Hey guys Im new to the site and looks like a lot of great info here. a little about myself, Im originally from NE Iowa right on the mississippi around pool 9. basically live on the river hunting and fishing. I am going to be building my first LT in the very near future. Right now I am in the design phase and as much as ive been searching I havent found anything to really compare builds to so I want to ask whats the biggest motor anyone knows of thats been built? Im looking at a 125+hp 3 cylinder 4 stroke engine. one of the biggest obstacles im facing right now is shaft length, and prop size. I know there are numerous other threads about these two topics but all that I have found are for smaller engines and boats. so.... anyone piping in on their thoughts would be great. I understand shorter lengths will turn better and vice versa, but I also want to get a good balance for the tail and engine since it is such a large motor. right now I have the shaft length around 8ft....? thanks guys and I will post progress along the way.

What does that engine weigh? What boat is is going on?

gonna be a bitch to turn

Did you already look at the Harley LT? I would think it would beet the piss out of you but I would like to see you do it

im going to start it out on a 20 ft flat. more than likely its going to stay on that boat, maybe strong maybe, it would go on a 18ft. I did see the harley LT, it appears to have a pretty short shaft on it. which is why i was kinda second guessing myself to see if i should really go as long as I was thinking. the motor itself really isnt too heavy I can carry it myself, but after the tail, cooling, and oil tank is added it will be a chore for sure, but I am confident it will weigh less than the 4 stroke merc outboard that is currently on the boat.

Have fun turning it

Saw rambo's latest movie and he was manhandling a big ass long tail, but he is fukn Rambo.

Good luck with it man. Post back and let us know how it goes.

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Its been about 3.5 hrs since you posted this. Are you done yet? Got any pics so far?? I think 8' is too short.

Here's a pic of a zipper's big block long tail to give you some ideas. You should get the frame off of eBay. That way your halfway finished

thats cjb's uncle he suppose to be gettin us raffia...

i know they said the harley motors were good in a straight line but horrible other than that id hate to see trying to turn on that big

I was gonna say earlier, take a look at those ebay kits I heard they are the bees knees....

I will work on getting a screenshot of what im thinking for layout for you guys today another quick question to get the gears turning, is there any other function other than leverage for the longer tiller arms?
my thought is with the right balance of the tail and motor I will be able to run a shorter arm, helping the shittyness of what the turning is going to be. but to keep you all coming back heres a picture of the power plant.

here is where im at for layout so far. the exhaust is going to be turned shot out the back not the front after the collector and intake is probably just going to be some K&N cones. still need to decide what length shaft, what length tiller arm, where to mount oil tank, and how to make the engine and mounting pivot.

Would love to hear a backfire on that. You should also put a flame rollout kit on it so you can shoot flames out of the exhaust.

Here is quackshots VW longtail on jon boat. Fella that built it only ran it half throttle, one would have to guess that it's got plenty of power. lol

http://s80.photobucket.com/user/akaquac ... o.mp4.html

Thanks for posting. It will run around 30 mph with 2 people. It is on a 1546 express

Schohtime
Im looking forward to seeing your completed build it looks pretty cool. Where ya from in NE IA? I originally grew up in McGregor, left in 89 and after years of bouncing around ended up in Alaska. Good luck

Schohtime
Im looking forward to seeing your completed build it looks pretty cool. Where ya from in NE IA? I originally grew up in McGregor, left in 89 and after years of bouncing around ended up in Alaska. Good luck

RUCK - Im originally from Lansing, just a quick jump down the river to McGregor. its definitely a small world, im actually heading to Alaska next month for work.

If those skinny Asian guys can steer those LT riverboats, so can a well fed Yankee! You'll need a big cooler up front full of ice and cold ones for ballast/balance.

Have you ever thought about building a surface drive instead of a LT? I would think a SD would be be easier to steer with that big of a motor. I found some pretty cool SD plans online if your interested PM me a email address.

Shorter tiller handle = harder to turn

That long shaft way out there with all that torque has a lot of leverage on you, a long heavy boat like yours will also be notably harder to turn. It'll take a lot of force on the tiller to turn that rig!

Try running a hydraulic pump off the motor. Split it to a bidirectional two way valve to a hydraulic motor to turn the shaft forward or reverse. and another to a bidirectional 2 way valve to a steering cylinder. Also might use a prioritizing valve for the two circuits. You could make this stick drive like a outboard and get all the torque and speed if flow and pressures are correct. Just a thought.

brasso- it was done it UG, luckily I happen to know one or two people that are good at "missappropiating company resources for personal use" lol

coupe- I hadnt considered hydraulics for forward and reverse, I did consider coupling the rear end and just making a linkage to basically add a rudder to aid in turning. unfortunately im not a very patient person and I cant wait to get this thing on the water so I may just make the basic solid shaft to begin with so I can some hours on it, and then when the snow comes up here in the great north pull it in the garage and begin to do the mods. at any rate thanks for the idea.

looking at a 3/4" cold rolled drive shaft, 1 1/4" housing with 3 bronzed bushings, a bearing at the top of shaft after UJoint. any suggestions?

thanks for the shaft recommendations i will let you know what we end up going with.
Sorry Brasso UG is short for Uni-graphics, alot like pro-e

Ruck- I got your SD plans this morning, after looking at those I think a SD project is inevitable hahaha. I think Id have to beef up the drive system a bit instead of the v-pulleys but i got some ideas muahahahaha.

What's the steepest angle that engine can run. I'd find that out if not already known because there's only so steep you can have an engine like that before you starve the front cylinders of oil. A u joint maybe be necessary to keep it at a suitable operating angle.

yeah I plan on mounting the engine vertical and running a ujoint, possibly two. it looks like the most common shaft angle is 15* which is a added variable as to why I was going to go with a longer shaft.