How to Make a Mud Motor/Air Cooled Outboard

In this video, I discuss the design of my mud motor, made with the leg from an old outboard, in combination with a harbor freight lawn mower engine. Total build cost was just over $100, and everything works very well. I will try to answer any questions you might have, but remember, if you wish to share a negative comment, you'd better have the experience to back it up. Please like, comment, and subscribe. Thanks for watching!

[@austinsmith1815]

Would love to see some footage of you on the lake to see how well is moved the boat!

[@austinsmith1815]

Nvm just seen your second video thankyou!

[@gosttunter]

Ditto!! Me too!

[@jeffreyoglesby806]

you can pull the governor if you take the side cover off the block it is just a plastic gear inside the motor. We used to race go karts and you can do a lot to the predator engines

[@joeblowjohnny2297]

Make sure everyone who is contemplating on using these low rpm motor for this boat motor project to always use a 2 blade PROP and keep your pitch at 10-14 max pitch depending on HP of motor or you will burn them up . You need to bring rpm up on these motor to get proper speed with a 2 blade prop or you will over work these motor with bad fuel consumption and burn it up ........ hope this help ?

[@BandiGetOffTheRoof]

You're my new hero...haha. I love the shifter...might want to tie a lanyard to the pliers.

[@ardysmith9987]

If you go belt drive instead of direct drive you can spin the propeller fast two cycle engines turn up higher RPM your lawnmower will only turn up 3600 where a two cycle will hit the magic at 4500 to 5000 RPM . The first one I made like this was in 1985 I've made about 20 of them . I also use 90 degree gears to make my own lower units . Yours with brake because the bolt is going to snap you should have made a collar using a lawnmower blade holder an welded it to your spline collar ,then very important stress relieve it in oven at 400 degree for 2 hours.

[@tomjeffersonwasright2288]

To join the shafts, grind one into a square, and weld a socket onto the other, grease well. I ran an old 3 hp evinrude that had that rig to replace bad splines. The socket was on the crank's end, and the drive shaft was ground to fit the square drive..

[@cadolf3]

tom jackson That's an excellent idea! Never thought of that. If you watch my second video, you'll see the newest setup I have

[@midwestguy761]

tom jackson i

[@jonclark9757]

Great idea!!!!! Mudbuddy did have this with their Sport V and Sport H models, and sure you are familiar with the problems. The idea of a very powerful mudmotor (50hp and above) also relates to torque, especially in the mud. Will subscribe to your format......good luck, and thanks for showing us your invention.

[@MrEngineman69]

Just unhook the governor and the engine will idle down,you would need to add an idle adjustment screw for minor adjustment.thats what I did

[@Lanninglongarmmowing]

This is really cool. I have wanted to do something similar to my mercury 7.5 HP motor. It won't start and is a pain to get running again if you get it started. Lol. I wanted to use that same motor too. Great video!!!

[@cadolf3]

I really appreciate the response! It was a blast to build. I don't get to use it much (my Triton TR21 is much easier to use LOL). I will say, the HFT engine is NOT reliable. It's very difficult to start. If I were to replicate this project, I would find a used riding mower for $150-$200 and use that engine with electric start. Update video coming soon

[@Lanninglongarmmowing]

Charlie Adolf, III No problem. I'm sure a lot of people would stop to talk to you about the motor if they saw it. Sorry to hear the motor isn't reliable. Won't it start when hot? All the motors we have from harbor freight are pretty good and we are happy with them. I've seen people do what you want to with a riding mower engine. It's a little loud though.

[@cadolf3]

Hot or cold, the engine is quite difficult to start. If a riding lawn mower engine were to be used, a muffler could be fabricated from the exhaust down into the water as a silencer. This isn't a "quiet" engine by any means. At idle, sure. But when revved at all, it's just as loud as any other engine

[@christofercantley6240]

Cool stuff Charlie, cheers from Canada ! :)

[@cadolf3]

Thank you! I've since had it on a test run and it did very well. Update video coming soon.

[@G56AG]

There are a number of videos on You Tube showing how to remove the governor. Keep in mine this engine is optimized for the governor, if you remove it, and consistently run it at higher rpms, it will shorten the life of the engine. Some people have reported the flywheel has self destructed at higher rpm with the governor removed, so they recommend replacing the flywheel with an aftermarket model designed for higher rpm, billet aluminum models are available.

