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-   -   -3 Imco shorty: who's running one? (https://www.offshoreonly.com/forums/drives-lower-units/221364-3-imco-shorty-whos-running-one.html)

ndaniels 12-15-2009 01:12 PM

-3 Imco shorty: who's running one?
 
I see Imco has a -3" shorty lower out. I called Imco and found out it'll work on the merc upper, but prop size is limited to 14-14.5". I was also told that a couple of guys had modified the mercuy upper a little to make room for larger wheels.


I know I could buy the SC upper for the -3" lower and not have any clearance issues with props- it has a step built into the upper on that model. Just wondering if anyone running one with the merc upper?

osur866 12-15-2009 01:27 PM

Not running a -3 on a merc upper but I'd think limiting yourself to a 14" diam. prop would not be too good of an idea on a raised prop shaft height, that doesn't give you many choices IMO. I'm running a -2 and with my set up larger diam. props seem to work best with the higher shaft height.

DonRoc 12-15-2009 01:30 PM

I have the -3 upper and lower. Love it. I may be selling the set up as it will not hold up to the new motor.

ndaniels 12-16-2009 01:32 PM


Originally Posted by osur866 (Post 3006304)
Not running a -3 on a merc upper but I'd think limiting yourself to a 14" diam. prop would not be too good of an idea on a raised prop shaft height, that doesn't give you many choices IMO. I'm running a -2 and with my set up larger diam. props seem to work best with the higher shaft height.

I was figuring that up to 14.5" prop would be ok. I'd think a mirage plus 27p or29p would work fine at 2" below the pad on my 21sb. Dunno, maybe I'm thinking too much like an outboard owner:grinser010:

I was hoping to see, or hear about what mods have been done to the merc upper for larger prop clearance with the -3 lower, in case I had to go that route.

DMOORE 12-16-2009 04:57 PM

I was told that the Merc upper needs to be modified to accept a -3 Imco Lower. Ya might want to double check just to be sure.


Darrell.

MDGperformance 12-16-2009 05:25 PM

The bravo upper needs to be machined out to have some clearance for prop,can only run about 14 diameter prop if not machined,did one for a 25 checkmate works great,any machine shop can handle the machining,or you could cut it out with saw and sand flat by hand

ndaniels 12-16-2009 08:11 PM


Originally Posted by MDGperformance (Post 3006954)
The bravo upper needs to be machined out to have some clearance for prop,can only run about 14 diameter prop if not machined,did one for a 25 checkmate works great,any machine shop can handle the machining,or you could cut it out with saw and sand flat by hand

Thanks, MGD!:kiss:

You got any pics? I assume that the stock merc lower can still be used, and it leaves a notch on the upper by the rear?

Do the -3 lowers come with any kind of cav plate?

Sorry for the ?s, but inquiring minds want to know!:drink:

DonRoc 12-16-2009 09:02 PM


Originally Posted by ndaniels (Post 3007036)
Thanks, MGD!:kiss:

You got any pics? I assume that the stock merc lower can still be used, and it leaves a notch on the upper by the rear?

Do the -3 lowers come with any kind of cav plate?

Sorry for the ?s, but inquiring minds want to know!:drink:

No, the cav plate is on the upper. The -3 uppers do come with a cav plate it turns up to clear the prop. I may have a picture

DonRoc 12-16-2009 09:07 PM

IMCO -3 Picture
 
1 Attachment(s)
This is the best I had.

osur866 12-17-2009 02:06 AM


Originally Posted by ndaniels (Post 3006828)
I was figuring that up to 14.5" prop would be ok. I'd think a mirage plus 27p or29p would work fine at 2" below the pad on my 21sb. Dunno, maybe I'm thinking too much like an outboard owner:grinser010:

I was hoping to see, or hear about what mods have been done to the merc upper for larger prop clearance with the -3 lower, in case I had to go that route.

Well you might get away with a 27p m+ at a diam of 14 3/8 but the 29p m+ has a 15" diam. I tired a 27 p m+ and it was a foul handeling SOB:eek:. I'm running a labbed 29p m+ but the diam. is 15" don't think that's gonna work for ya without some mods goodluck


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