• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

How far to lower rear of engine?

Root Pass

Root Pass

Well-known member
Will lowering the rear of my engine 3/8 of an inch make any noticeable difference? My 16' Freedom Craft does not porpoise at all, ever, and feels as though the nose is plowing when running dry. I can lower the rear 3/8 by just removing a spacer and not having to modify the stand,but if,as a general rule, it needs to be more that 3/8 I'll have to try something different. I know each case is different but just looking for some opinions.
 
Actually to get it off the nose raise the rear of the motor up,,, lowering the motor will make it ride on the nose more!
 
What a difference a 1/2 inch makes. Who wouldn't want another 1/2 inch!?! :wink:
Thanks for the advice.I would try a little more but I am worried about clearance with the prop and cage.
 
It's cool when a little change makes a big difference that means your boat is close and doesn't have any major problems. It's opposite of what most people think but raising the rear of the motor raises the nose. Because the prop seeks level.
 
COOL DEAL ! THE PROBLEM IS WITH THE NOSE IT BENTS DOWN ! IT LOOKS LIKE IT HEAVY! BUT NOT AS MUCH AS YOU THINK ! JUST THE WAY IT IS MADE ! GOOD DEAL YOU HAPPY, I AM HAPPY ! I GOT A KENNEDY 16 SAME DEAL, JUST A LITTLE HEAVIER ! AND YOU STAY DRY IN 3 FT CHOP IN THE BAY ! AND IT RUNS THE HILL VERY WELL! IT LIFT THE BACK UP A LITTLE ON START ! BUT JUST HAPPY TO BURN SOME FOSSILS ! WILL TWEET IT LATER ! :D ( NO STITCH'S OR BLEEDING AT THE PRESENT TIME) :D
 
Since Waterthunder provided the leveling solution, maybe he can tell us which is the front and which is the rear of the motor. I deal mostly with airplanes so the front of the motor has a propeller on the front end of it. Now car motors usually have a radiator in the front of the motor and the flywheel and flex plate at the rear of the the engine.

Now is the front of the motor near the transom or near the bow? No wonder they came up with nautical terms.
 
There are tractor airplanes and pusher airplanes. Over the years there have been tractor airboats as well but now most are pushers. In "CONTEXT" the rear for most airboat discussions is the prop end because the prop end is the end at the rear of the boat.

I think if you still have a tractor type airboat you are likely to call the prop end the front of the engine.

When it comes to symantics I get hung up on calling an engine a motor. Swapping at will these terms has led to bastardization. Initially an engine was a fuel powered source and a motor was powered by electricity. Hence the motorcar was initially used to describe only electric cars. Look at ford for a prime example...... FOMOCO but they are engine powered. To my knowledge Ford's origonal cars were NOT electric either. Dilution of meaning. Today they appear to be interchangable terms. Sad but true.

Scotty
 
Southern Airboat.com my have finally discussed everything now!!The prop is at the back of the boat.It's the rear.It would still be the rear if it was in a car with the transmission on it. Or am I wrong...
 
I think the rear of the engine is where they take the drive from. If you had a tractor
dd sbc the rear of the engine would still be at the prop! :lol:
 
Des Moines what's your question? Is it which part of the motor are they adjusting to raise or lower the nose of the boat? They are adjusting at the rear most engine mount in the boat.

Des Moines you know aircraft right?
How are engines referenced in a pusher application?
How are they referenced when its mounted in a helicopter?

How about when an experimental has an auto conversion with a drive unit?

The centrifugal force of the prop will cause the the engine to find "level".
If the engine is not in the "sweet spot" an airboat might hop or porpoise or want to plow or push the nose down. It is easiest to make this adjustment at the propped end of the engine or rear when it's in an airboat.
 
Yeah as far as AC/Auto. It is probably the manufacture that determines the front/rear. The front of an old saab faces the rear of the car, transverse front is usually where the accessories are. Airplane engine the prop. I don't know how Porsche does it,
 
if a tree falls in the forest and no one is there to hear it does it make a sound? who cares just adjust it as needed to level out the boat to run like you want it to run.
 
He$$ cntry I could stand under a falling tree and not here as deaf as am I love airboat noise :D


You were a rocket scientist right! :p
 
You must log in or register to reply here.
Back
Top