mud motor help

[insaneduck]

Alright I got a 14 32 jon boat that I reinforced the transom on and bed lined entirely and I got a 6.5 hp longtail im putting on it with a 8" backwater prop. Its a honda gx200 motor and right now I have a new carb jet. 035 going on and a billet aluminum flywheel and rlv header and exhaust system and a k&n air intake system. Im going to take the governor out of it but my u joint is only rated for 4,000rpm n before I remove the governor it ran 3600rpm. How many rpm can I do safely in open water? Should I go bigger prop to go faster? Im also replacing the cylinder head with a gx160 and the emulsion tube with a gx140. I already got a longer spark plug to. What are some other mods to help performance in this set up? Would a centerfuge clutch be worth buying? Any input would be appreciated.

[Goldfish]

I'm not a mud motor expert (you might get better answers at mudmotorchat.com but I'm sure there are guys who know more than me here) but what I do know is that no matter what you try to do, long tails just aren't about speed. They'll get you thru hell, but you won't be the first person there. You can get farther in than others tho and that's the point.

Knowing that ratings on parts are within the safe zone and there is still some give after the rated numbers, I still wouldn't want to pass that by to far. Changing your prop to a higher speed prop is going to negate pushing power when you get into the slop and I'd rather leave 5 minutes earlier than have to unstuck a boat.

[insaneduck]

I am trying to hit 15mph as my goal. Im gonna run a tach and I was thinking maybe 4500 rpm is safe but I've been wrong before.

[3legged_lab]

Sounds like you need a bigger motor. What is your current top speed?

[Goldfish]

You just want to hit 15? When you say bedlined the entire thing, where do you mean specifically? What all else have you done to it? V-front or flat front?

[jarbo03]

4500 might be safe in bursts, I would not do it sustained.

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[insaneduck]

I want as light a motor as possible and I mean inside and out! Its sprayed on liner I did at a body shop. Flat front but im making a bracket in the shape of an A to bounce off trees. I want a light quick rig in the shallow boat lanes. Currently 8-10 mph that's stock motor no mods.

[Goldfish]

I mean is the liner on just the floor, all over the inside, inside and out, complete boat, inside, topside, outside, bottom. Basically wondering if you shot the water side causing a bunch of drag because bedliner is rought while you were thinking you were beefing up the bottom side. If anything you would want to slick up the bottom with waxes or gator glide, not try to strengthen with bedliner.

Also, 6.5hp motors aren't going to be very fast. My friend has a 37hp on his 17ft v-front tracker and don't think he hits 20. Not entirely sure about that speed, but I know that one is faster than his dad's 14 or 16ft flat front with a 20 or 25hp Honda. Both long tails and both bottoms are flat (true jon/mud boats). My 9.9 outboard on my 14' fishing boat is faster than his boat with that long tail with 3x the hp.

[insaneduck]

Everything but very bottom and its got about 5-6 coats of flat black so its slick. Guy I got it from got it up to 8mph on his boat with me in there to in a 14 36. Mines 32 bottom and im gonna turn more rpm, I know ill have a way better hole shot than before. I got a 2 mile run of deep water before I get in the woods n I wanna make that as quick as possible.

[Goldfish]

For reasons I still don't fully understand, mud boats/motors run faster in "skinny" water than in deep water. I just don't know if this motor is going to do for you what you want it to, but good luck. I'm certain guys on MMC can help you with anything more but it kind of sounds like you might be doing everything you can to it.

[insaneduck]

They can grab stuff and pull it along. Buddy has a mud buddy that was 22mph in deep water and 31mph in 2" of water a a foot of mud.

[NuffDaddy]

A 2 mile ride at 8 mph is 15 min.
A 2 mile ride at 15 mph is 8 min.
Get your ass outa bed 7 min earlier and save a bunch of money.


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[3legged_lab]

Everything but very bottom and its got about 5-6 coats of flat black so its slick. Guy I got it from got it up to 8mph on his boat with me in there to in a 14 36. Mines 32 bottom and im gonna turn more rpm, I know ill have a way better hole shot than before. I got a 2 mile run of deep water before I get in the woods n I wanna make that as quick as possible.

