Hey guys,

I need some help, I am a recent new owner of a 25hp Kohler Lontail MM, that is running a Lowe 1652 Roughneck. I recently modified the cavitation plate for a HT boat and need some help on the proper way to set the prop depth for running in water/mud.(the adjustment bolt on the transom mount)

I took it out this past weekend and fought the motor from going to deep into the mud and think that if I get it adjusted right the stop will keep me from having to fight it. What is the proper way to adjust this or set it up so it runs in the water at the correct depth for the best movement and performance.

Any help or ideas would be greatly appreciated.

Thanks

mines adjusted to where it runs bout a 1 inch to 1 and a half under the water and it runs fines when i get in shallow water runs awesome hope that helps man

So you can't adjust the cavitation plate to keep it from going too deep?

The motor is supposed to "float" while you run. It will be where it needs to be while planed off unless your cav plate is bent the wrong way or something causing it to dig.

Warren Coco at go devil told me that there are two types of longtails that they build the standard model that is for a short transom boat 15-17in and a HT model that is for a tall transom boat 18-22in. I had to cut off the old cavitation plate and weld the HT one onto my motor for my tall transom boat. They are angled different to keep the prop down in the water and not fight it, well now I am having to fight it the other direction.

Did you try bending the back tab of the cavitation plate down?

The bolt you mentioned should only be used to keep the
motor from dragging the ground while trailering....

I was told by my GD man that if you try to extend it or
run the motor touching it - you risk bending or breaking
the shaft.... Way to much leverage that close to a pivot
point / leverage point....

You gotta get control by adjusting the cavitaion plate and
trailing edge fin...

post some pics - from behind - where cav is parallel with
the bottom of the boat - no matter where that is....

As far as the adjustment bolt, in your first post, All that does is adjust prop depth in mud. There isnt much use in letting your motor go too deep cause in some situations you wont be able to get it back out of the mud. Or youll break your handle off trying. I had mine set where when my boat was on the trailer, my cav. plate was about 4 or 5 inches below the bottom of my boat. Now I had the 72" model on a short transom. I never had to fight it in mud as far as diggin too deep is concerned. About your cav plate modifying, I dont know man. Somethin dont sound right fo sho.

As far as the leverage theory goes.... Ive been stuck and actually picked the back of my boat up with the prop end of the motor and turned around like a big azz paddle and didnt break anything. I know its not good but when the going gets tough..............

I left the trailing fin straight just as it was sent to me by GD, it about killed me this weekend to fight it while trying to get back to the ramp, not to mention the previous owner had the govener spring in the wrong hole causing me to loose 500rpm's. I need to figure this out my arms are sore lol.

Keeping the prop in the water is not the issue, my motor wants to dig a hole just keep going straight down, I almost had to have all my weight on it just to keep it up and going. We were running shallow water abotu 18-20in deep

here is a pic of mine!

Shiat couple years? I learned dat chit fast, soon as I buried dat biatch 3ft down.

That bolt can't be that damn important cause my newer model doesn't have one. But on this one I do have the swivel.

Believe me the surface drive is in the future, need a couple seasons on the stick first though. I think it will do me fine if I can ever get it adjusted out right.

Think of a 25 HP - auger - you are not strong enough to keep that
thing from diggin a hole to China - IF you let it screw down into the
mud too much....

Even a properly setup GDLT can give you a heck of a workout if
your technique is wrong.... At very slow speeds the prop is in
your control - not really affected by the cav plate much at all....

My first trip with a bigger LT - it whooped my butt... Then learned
not to let that screw have too big a bite of harder mud --- that makes
all the difference in the world.... Think - auger - don't let it get
screwed in too deep - before you "blow it out" and go back down
for another good bite....

In a serious "attack mode" the cav plate will be three inches above the water anyway and the prop in a "surfacing mode" --- with no more
than about 2000 rpm or less....

Personally, I know the bolt adjust probably would help but there are some cases in which you wish you had more depth. I went over a 2' deadfall with two buddies of mine last hunting season thinking the tree would go down. Hell no. Drove the boat halfway over that biatch, had to make them get to the front to make the boat break over, then my azz was too high in the air to grab any water. Took a lil while to get over it but we got it. Now if that deadfall was a lil shorter no prob, but with a bolt stop I wouldn't have a fighting chance. I would try adjusting the cavitation plate down on the back and put some more stick time into it before messing with the bolt.

Nah man, I didn't mean go out and buy a surface drive. I meant exactly what Giga said.

So the general concensus is I should try to bend the tip of the Cavitation plate DOWN to help the prop ride UP and not dig as much.

And when running keep the prop 3 inches or so below the water and go from there?

Please correct me if I am wrong or any other suggestions would be greatly appreciated.

Bend the azz end of the cav plate down, 1/8" at a time until the plate rides a bout 1' to 1 1/2" below the waters surface.

No

You need to learn a trick - "surfacing" the prop - where your cav plate
is sticking up in the air 3 inches ABOVE the water....

Set the BOLT - to ONLY keep your motor from draggin ground while
trailering.... Like KIBB said - you need depth sometimes to jump logs...

Take a pic from the back - of your cav plate level / parallel with the
ground / bottom of the boat ---- then get some more input regarding
the cav plate final adjustments....

It would probly whooped you even setup perfect --- mine whooped me...

Then I wised up on "finesse not muscle"....

Is the surfacing the prop only when you are up to speed attempting to float across the water or do you surface the prop even in shallow water, just going down the boat lane to a shooting spot?

I will try to post pics tomorrow.

In the thick chit. Soup.

Hmm, I guess I have got alot of learning to do, along with my other problems.

Boat not drafting well
Too Damn Heavy.
Not enough speed(think I got that fixed with the rpms though)

Needless to say thanks to your guys help, I will get it figured out.