Have a 13Hp predator engine. Using Mad Motor build plans. Motor will be going a 12 36 or a 14 48 flat bottom. Prop is from hill marine it is an 8x4 or 8x5. thanks for any sugestions

Any pics

No. Still trying to find pipe that is 1in. ID for my bushing's. D.O.M tubing is a lil more expencive than what i thought it would b. everything i have found is just a hair to big for my bushings, witch wouldnt b a big deal i can work around that but i run into a problem with my seals.
any sugestions?

It has to be DOM or seamless tube, which is even more expensive than DOM. If it has a weld bead on the inside of the pipe your bushings will become deformed when you drive them in.(ask me how I know).Also your seals will not seal if there is a weld bead in the tube.I have built 2 of these with the same plans, so if you have questions ask away.

I had thought about taking a dremel and notching the middle bushing so it would slide down the weld, and a deburrer to smoth the weld on the 2 ends so the bushing and seals would go in. What are ur thoughts on this JSS3?

I tried it...exactly what you are talking about. I was able to grind the bushing and drive it in with no problem. It was when i tried to push my shaft through I had a problem, it wouldnt go! I tried twice, both times same outcome. I may work out for you, but my advice would be to save yourself some time and money, bite the bullet and buy some DOM. Find a buddy who wants a motor too and split a stick of tubing, thats what i ended up doing. It was $150 for 22ft so $75 a piece. Where are you located?

Im in northeast Texas. Where did you get your dom tubing from?

General Steel, its a local place. I found a guy out of North Carolina that would sell dom by the foot. He built race car frames if i remember correctly. If you cant get any I could ship you some, but it would probably be cheeper somewhere local after you pay for shipping. Any machine shop or metal supply can order it, you just gotta find someone who is willing to help you.

What size motors did you build JSS3? Did you run into any other problems in your builds?

Both with 6.5's, I built one of them so it probably has 9 or so horsepower. Add another grease zerk just below the autoluber to fill the shaft with grease. The swivel mount in the plans is junk, so i came up with my own. My auto luber started leaking where it treads into the shaft, using someones idea on here I was able to fix it with a 1/8 mpt coupler. Here is the tread.viewtopic.php?f=6&t=28152

the way the swivel mount in the plans looks very simple, so im sure there can be much improvement.do you have any pic on the way you built your swivel mount? I plan going the way the plans say for the most part on this 1st build, unless i see something i can do better from the start. I have a 13 hp and a 6.5 both being shipped and will be here next week, i plan on building LT's out of both of them. what size boat did u put yours on? i have a 12x36 14x48 and a 12ft water moccisan pirgoue. i want to put the 6.5 on my pirgoue but i think it will b way overpowered, what r your thoughts?

My motor is on a 12x32 and does 14 mph with 1 person, but is about useless with 2 ppl, way too slow. The 13 will probaly do good on the 14 ft boat, I think it will be too heavy for the 12. As for the pirgoue I would stick to paddles and maybe a trolling motor. There is not enough room in a pirgoue too operate a LT safley. Also I'm not telling you the swivel in the plans will not work, it is what i used at first, but it had alot of slop in it. The swivel I came up with could be improved as well, but does better than the one in the plans.

Online metals.com 50 bucks for a 72in dom

Here is my swivel look under my posts to see my mud motor build

Sorry here is the swivel mount and transom mount

Looks good, do you have any pics of the complete motor?

No i have been bass fiishiin so i havent finished it yet

thanks for all the help. got my DOM tubing ordered last night so hopefully i will be able to get started on the build next week.

I've built a couple, one with the 13hp predator and one with a 16hp maxtool.
YOu can get seals online at mcmastercarr, or at BearingService and Supply in Shreveport. Probably someplace like it in Texarkana.
THey have in stock a LOT of seals, and one that will fit your tubing and shaft. I even got a man at bearingservice to cut my keyway and thread the shaft.
Be careful to only weld a very short strip at a time, as too much heat will warp your tubing lengthwise, and shrink the inside diameter of the tubing, either of which you don't want to do.
I'm building another in the next few days. I agree, the madmotor swivel bracket is a piece of junk. I made my own, too.
Good luck,
Monster

just got to put it in the water today. Its runs great! having a problem with the 3/4 shaft spinning in the yoke, and the other yoke slipping backwards. was thinking of drilling through the yoke and 3/4 inch shaft and putting a bolt through it. on the output shaft was thinking of putting locktite on the keyway and set screw and c what happens. besides that and having to figure out a better pivot mount its great. any advice on the few problems would be great!

