engine height

[evilrude 1]

I have a 14 foot thundercraft playmate that is extremely light (500lbs fully rigged) that I am looking for some set-up advice.
engine is a ported 70hp short shaft (stinger) aprox. 90+ hp.
I have converted the boat to external stringer and center steer. I am using cable/wing steering,foot throttle,solid mts, low water p/u and its on a 10 inch set back bracket.
At this point I am running the prop shaft 1 inch below the bottom of the boat.
I think the motor is too low (no rooster tail) but with a 19p sst prop it will rev to the moon and launch onto plane.
I also have a 22p raker and a 23p silver streak that I haven't tried yet.
Just wondering how high I should go with the engine as a starting point and what to expect.

Thanks in advance for any help/advice.:D

[dnelson964]

Sounds like a cool little boat. If you have lw/pu and your prop has some tight tip cupping I would try 1" above the bottom and see how you run. Of course I would also put a water pressure gauge on the dash because you need to watch the H2O pressure stays at a safe level.

If you want to start raising slower I would start even with the bottom and go up 1/4" increment until you find the best handling and speed.

Good luck !

[evilrude 1]

thanks
I was thinking at least 1 inch above especially with the 10 inch set back. I always run a water psi gauge
I'll be doing some testing this weekend.

[sharpeye Mike]

I would start by blocking the 2 highest water intake holes, then get a 12.5"x22"-23" cleaver of your choice. I would also start with less then half of your set back.
Mike

[evilrude 1]

Mike

I have low water p/u's---all holes are blocked.
10 inch setback has to stay---power trim is incorperated into it.
I know the set back is a bit extream but I think its workable as I'm never going to go 80+.
I've found cleavers are only good for flat out running as they tend to slip alot at slower speeds. (hard to find too)
Thanks for the reply though.

[sharpeye Mike]

I'm not sure what to tell you, I don't think you will be happy with your set up. Your 10" setback is normaly use on a boat that requires a helping hand at lifting the bow but I'm not an expert in this field.
My 75 hp Johnson ss powered Delta is mounted directly to the transom at 21" high, running a 12.75"x22"cleaver, it jumps on to plane at ease, can run at any speed and is a joy to drive.
Mike

[evilrude 1]

Just came back back from some testing with some really good results.
I set the engine prop shaft 1/4 inch above the bottom of the boat and spun the 14 1/4 x 23p srx silver streak to 6500 + rpm and the raker even higher!
I had to go back to my regular l/u with a nose cone but no low water p/u and only had 5psi water psi and the engine reached 180 deg's before I limped it back to shore. I am not only happy with the set-up I'm Amazed how fast this little boat moves out. I think with a little more set-up (trim is dead at this moment) I should be knocking on the door of 70mph (here's hopping !! )
My spare l/u (with l/w p/u) is getting some work done on it so for now I'm thinking about transom mounted water p/u.
Just looking for any input on installing these transom p/u's
Thanks in advance.

[71V153]

I should be knocking on the door of 70mph (here's hopping !!)Well, you can hopp all ya want but 70 mph is a a pipe dream. How fast is it now?

Don't suppose you'd have any pictures ...

[evilrude 1]

LOL---the word was supposed to be "hoping"

here's some pics
http://i807.photobucket.com/albums/yy360/trillium5/096.jpg

http://i807.photobucket.com/albums/yy360/trillium5/093-Copy.jpg

http://i807.photobucket.com/albums/yy360/trillium5/091-Copy.jpg

http://i807.photobucket.com/albums/yy360/trillium5/088.jpg

[evilrude 1]

and when I built it

http://i807.photobucket.com/albums/yy360/trillium5/mechanical/IMG_0473.jpg

http://i807.photobucket.com/albums/yy360/trillium5/mechanical/IMG_0468.jpg

http://i807.photobucket.com/albums/yy360/trillium5/mechanical/IMG_2260-1.jpg

http://i807.photobucket.com/albums/yy360/trillium5/mechanical/IMG_2259-1.jpg

I don't think it's a pipe dream !

[BASS HOGG]

sweet set up

[evilrude 1]

Thanks Bass Hogg
I see this is your 1st post!!
Welcome

[Cavit8]

sweet set up

Agreed! Nicely done.

[BigJohnson]

Nice! Looks fun.

[evilrude 1]

Thanks guys!!!
Its the fastest 55 - 60 mph I've ever experienced. Small boats always feel faster.
I'm also in the process of building a very light glastron GT 150 with a warmed-over 83-140 evinrude.
That's for next year though.

[200VEGAS]

thats a nice dam boat. it looks like it could use a 135v-4 bubbleback. although your motor sounds real nice and is probably worth more. i have a 26p laser small hub flo torque that might help hook that motor up. mr demeanor did a very nice and complete transom mount pickup and has a lot of pictures on his thread. very nice. you could talk to dah about tuning that silver streak for surface running and drop rpm a little and you would probably have a great prop

[racerx]

Bolt the motor to the transume,i bet it will drive a 100 percent better..let me know?

[evilrude 1]

Thanks 200 but I think a v4 would make this boat feel like a tank. This thing is ext light and narrow better suited to the stinger motor. I have a friend who owns a prop shop and I think I might roll the leading edge of the prop a bit' but the silver streak is very sluggish prop until the exhaust gets tangled up in there so I might just leave it alone. The glastron gt150 gets the 140 But that's another story.
As for bolting the motor straight to the transom I can't do this because I built a custom power trim set-up into the setback plate...and really its not too much of an issue as long as you pay attention to whats going on (or you'll be going over!!!) This things better than a roller-coaster !!! right now there is almost no boat in the water when going flat out but is still very controllable.