Set Up Help 11' Tunnel

[moomba]

I have this 11 1/2' Tunnel with center pod splashed from a Liberator that I need some prop help with. I have not run the boat yet. It is all ready for paint and then I need to rig it. The bare hull is around 200 lbs. I have a 4" jack plate going on it. The motor is a 83 60HP Evinrude twin cyl. powerhead Compression is 140lbs. The 15" mid and lower is from a 1987 40HP. It does have power trim and tilt.

I am going to install a nose cone and Low water Pu. so the motor can be run high. Any thoughts as to a transom mounted wtr pickup instead of the coned lower. The gear ratio is 2.42 to 1. It is a premix motor now. My weight is about 175 lbs and the boat will be center steer.I'm not sure what kind of RPM's these motors will turn as I have only run Merc v6's. I have a JSRE 260HP on my STV Euro. Any and all help would be great. Below is photo of motor and the boat when I bought it.

Thanks
Steve

[MN1]

I can give you some Sport C info. Our 40 hp Tohatsu's have a 13:25 gear ratio and we use Merc Hub Cleaver11.25" to 12" dia x 18" pitch props. No low water pickup and no nose cones. My motor is set at 5/8" above the bottom at 3 degrees trim. Our race weight is 675 lbs.
Hope this helps,
Mark N

[Infoless Racer]

Mark, what would your engine be running at ? 6500rpm? Assume your rev limited is off.

Steve, I am also toying around fitting a 50hp Tohatsu on a Dillon Pro tunnel (11' @ ~220lb). will probably turn a 11-1/2X20 w/o nose cone or low water pick-up, just plugged the upper holes of the water intake and see where that takes me. If I don't get the water pressure thru the engine I will install the low water pick-up instead.

[MN1]

I don't remember what we saw in RPM's. But I think it was around 7300. I heard others were turning 8000 but maybe that was all (SMACK)
Mark N

[Infoless Racer]

Wow 7300!! That puts you close to 60mph.....how hard can you run the engine before it disintegrate?? At 7300rpm you are at least 25% above the recommended operating range!

[moomba]

Mark, what would your engine be running at ? 6500rpm? Assume your rev limited is off.

Steve, I am also toying around fitting a 50hp Tohatsu on a Dillon Pro tunnel (11' @ ~220lb). will probably turn a 11-1/2X20 w/o nose cone or low water pick-up, just plugged the upper holes of the water intake and see where that takes me. If I don't get the water pressure thru the engine I will install the low water pick-up instead.

Would you do a LWPU off the transom or do it with a cone??
Thanks
Steve

[Infoless Racer]

Well I am thinking along the lines of off the transom, a simple aluminium water pick-up welded to a bracket and connected to the flushing connector should do the trick. Seen that in the Formula Race hulls.

[JohnsonM50]

Well I am thinking along the lines of off the transom, a simple aluminium water pick-up welded to a bracket and connected to the flushing connector should do the trick. Seen that in the Formula Race hulls.

Ive got some 'go fasts' with both low pick up & transome mount.




The foot adapt is good because the water shoots up to the pump w/o a hose.
The transome mount does the trick but is more risky & has to be taken loose to remove the motor or tilt it up. The hydro has a good place to drill it in but I had to make the runabout one. Id call the low pickup best because you know its in the water. Running the indicator stream forward to where you can see it from the cockpits a good way to be sure.

[Infoless Racer]

Yeah, absolutely right to have sufficient hose slack to turn and tilt the outboard. A fancy alternative to the tell-tale stream is a cheap water pressure gause. :-)

[JohnsonM50]

Yeah, absolutely right to have sufficient hose slack to turn and tilt the outboard. A fancy alternative to the tell-tale stream is a cheap water pressure gause. :-)

A gauge is good, on the slack note: not too far off center helps