Jet height on Mod V with center Keel?

[rotus623]

So, got a 2000 Merc 60/40 Jet, short shaft and a 1999 Polar Kraft Mod V (6 degree deadrise) with center keel.

Issue I am dealing with is I have an untouched transom (no mounting holes) so I don't want to make swiss cheese trying to get my mounting height right. I am also considering either tunnelling this hull or trading this out for a flatbottom jon.

Anyways, Outboard jets says to measure up for a V hull and to mount at height A:



BUT I have a center Keel. If I did not have a center keel then I would expect to mount the engine at the red line. I am thinking since I do have a keel that I should mount the engine somewhere between the blue line (the height of the keel) and the red line. What would you guys think?





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[LarryMc]

Judging from your photos, as center keels go, yours is not that big. It doesn't look as big as the one on my Lowe and I didn't include the height of the keel on my boat when deciding how high to mount my motor and mine works fine. On your boat, I don't think you should include the center keel height either. IMO, if you mount your motor so that the leading edge of the jet intake is between the red line and the blue line as shown in your photo, it will be much too low.

 

[rotus623]

Larry,

Thanks for the reply. The keel is pretty small. Should I trimm all the way in to for a baseline on how high to set the motor? Or trim it to 90 degrees?

Looks like you have a mod v also. Did you set the first grate pins at about the red line?

 

[LarryMc]

I trimmed mine all the way in to set the height. Outboard Jets recommends setting the height so that the leading edge is even with the bottom of the boat, so that's what I did. I measured from the outside edges of the intake to set the height which puts the center a little above the bottom of the boat. If I set mine very much higher, it tends to cavitate in rough water. You might be able to set yours up higher, but the only way to know for sure is to try it.

 

[rotus623]

I trimmed mine all the way in to set the height. Outboard Jets recommends setting the height so that the leading edge is even with the bottom of the boat, so that's what I did. I measured from the outside edges of the intake to set the height which puts the center a little above the bottom of the boat. If I set mine very much higher, it tends to cavitate in rough water. You might be able to set yours up higher, but the only way to know for sure is to try it.

Cool, thanks I think you are right. I guess its time to get the drill out

 

[handyandy]

you should be able to drill one set of holes and move the engine up or down a inch just by changing which holes you go through on the engine's mount.

 

[rotus623]

you should be able to drill one set of holes and move the engine up or down a inch just by changing which holes you go through on the engine's mount.

Thanks, yea that will give me adjustments in 3/4" increments. Worse case scenario I would oval out the mounting holes to get fully capable adjustments.

 

[JL8Jeff]

you should be able to drill one set of holes and move the engine up or down a inch just by changing which holes you go through on the engine's mount.

Thanks, yea that will give me adjustments in 3/4" increments. Worse case scenario I would oval out the mounting holes to get fully capable adjustments.

I wouldn't oval the holes, you want the bolts to be good and tight in them to make sure they are sealed off and moisture can't get in. Transom wood usually rots out from the inside so keep the bolts as snug as possible. The mounting bracket holes should give you enough adjustment to find the best spot. My boat already had a 40 hp prop outboard bolted to it so I had to use the holes that were already there. I still have one more hole I could go up if I needed to but I already tried it and got too much spray back.