a small 1/2", maybe 3/4" billet spacer between the housings. Ny ideas whay that is there?

Thanx again!

The spacer was probably added to help make the short lower work. The reason to go with a shorty is to end up with less drag. If you raise the propshaft too much, you will have a hard time getting on plane and possibly holding the bow up at speed. If you go up 2" and it doesnt work, the easy way is to try spacers to lower it until you get good results.
It is possible that this combination is tuned and at it's best. Let's hope so.
I dont have any experience with the Sportmaster ver Imco lower. They both move the propshaft up. Weather or not one is hydro dynamically better than the other is hard to say. I know the sportmaster costs more, because it is a Merc. They essentially have the same internals..
I remember early on with the Sportmasters, they would loose the caviation plate. Keep an eye on it for cracks. The Imco bolts on with a larger surface in contact with the upper housing cavition plate.
Hope this helps..
Dick

Like Mr G said, not a big difference between the Sportsmaster and Imco. The Sportsmaster does have a much longer skeg. Both have the same value and strength.

The spacer may have been added to bring the lower/prop back down a little. That looks to be a -2" lower and it may have been too high and hard to get on plane or had too high of a prop slip.

With a stock 496 mag in a Velocity 260, is there any advantage to having this Sportmaster -2 lower?? Or should I consider selling this fresh unit and put a stock lower back on it?

Took a close look at the lower unit this afternoon. It has a 1" spacer. It is also stamped 02H187 1.27:1 P1SG19. Guessing 1.27:1 is the gear ratio.. Is this the correct gearing for a 260 Velocity? Also measured 8" from top of lower case to center of prop shaft.

Teague said a few months ago in his tech article that the IMCO was a faster lower than the sportmaster that you have.
I think what you have is better than a stock length lower, plus you already own this one. No real reason to change what you have.
I would want to take that spacer out to see if it is needed for how you boat. It may be that the previous owner wanted more of a water-sports boat than one that was setup for speed. The deeper the drive is the better it will be for slow speed stuff like dragging kids on a wakeboard & such.
It is possible that Velocity sets their motors high in the boat & the spacer & shortened lower was needed to get the correct drive height.