Cavitation Plate: PLEASE HELP

A duck boat forum to discuss duck hunting boats, mud motors, and everything related.

Moderators: Dogman, NCSUDucker

Cavitation Plate: PLEASE HELP

Postby pettybrenden57 » Sun Mar 19, 2017 11:53 pm

I bought a KKK mud motor long tail kit from a friend for dirt cheap. The kit has a 213cc predator motor from harbor freight. There was 10 minutes of run time on it when he bought it new. But I ran into some issues. The motor will run perfect out of the water, but once the prop is in the water and runs for about 5-15 yards, it will big out and die. More the fact that that when the whole prop is in the water it happens. Here are my questions:
1. There is no cavitation plate, do I need one?
2. A couple buddies said it could be running too lean, could that be a problem?
3. Could a low oil level be an issue?
4. Would a bad bearing cause this?
5. Is the motor overheating and then shutting down?

I did join the mud motor forum but have been nothing but harassed because of the name of the long tail, so please don't bring that here. I just need help. Please and thank you! F
pettybrenden57
hunter
 
Posts: 11
Joined: Wed Oct 14, 2015 10:53 pm

Remove Advertisements

DuckHuntingChat.com
Advertisement

Re: Cavitation Plate: PLEASE HELP

Postby JuniorPre 360 » Mon Mar 20, 2017 8:10 am

pettybrenden57 wrote:I bought a KKK mud motor long tail kit from a friend for dirt cheap. The kit has a 213cc predator motor from harbor freight. There was 10 minutes of run time on it when he bought it new. But I ran into some issues. The motor will run perfect out of the water, but once the prop is in the water and runs for about 5-15 yards, it will big out and die. More the fact that that when the whole prop is in the water it happens. Here are my questions:
1. There is no cavitation plate, do I need one?
This won't solve the problem you are having. I promise!
2. A couple buddies said it could be running too lean, could that be a problem?
This is very likely if your buddy added upgrades to it and did it wrong. If you upgrade the exhaust, then it needs more air with the air intake, which you would then need to rejet the carb for more fuel. If you only do one, then there's a great chance for engine failure. Also, look into the throttle stop on the motor. Make sure to unscrew it so you can give it gas. It's the screw that stops the throttle. Also, look into cleaning the carb. But my money is on your buddy upgrading it wrong if it has upgrades. I bet you'll be buying jets for the carb. If not, just start making sure fuel lines, gas tank, and the filter is all clean.
3. Could a low oil level be an issue?
Possibly. The low oil sensor is located on the side of the motor. I believe it's a yellow wire going into the side of the block. Make sure your motor has enough oil. If you find out it is shutting off because of a bad sensor, just unplug it. I know some go karters that have done that. But I'd make that your last resort. I like having my sensor.
4. Would a bad bearing cause this?
On the motor or on the longtail kit? I'd check over everything to make sure you have some marine grease on the moving parts.
5. Is the motor overheating and then shutting down?
Again, check the oil. I've had my exhaust glowing red before after 45 minutes of running full bore. Your motor shouldn't be overheating that fast.

I did join the mud motor forum but have been nothing but harassed because of the name of the long tail, so please don't bring that here.
You'll get this a lot from someone that spent more on their motor than the vehicle that pulls it. They need to tell you that you need a $15,000 motor to look cool and kill ducks so they feel better about spending the money they did. Bragging rights and arrogance have never killed me ducks. I've done very well, knowing the limitations of my boat and motor, and it has served me well. Cost me just under $1,400 for the new motor and boat. The mailman also asked what I had ordered from the KKK :lol3:
I just need help. Please and thank you! F


Feel free to come on back and I'll help as much as I can with my limited knowledge. Another place to look is the OMB Warehouse forums. They are all Predator Motor gear heads. They're the best when it comes to these cheap motors.
A BAD DAY AT THE MARSH BEATS A GOOD DAY AT WORK.
User avatar
JuniorPre 360
hunter
 
Posts: 3567
Joined: Sun May 15, 2011 12:40 pm
Location: Canal de Panama

Re: Cavitation Plate: PLEASE HELP

Postby Bluesky2012 » Mon Mar 20, 2017 10:51 am

I'd agree with the idea that it's a fuel issue. When it's dry, it doesn't take a lot to spin the prop, put it in the water and it bogs down and dies. Could be dirty carb, carb is set wrong, fuel line, etc. Hard to diagnose over the internet, but id confidently bet it is in fact a fuel/air related issue.


