Het guys I have bent the plate above the prop like the manual stated to keep the prop just under the surface but at almost full throe and deffinitley at full throtle I still have to "pull up" on the motor a substantial amount. Which as you know would make even a short scouting trip tiresome. I have bent the plate up close to a 90 degree angle is there anything thing else I can do or another reason the prop wont stay in the water?

Are the transom heights matched?

Is the prop worn?

The prop is hardly worn and has 1 pretty good ding in it. As far as the transom height matched I am not familiar with what you are asking woodiebuster. Is there any way you can be more specific. I didnt even know there were specific transom heights needed. Its a 23hp vangaurd go devil on a 15 ft polarkraft. If that helps at all. THANX for the input.

TXHC
Is this 23 LT a new unit or used?
Measure the transom height, from the flat bottom of the boat to the top of the transom where the motor clamps on to the back of the boat. It should be about 15 to 16 inches tall.
Next look under the rear of the boat and see if the last couple feet of boat bottom is flat. It it's pushed upwards, that's called a "hook" and it can play heck with water flow off the back of the boat and how the water hits the prop.
Next, I would think your bending the cavatation plate up 90 degrees is way more than what it should be so return it back to "just a little" bend upwards. The Cav plate should be floating about 2" below the water surface when under full power with the boat moving forward. It should pop to the surface with the prop at surface level when you let off power.
Transom angle should be +/-13 degrees.
Does the motor have a rock guard? If is does take it off and see if that helps.
Hope this helps. Duckdon

Duckdon,
Thanx for the info. As far as rock guard no. I am pretty sure the height of the transom is taller than 16 inches but maybe not I will check today. I will also look into the "hook" that you explained. Now the plate is not all the way to 90 degrees but close and at full throtle the motor is to tiresome to put the plate back and when I throtle down the prop does not "pop" out of the water it actually "digs" deeper into the water. I am sure thats because od the plate bend. Any suggestions other than bend it back. I am thinking because the boat wasnt made for the motor it might be something I am going to have to put up with it but I figure someone on here has delt with this before and could help. I do appre ciate guys for any and all input. Thanx

Can you post a few good clear close up photos of the rear and rear sides of the boat. I am not familiar with PolarKraft but mud motors run best on flat bottom "jon" type boats. It ain't rocket science. Bending a cav plate is done little by little to find a "sweet spot" Sounds more and more like a transom height problem.
Is this a new motor or used? Is it a real Go Devil motor or a "home built" that we often call a Go Devil? I am wondering if the cav plate is set at the right angle to the shaft when it was built?
You can also call the Go Devil Factory and ask to talk with Warren or one of the guys about the problem if you have a Go Devil. You will need the Model # and Serial # which are located just under the U joint, on the base plate behind the motor to get past the reception desk. If the motor is older the numbers will be covered by assorted coon crap, grease and catail fuze so just scrape it off to see the numbers.
If you are new to mud motors and longtails you must understand that they do drive different than a standard outboard but that said, lots of 80 pound Korean grandma's run them all day so actual "armstrong" power is not the answer.

Yes sir I am the 2nd owner but the motor only has 25hrs on it. I am new to Mud motors but have a good buddy who has owned them for years. I am almost certain that my transom is 20 inches not 16. Its is a true go devil. The 23 hp vangaurd. I will post some pics this evening after work. The boat is a flat bottom jon boat but has the "ribs" onthe bottom. When I purchased the motor it was on a different boat And I switched to this one. The previous owner had the plate bent down which was bad on this one. I bent the plate up a little and it made it better so I bent further. I usually talk to steve @ GD but figured I would post up here first. So are you figuring it to be the transom?

Sounds like you have it figured out. In effect you put a short shaft on a long shaft transom.

What did Steve at GD have to say?
Duckdon

Long tails have been made for both a short (15-16") transom and a tall (20") transoms. They are not the same framer and your shaft might be approaching the water at too steep an angle, resulting in upward force (which pushes the handle down).

My first boat had a 20" transom and I also ran a 23hp go-devil so I had 5" deep by 20" wide cut out of the transom. It worked perfect.