So I just finished up my Mad mud motor. Took it out to test it out. Starts good, runs good but as soon as I drop the cav plate under the waterline the motor shuts off. I used a Honda gx200 6.5 HP. I have a 7X4 prop on it. It was just me (250lbs) in a 10 ft jon. Cav plate is set at 1/2" above the top of the prop per Mad plans. It seems to me that I need more torque and power or a smaller prop. Am I wrong?

What are you RPMs at idle out the water? And why is the cavitation plate bent down?

I don't have a good answer why I bent down the back of the plate other than, the plans said to do so. Don't have a tach, but no matter where I have the throttle it does the same thing. I don't have a squeeze throttle setup yet so I am just using the oem lever that holds it position where you put it.

So it kills like u shut it off or dies from bogging down

If it dies like u shut it off, check your oil level, the low oil sensor may be shutting it off when the motor tilts back to put prop in water

Yea it dies from bogging down. Soon as it goes under load it shuts off. I will test it in the morning leaning it back with no water, but I highly doubt thats it, because it is very close to level when in the water.

Your plate should be level...... Once you test run you should have to bend it up where it rides right under the surface.

The plate wouldn't cause the issue u are having tho, sounds like your governor is not speeding the motor up to compensate for the load

Does the motor wind up more by pushing on the governor linkage?

10-4 on the plate. I haven't removed the governor, which I know I probably need to. Yes when I pull on the linkage I can override the governor. Haven't tried that in the water though. The shaft spins freely. Not so much that if i remove it from the u joint it wil just continually spin with a flick of the wrist, but I would still call it effortless. Minimal resistance.

i had this problem with my 16 hp longtail. i know this probably isnt the case with yours, but it turned out to be a bad coil. just another idea incase nothing else helps

So it turns out it was the low oil sensor after all. I unplugged it and it worked great. I just happens to be at the same point as the cav plate being fully submerged. How far back can you lean the motor before it becomes unsafe? I changed the oil and filled it to the max level. I think I'm fine, just curious.

I think 35 to 45 degrees

Ill send you a bill

Haha.. Thanks bud