Sent from my iPhone using Tapatalk
User avatar
Bluesky2012
hunter
 
Posts: 2475
Joined: Sat Aug 11, 2012 12:14 pm
Location: up the creek without a paddle

Re: Cavitation Plate: PLEASE HELP

Postby Darryle » Mon Mar 20, 2017 1:52 pm

How smooth does it run out of the water, surging, stumbling rough idle?

I am going to go with the oil level sensor, you can add a little more oil and see if that eliminates the problem, if not, I am going with gummy carb. A new Honda clone carb is stupid cheap to futz with cleaning it out and taking a chance of not getting all the passage ways clean.
NRA Life Member
GOA Life Member
NSCA Life Member 646442
User avatar
Darryle
Orphanedcowboy
 
Posts: 2321
Joined: Sun Feb 27, 2005 10:39 am
Location: Ft. Worth, Texas

Re: Cavitation Plate: PLEASE HELP

Postby mudpack » Mon Mar 20, 2017 2:06 pm

Bluesky2012 wrote:I'd agree with the idea that it's a fuel issue. When it's dry, it doesn't take a lot to spin the prop, put it in the water and it bogs down and dies. Could be dirty carb, carb is set wrong, fuel line, etc. Hard to diagnose over the internet, but id confidently bet it is in fact a fuel/air related issue.

Blue is on the right track. Sounds like a plugged high speed/main jet. Have the carb cleaned.

This first time my Honda-engined Mud Buddy died out in big waves because the oil level sensor thought it was low on oil, I unplugged it. I check the oil level several times a season, so low oil is never an issue anyway. In my opinion, that feature is for people who shouldn't be running a mud motor anyway.
Often wrong, never in doubt...
mudpack
hunter
 
Posts: 9626
Joined: Mon Feb 23, 2009 10:40 am
Location: Central Kansas

Re: Cavitation Plate: PLEASE HELP

Postby shoveler_shooter » Tue Mar 21, 2017 6:58 pm

Bluesky2012 wrote:I'd agree with the idea that it's a fuel issue. When it's dry, it doesn't take a lot to spin the prop, put it in the water and it bogs down and dies. Could be dirty carb, carb is set wrong, fuel line, etc. Hard to diagnose over the internet, but id confidently bet it is in fact a fuel/air related issue.


Sent from my iPhone using Tapatalk

My force outboard had the same problem. There were actually multiple issues but I worked through it eventually. A gasket was broken and had a gap in it in the carb. Rebuilt it. Float was set too open, manufacturer specs were actually wrong. Fuel pump was also going bad and one day it completely blew. I also replaced all fuel hoses and fittings, and the gas tank. Finally, the manufacturer specs were also wrong for the fuel/air mixture screw on the carb and I had to play around with it until I figured out where it ran best.
It would run perfect and you could not get it to die on the water hose in the driveway. Once you took it to the lake, it would magically not run very well at all.
User avatar
shoveler_shooter
hunter
 
Posts: 4969
Joined: Sun Nov 19, 2006 8:27 pm

Re: Cavitation Plate: PLEASE HELP

Postby Sandor27 » Wed Mar 22, 2017 7:09 am

What size prop is on it? The stock 6hp works well with 6 or 6 1/2 thai props. If you go larger it will bog.
User avatar
Sandor27
hunter
 
Posts: 141
Joined: Thu Sep 22, 2011 8:54 am
Location: Port Penn, DE


Return to Waterfowl Boats, Motors, & Boat Blinds

Who is online

Users browsing this forum: No registered users and 9 guests