machnumber2
Mechanical
- Feb 13, 2003
- 1
Hi,
I am making a homemade outboard motor using an old 2hp briggs & stratten 4 stroke motor. The engine rpm range is about 2000-4000 rpm.
It will transmit the power down to the prop using a simple belt-pulley system. I will need a left hand prop for this motor. The only props I can find are the Minkotoa electric motor plastic props, I bought one to install on the shaft but I do not think it will be able to handle this load.
Any thoughts about where I can find a metal left hand prop that might be suitable for this application?
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Follow Ups:
Re: Homemade outboard motor using briggs 2hp - Ken-Ohki 08:37:11 02/24/03 (3)
In Reply to: Homemade outboard motor using briggs 2hp posted by machnumber2 on February 23, 2003 at 20:56:41:
Sounds like a Interesting prodject.
Personaly, I think the minKotta prop will handle your load. You can buy thos trolling moters over 70 pounds of thrust, so I dont think you 2hp will excede that. However, You would probably get better prefromance with a standart outboard prop. As far as where to buy, any mareine store should be able to provide or at least order one for you. From your brief discription of your project, It sounds to me like your drive belt will be partialy underwater or least exposed too water. Not a great combination, but at 2 hp it might not be concern.
I am sure everyone here would love too see a picture of you creation.
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Re: Homemade outboard motor using briggs 2hp - machnumber2 09:02:38 02/24/03 (2)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by Ken-Ohki on February 24, 2003 at 08:37:11:
Cool I will continue with the plastic prop then, if it doesnt work will try a metal one. I am going to try to keep the belt pully dry by enclosing the belt in a large PVC tube and using a stuffing box on the shaft, problem is I have a 5/8" shaft and the smallest stuffing box I can find is a 3/4" and expensive. any ideas on how to make this shaft water tight using something other than a stuffing box? I will post a photo once the project gets a bit further on. Do you know where I can views pics of similar projects?
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Re: Homemade outboard motor using briggs 2hp - Ken-Ohki 14:37:56 02/24/03 (1)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by machnumber2 on February 24, 2003 at 09:02:38:
Well, I have never personaly done this. However as a avid fan of junk Yard Wars on TLC, I saw something I feel would work, Mind you this has been modifiyed a bit too the way I would do it without actualy buying the stuff you need too do it profesionaly, Like a real watertight bearing box. However..
What they did was took a box ( wooden, pvc or metal would prob work just the same ) ran the shaft through it then used like a cloth rope, looked like maybe 1/4 inch clothesline, and they coated it with very heavey grease, then wraped it in the opisite direction of the shafts rotation, ( explained it wouldnt tend to tighten and bind that way ) however, with all the grease involved, I think it might work just as well or better wound with the way the shaft turns.,) anyway, they wraped several layers,until they could fit no more wraps in the box, (wraping tight as possible ) then filled the rest of the box with heavy grease, rags and bits of rope. then sealed the top of the box. this actualy seamed to work very well and wasnt leaking water. were I too make this, I would add a few things, Cup seals on the shaft inside the box on each end to help prevent grease from slipping out or water in. I would also add a grease fitting, So I could pump grease under presure into it to make sure it was right packed as well as add more if needed later,, Presure is key here, forcing the rope against the box walls as much as possible to make a seal. I might also concider making the box dual chambered , instead of just one chamber.theres was about 6"x6"x12"
Hope this is a complete enough discription, If you want a picture of the idea, I could make you one. I love messing with stuff like this.
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Re: Homemade outboard motor using briggs 2hp - machnumber2 19:03:05 02/24/03 (0)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by Ken-Ohki on February 24, 2003 at 14:37:56:
Thats a great idea about the stuffing box, but I think what you said about the pressure being key is key also. In thier case, did they have a way to mechanically force pressure into the stuffing box, like in a real stuffing box, you can turn the nut head to increase the pressure inside. JYW's box may have worked for them and but probably leaked a few drops or more per minute. In this outboard I am making, I have no bilge to hold water, there will only be about a quart of space below the pulley so it has to be really water tight. I assume if the belt gets wet at all it will start slipping. Here are a few photos, one is of a homemade stuffing box made of copper plumbing piping, the problem is I can only turn the ends 2 or 3 turns before the threads bind up
I am making a homemade outboard motor using an old 2hp briggs & stratten 4 stroke motor. The engine rpm range is about 2000-4000 rpm.