The speed you want may be possible, idk, you just might have to do some tinkering with gearing (the prop pitch) once you have the motor at peak power. You might be able to go to a heavier duty u-joint to cover the higher rpms. Best bet for tech questions on that size of a motor (and advice on parts) might be a kart racing forum, they do a lot of modding on small motors.

For reasons I still don't fully understand, mud boats/motors run faster in "skinny" water than in deep water. I just don't know if this motor is going to do for you what you want it to, but good luck. I'm certain guys on MMC can help you with anything more but it kind of sounds like you might be doing everything you can to it.

Goldie, think hydraulics. The bottom of the boat is pushing water down, at a certain speed the hull will "jump plane". in skinny water the downward forced water meets the bottom and gets compressed between it and the hull causing the boat to ride higher and get lift faster - less drag. In deep water (in my boat its around 24") there is no (or less) compression - more drag on the hull.

[insaneduck]

Lol I may have to! Most my parts are go kart parts I ordered from go karts usa. Anywhere near 15 ill be satisfied bc that's plenty quick for the long haul then ill have enough power to go through some rough stuff if need be. Ill shoot a video of it running some time.

[3legged_lab]

Just be happy with making it run on plane, my boat broke over at about13mph, it makes all the difference in the world to me. When I first bought my hull I put a 27 hp kawi efi on it. Empty boat - no gear, no blind, no gun box it would run 17.5 in the shallows and 16 in deep water. Once I was fully loaded I was barely popping plane in deep water, and 14 - 15 in shallow.

I have since switched to a 45 mag surface drive and love it.

[insaneduck]

Ya I just want a real light set up that I can take the motor off and drag over big levees

[insaneduck]

This is the motor not on my boat.

[NuffDaddy]

In my 1440 mod-v with a 15 hp outboard I can hit 21 with just me and no load. With 2 guys and a gear is 15. I would highly doubt you could ever see 15 MPH with your setup.


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[insaneduck]

Took it out. It hit 9 mph with two people and gear at 3600 rpm. I am gonna break it in a little bit more before I take the governor out of it. So far all I have done to it is new exhaust, new intake, new spark plug, and new carb jet. I have a new fly wheel and cylinder head sitting in my house just waiting to go on. It has lots of torque and was running through boot deep water with extreme ease and jumping logs like crazy. I am finishing up the new paint job then I will take pics of the set up and maybe shoot a video for ya'll to watch.

[Goldfish]

Did it get on plane? I honestly have no clue how fast boats go to be on plane, nor how fast my boat even goes, lol

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[insaneduck]

Right at it, it was when i took it out alone when i put all the gear on the bow but I was going alot faster to, didn't clock it. It's only a 14 32 so it don't gotta go fast.

[3legged_lab]

Like you already mentioned, do some testing with shifting weight around. Typically long tails want to dive the nose because the motor is pushing up on the top of the transom as opposed to the way an outboard or even surface drive work.
Once when I had the long tail my buddy decided to move up and sit on the front deck, that was enough to make us lose plane.

[insaneduck]

I will post a pic tomorrow of the set up.

[aunt betty]

Where the weight is in the boat matters. I found that I need my dog to sit on the bow to get going faster.
You'll be fine doing what you do ID.
I'll run my boat out ahead and grab the hole if you haul my gun and decoys. My lil 14-36 was flying through the Brake...remember when we hunted the bucket-hole?

[insaneduck]

Barrel hole n ya it was flying! Ill haul gear, I forgot to take pics again lol

[3legged_lab]

Where the weight is in the boat matters. I found that I need my dog to sit on the bow to get going faster.

Longtail or outboard? And good thinkin on the dog.

[insaneduck]

checked on a gps today n hit 12mph by myself. still gotta remove govorner and replace flywheel. ill put pics up in a bit.

[insaneduck]

In 5-6" of water, no problems. Tops out at 12 mph before messing with gov. 5 coats of oil based paint on body and inside sprayed with defender pro.

[aunt betty]

Looks good Tyler.
Make sure and leave the motor where I can use it when you're on the boat.
Maybe I should just have you build me one too.
How much you got in your motor now?

I'm thinking I'd like to try it on this. It'll bolt right on. That mount on the back is for a 5hp mud-motor.
I bet it'd go a little faster!

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