[@christianespinoza985]

Dude cool asf lol I never thought of this💯💯💯👍🏻

[@djfoxalaska]

Well done.

[@gosttunter]

Will any lower leg work????

[@jaymacklin8303]

Man that's pretty cool ,good job!

[@cadolf3]

Thank you very much! It's been a work in progress. School and work has been getting in the way of doing an update video, but I will try to make one soon!

[@slickwillie3376]

I wanna do something like that for a dual outboard cat, to limit the salt water corrosion problem as much as possible. I'm thinking that more powerful air cooled engines might do the trick. What think?

[@mrbojangles9841]

How did the predator hold up? Would you recommend after having it for a while?

[@gosttunter]

Great question mate.

[@billsmith8238]

Nice video, saved some serious cash too. good job. Planning on building one also.

[@TheMustangStampede]

you now have lawn mower outboard not a mud motor but good job man.

[@krat0us]

I got the 5.5 predator mower but having trouble finding lower ends. Any advice?

[@gosttunter]

Apparently you didn't get any advice the shows. I'm try to do this too. Ugh

[@bulletproofpepper2]

good one. Thanks for sharing.

[@huxmetalworks7371]

Great job thanks for sharing

[@xJgrayx]

did you put a cast flywheel on it in order to run it?

[@cadolf3]

No sir, these newer engines don't require any additional mass to run properly.

[@xJgrayx]

@@cadolf3 awesome thanks for the info

[@Louisxs650]

I think the exhaust of the original motor goes out throughout the centre of the prop to help for speed. The prop will turn easier if it's rolling on air bubbles than just water. Don't quote me on this I'm not 100% but I believe its something I've heard of a while ago. Maybe do some research on it?

[@pennynelson4377]

Louisxs650 what about polluting the water with the exhaust? or does that matter at all toyou

[@Louisxs650]

Penny Nelson lol News flash Captain Planet, all outboard motors and inboard motors (basically 80% of boats) exhausts under water. And no I don't care. That motor is a 4 stroke and doesn't pollute nearly as much as a 2 stroke motor, which most outboard motors are.. But you don't know anything about that do you. Do your research before you attack people with stupid comments.

[@Louisxs650]

Penny Nelson the new motors still exhausts in the water.. I don't have time to waste arguing with a liberal fucktard like you.

[@fbksfrank4]

Louis come on.... take one for the team.

[@kyleranderson1948]

Penny Nelson Bro you dumb as shit. New motors defenitly exhaust into the water, I haven't seen a new boat that hasn't. And you should see my old 70s two stroke... You've never seen smoke bubbles under water until you've seen that. It's not rocket science so figure out your shit before you put out your half assed comments on how your not the dumbass because clearly you are.

[@stevexxmubarak121]

Nice how much cc or hp

[@retiredoldsarge5938]

you can actually just put a couple zip ties on the governor control and stop it fro working. Thats the fast easy way.

[@dakotabeam2530]

If it’s air cooled then why have it in a bucket of water ?

[@alexanderjoseph1918]

good thingking

[@johnlebony4569]

How long did the fuel last?

[@cadolf3]

John Lebony it was surprisingly economical. I can get about 2 hours out of one tank.

[@johnlebony4569]

Wow that is pretty surprising considering the size of the tank.

[@MrKoladge]

Looks good but you can run it all day out of water with no problem.

[@SuperBigRol]

Where's the update!!!

[@gosttunter]

Ditto!!!! Did it fail ???? Update needed !

[@shanerogers5469]

Why do you have it in water it's not water cooled

[@richydoubler7640]

did you have to get a title for it

[@cadolf3]

backwoodsfishingtrapping the boat already had a title and registration, the motor doesn't require any legal paperwork in Florida

[@richydoubler7640]

ok

[@retiredoldsarge5938]

hold the camera still... I am about to fall off my chair...

[@stevesmith6058]

You don.tneed to put water in it in a barrel it’s not water cold and you can take out the impeller because you don’t need that either so you’re not gonna hurt nothing the only reason why you need water for a game for sure because water exhaust cooled