It will transmit the power down to the prop using a simple belt-pulley system. I will need a left hand prop for this motor. The only props I can find are the Minkotoa electric motor plastic props, I bought one to install on the shaft but I do not think it will be able to handle this load.
Any thoughts about where I can find a metal left hand prop that might be suitable for this application?
--------------------------------------------------------------------------------
Follow Ups:
Re: Homemade outboard motor using briggs 2hp - Ken-Ohki 08:37:11 02/24/03 (3)
In Reply to: Homemade outboard motor using briggs 2hp posted by machnumber2 on February 23, 2003 at 20:56:41:
Sounds like a Interesting prodject.
Personaly, I think the minKotta prop will handle your load. You can buy thos trolling moters over 70 pounds of thrust, so I dont think you 2hp will excede that. However, You would probably get better prefromance with a standart outboard prop. As far as where to buy, any mareine store should be able to provide or at least order one for you. From your brief discription of your project, It sounds to me like your drive belt will be partialy underwater or least exposed too water. Not a great combination, but at 2 hp it might not be concern.
I am sure everyone here would love too see a picture of you creation.
--------------------------------------------------------------------------------
Re: Homemade outboard motor using briggs 2hp - machnumber2 09:02:38 02/24/03 (2)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by Ken-Ohki on February 24, 2003 at 08:37:11:
Cool I will continue with the plastic prop then, if it doesnt work will try a metal one. I am going to try to keep the belt pully dry by enclosing the belt in a large PVC tube and using a stuffing box on the shaft, problem is I have a 5/8" shaft and the smallest stuffing box I can find is a 3/4" and expensive. any ideas on how to make this shaft water tight using something other than a stuffing box? I will post a photo once the project gets a bit further on. Do you know where I can views pics of similar projects?
--------------------------------------------------------------------------------
Re: Homemade outboard motor using briggs 2hp - Ken-Ohki 14:37:56 02/24/03 (1)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by machnumber2 on February 24, 2003 at 09:02:38:
Well, I have never personaly done this. However as a avid fan of junk Yard Wars on TLC, I saw something I feel would work, Mind you this has been modifiyed a bit too the way I would do it without actualy buying the stuff you need too do it profesionaly, Like a real watertight bearing box. However..
What they did was took a box ( wooden, pvc or metal would prob work just the same ) ran the shaft through it then used like a cloth rope, looked like maybe 1/4 inch clothesline, and they coated it with very heavey grease, then wraped it in the opisite direction of the shafts rotation, ( explained it wouldnt tend to tighten and bind that way ) however, with all the grease involved, I think it might work just as well or better wound with the way the shaft turns.,) anyway, they wraped several layers,until they could fit no more wraps in the box, (wraping tight as possible ) then filled the rest of the box with heavy grease, rags and bits of rope. then sealed the top of the box. this actualy seamed to work very well and wasnt leaking water. were I too make this, I would add a few things, Cup seals on the shaft inside the box on each end to help prevent grease from slipping out or water in. I would also add a grease fitting, So I could pump grease under presure into it to make sure it was right packed as well as add more if needed later,, Presure is key here, forcing the rope against the box walls as much as possible to make a seal. I might also concider making the box dual chambered , instead of just one chamber.theres was about 6"x6"x12"
Hope this is a complete enough discription, If you want a picture of the idea, I could make you one. I love messing with stuff like this.
--------------------------------------------------------------------------------
Re: Homemade outboard motor using briggs 2hp - machnumber2 19:03:05 02/24/03 (0)
In Reply to: Re: Homemade outboard motor using briggs 2hp posted by Ken-Ohki on February 24, 2003 at 14:37:56:
Thats a great idea about the stuffing box, but I think what you said about the pressure being key is key also. In thier case, did they have a way to mechanically force pressure into the stuffing box, like in a real stuffing box, you can turn the nut head to increase the pressure inside. JYW's box may have worked for them and but probably leaked a few drops or more per minute. In this outboard I am making, I have no bilge to hold water, there will only be about a quart of space below the pulley so it has to be really water tight. I assume if the belt gets wet at all it will start slipping. Here are a few photos, one is of a homemade stuffing box made of copper plumbing piping, the problem is I can only turn the ends 2 or 3 turns before the threads bind up