I'm a newbie to mud motors. Just bought one of those Beavertail package boats sold by Cabela's - 1750 boat with a Kohler 27 long tail (used, 2008 model). Everything stock. Ran a shakedown cruise but came back a little disappointed.

At any speed over about 3/4 throttle, I can't keep the prop in the water. Took everything I had to keep it down. The cav plate is in fine condition, looks to be "out of the box". The prop is a bit worn down, what I believe should have been a 9" prop is now about 7 1/2". With two passengers and a dog, I got about 16mph.

Would the worn down prop cause it to pop out?

There is no way to adjust the cav plate, so I guess I would have to bolt on an extension angled up in order to get more push down. Anybody else had to do that?

Also, Beavertail recommends a 9x7 prop. I don't do alot of heavy mud, mostly just shallows but sometimes long distance so speed outweighs 4x4ing. How big could I go in order to get more speed? What are the downsides? Any advice on the best place to get a new prop?

If anyone has any ideas or advice, I would sure appreciate them.

Thx.

Bend the cavitation plate up a little and it'll ride just below the surface, it don't take a whole lot so you may want to bend it run it and then bend it to where you like it the best. The cavitation plate should be just under the surface

Cause the plate is formed (each side is downturned like maybe a flattened U), I can't see an easy way to just bend it up without permanently deforming it significantly. Will have to give some thought to attaching a separate plate, I think. Thx.

Cause the plate is formed (each side is downturned like maybe a flattened U), I can't see an easy way to just bend it up without permanently deforming it significantly. Will have to give some thought to attaching a separate plate, I think. Thx.

X2 on cavitation plate

Change the prop!

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Your Cav plate is made to be moved it will make it look different but just take a vise grips or a couple heavy channel locks and bend the cav plate up just a little. Somtimes you got a move it to get it right for your setup.

Appreciate the quick responses, all. Am heading to the water this weekend so will give it a try. Good link, LastChance.

Any advice on prop sizes or where best to buy a new one? Are the shafts a standard size for similar hp's?

I have yet to find a place for cheaper props. Right form Gd or from MB. is a good place as any to get them. I have a 23hp longtail and I had a 9x6 if you go to the websites they give ya the best prop for your motor on either site.

the motor is on a 1:1 drive, you cant put much more prop on there.

If your looking for cheapest prop, Ron Hill has the cheapest. But alot of guys don't like them. I have never owned one, so can't speak to them.
Second cheapest is Mud Buddy, I like them just fine.
Go-Devil will not let you buy one of their props because you have a Beavertail motor.
You can also get a bearvertail or Hopkins prop, but most expensive.
Looks like the size recommended for your motor is a 9X7. Best way to judge how a prop works is with a tach. Does your motor have a tach?
Does anyone know what RPM's are best for the 27 (I don't have one)?

I have mine set at 4150 OOW. I turn a 9x7 on a 1644 at about 3650-3700 by myself with a light load at 21-21.5 mph.

All the input has really helped.

Searched around and believe it or not Gander Mountain was the cheapest i could find at $200 w/ no shipping fees for a 9x7 OEM. Should have it next weekend to spin it!

Have had 4 people now tell me I need to lower the red rubber set screw. Didn't even know it was a set screw, guy I bought it from finally answered me back "Oops....should have mentioned that to you." Going to run it this afternoon and hopefully I'll just feel stupid for not having figured that out already.

Thank God for the Internet. What'd we do back in the old days?????

And no, I don't have a tach. Sounds like it would be worthwhile to have one.

On the beavertail you have to adjust the ride adjustment thats the red thing you said lower it down some when you get it set right the cavitation plate will ride just at the surface at wot.