Im not sure I follow you when you say slipping backwards? Are you saying the yolk is moving on the output shaft towards the engine? I do know drilling through the output shaft isnt a good idea, the shaft will not be able to hold up with a hole in it. I know what you are talking about as far as the spinning inside the yolk, I went through the same thing, first I added 2 more set screws to the yolk and that didnt work, then had a key way cut into my shaft, but kept sheering keys, finally i broke down and welded the two together. I really didnt want to go this route but it worked, I put only 2 small tacks on them and it has held. I did this so it would be easy to cut off and grind smooth if i had to replace a seal or something. It goes without saying only weld one yolk!
Did you use the 6.5 or 13?

I used the 13hp. the yoke on the output shaft was slipping back off the shaft. I found the set screw was loose this morning wile looking it over, not sure if it vibrated loose or i forgot to tighten it, had a little to much help last night while finishing everything up. lol. I put loctite on the keyway and set screw, and it held up fine while running it today. on the 3/4 inch shaft i took a drill bit that would fit inside the threads of the set screw and drilled into the 3/4 inch shaft about an 1/8 of an inch. then took a grade 8 bolt that would fit without sticking out of the yoke to much and sharpened the end with a grinder, loctited the bolt in and welded the shaft all the way around. i tryed to put 2 tacks on it with the set screw that came with it last night, like you did, and it sliped. i think the 13hp was to much for the small tacks, and my welder is only a 110 volt so i dont think it burned in good. if something happens i will just have to replace the whole shaft and yoke i guess.
ran it today after fixing everything, put the GPS on it and it would push my 14x48 12mph like it was nothing, would run 15mph if i put the prop deeper in the water, and the GPS said 18.8 on the max speed, i reset it when i got on the water, after i found out it would go 15 i put the GPS down and didnt look at it till i got off the water, i couldnt hardly belive the 18.8!

Im glad you got it worked out. Sounds like Im about to build a 13hp, that is some good speeds. Did you change anything on the plans? What prop did you go with?

IMG_8742.jpgthe prop is a 8x4 hill marine. I went with 1 inch flat bar for braceing instead of the 3/4 like in the plans, and made the base plate, cavation plate and skag a little biger. i was having the cavation plate bent yesterday, so when i ran it it was without it, gona take it out today and see how it does with the cav plate on it, after seeing what it did yesterday without it, i dont see the point in a cav plate, may have a diff story after this morning.

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cav plate killed my speed, went from running 12 -15 to a flat 10mph, and a top speed of 14.5 v.s 18.8 like B4 without the cav plate!! think i need to raise the cav plate about an inch. any sugestions????

is the plate running under the water ? it may just need some adjusting . mine works best if the plate is riding above the water, my prop is just before blowing out. In deep water I have to push down on my stuck slightly and in shallow water say a 8 inches or less I have to pull up on it.In a foot or so of water it pretty much will drive itself.

it is running on top of the water. when i ran it without a cav plate, the prop was deeper under the water and i was running faster, with the cav plate at full speed i cant get the prop deep enough to get my origanal speeds. with the cav plate on top of the water the prop might be 2 or 3 inches under the water, where before it was close to a foot under. in my area we dont have a lot of shallow water it is mostly stumps and grass that i have to worrie about, most water i run is 2+ foot deep, not including a sand bar here and there, the deeper water i run in maybe affecting me more with running the cav plate.

Post a picture of the cavation plate. It sounds like the back tab is bent too far down and needs some adjusting?

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Bend the back tab up and it will keep it from riding too high in the water. You also need a nyloc nut on the end of you prop shaft bub.

X2!

ok. will get the nut replaced, and bend the tab and try it ouf the afternoon and let yall know how it does. thanks!

your cav plate is way too big. cut the surface area in half. no wonder you lost that much speed, half of the cav plate is blocking the water from reaching the prop. and there is no reason for it to extend beyond the prop.

get a torch!

bend it up and whack it just at the backside of the blade. Over time youll prolly slim down the profile of your frame to reduce uness. weight (not judging craftsmanship) it looks damn good and sturdy. Before long youll be so hooked you be 20k+ into a suface rig like the rest of us

thanks 4 the advice, will try it as soon as i get another prop, mine just snaped off the shaft right were the threads started!! How common is this? I had a buddy over looking at my setup and he said he towed a guy in off the water one night that had snaped his prop off his Lt. i have been running in deep water (2-8 Ft) havent gone through any mud or anything to dammage the rig, have hit a few small limbs in the water (1/2 inch in dia. or less). havent had any vibrations like anything was outa ballance, the shaft was done by a machine shop outa 3/4 cold rolled. the only thing i can think is maybe the prop became loose and had a lil play, and when i put it in the water and got a load on it it spun the shaft into. cant aford many more of these mistakes or losses whatever the case may be. ANY SUGESTIONS?!?!?

next shaft go with 4140 stainless steel.

thats what my machinest said when he came to get me outa the river. but i would still like to know how often this happens