Outboard Jet Tilt Setting

[smackdaddy53]

I am working on modifying an aluminum hull and would like some collective insight on what setting to have my tilt pin on my Merc 60 Jet. If I let the motor tilt all the way down to the stop the measurement from my transom to front of foot is 10" and the pump is angled down slightly causing the rear of the foot to be 3 1/2" lower than the front of the foot. That would cause my tunnel to be a little too shallow at 2 1/2" deep per outboard jet specs. If I tilt the motor up one hole the measurement from transom to foot is 12" and the rear of the foot is about 2 1/2" lower than the front and that looks better in correlation to how deep my tunnel is. It also makes the pump pretty much level with the bottom of the hull.
My dilemma is that I cant run the boat yet because I have fabricating to do on the float pods and tunnel and don't know which setting will work best.
How does the pump/foot sit on all of your jets? I dont want to make the tunnel too far back and then have to let my motor tilt down one notch and be hitting the top of he tunnel and I don't want the foot sitting below the hull or I would not be adding a tunnel. Pictures of your transom/motor side views would help a lot.
Thanks guys

 

[smackdaddy53]

Anyone?

 

[catmansteve]

I haven't messed with a tunnel before so I can't say from experience, but I would set it up for having it trimmed all the way down/in. You want to keep the option to trim it all the way down for that day you bring an extra buddy or cooler along and need a little extra oomph to get on plane.

I don't know if you've seen James River Jet's tunnel design, but I think they add an extra piece of flexible material from the lid of the tunnel that sticks out past the transom. It's basically a flap that rests on top of the foot when trimmed out and bends up out of the way when trimmed in. This, in combination with intake fins, lets you set the motor height a little higher than with just the tunnel alone.

Like I said though, I have no personal experience with tunnels, I've only ever looked at one custom-built tunnel in person and it was done by James River as I described. The boat owner was a member on here, Bretr, I think he has a thread with pictures of it buried somewhere back in the jet forum. Might wanna check into it further.

 

[catmansteve]

Found it, tunnel pics at the bottom
https://www.tinboats.net/forum/viewtopic.php?f=48&t=22385&start=15

 

[smackdaddy53]

That was my thoughts, always leave room for adjustment. I will fabricate the tunnel to fit the foot at the lowest setting and just add a flap if I need to trim it up.
Thanks