|
| Author |
Message |
    
klatte
Visitor
| | Posted on Thursday, April 26, 2007 - 06:47 am: | 
|
hi I am trying to install a 3hp diesel with gear box in a i6 ft boat my problem is i am always out a few mm this is causing a lot of shaking the5/8 shaft was checked with the prop on and was all right from the gear box to the shaft is the problem is would u joints help? As I can not find any setup on boats with u joints. the rpm will be 1200 to 1800 max the shaft is 6ft, 3ft to the stuffing box 3ft to the prop which is brass 10inch hope some one can help me Don |
eric_schulz
Advanced Member
Username: eric_schulz
Post Number: 33
Registered: 01-2007
| | Posted on Thursday, April 26, 2007 - 07:57 am: |
|
Hi Don, I know little about boat building, but from an engineering point of view, you need some sort of flexible coupling. There are rubber jointed ones suitable for only slight misalignment, such as on an engine to pump coupling. Any transmission place that sells belts, pulleys, u joints etc, should be able to help.
Eric |
klatte
Visitor
| | Posted on Thursday, April 26, 2007 - 08:47 am: |
|
Eric I checked on flexible couplings and they wont work as my shaft has to move a inch forward and back in order to shift they will come apart . But thanks for the thought thanks Don |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 245
Registered: 07-2002
| | Posted on Thursday, April 26, 2007 - 11:22 pm: |
|
With proper alignment a u-joint shouldn't be necessary. The shaft is being supported at the engine and strut, alignment isn't too hard. Do you have a bolted flange on the engine and shaft or a slip coupling? The flange is easiest to align, you can check to see how they mate up when brought together. A single u-joint can cause vibrations, when going through rotation it accelerates and slows down, using a swivel on a socket and extension lets you experience this. When used in pairs like an auto drive shaft, one is accelerating while the other is slowing down, the shaft acellerates and slows down through a cycle, but the engine and the car don't feel it. A constant velocity u-joint like a fwd axle doesn't have this problem. |
|
|
|
|
