Fabricating an impeller?

[itstippy]

There are thousands of old, complete, small outboards for sale cheap on eBay and elsewhere - in the $20 range. Elgin, Arrow, Eska, Scott Atwater, etc. Invariably the impellers are shot and replacement parts were discontinued 30 years ago. Has anyone on this forum successfully altered a new impeller for a Johnson, Evinrude, or Mercury motor to fit one of the old outboards?
It seems like if you have the old shot impeller with a decent hub you have a good start. Take a new impeller of approximately the correct diameter, shave it down to the correct thickness, and contrive a way to fit the old hub into the new impeller. Epoxy? Fit it in and then fuse the rubber to it with a propane torch? Some other ingenious technique? Surely I'm not the first tinkerer to contemplate restoring an old outboard to useful life by fabricating an impeller. Ideas?

 

[tommays]

Re: Fabricating an impeller?

I have many rubber parts made that are NLA ect BUT it is not cheep

http://www.stilesenterprises.com/products.htm

And inpeller could be cut down and bushed BUT you wont make one from scratch without special rubber machinery

Tommays

 

[JB]

Re: Fabricating an impeller?

I vaguely remember a small outboard that I brought back to life in the 70s that had a variable displacement vane pump with spring loaded brass vanes that were worn out. I made new vanes out of brass plate.

I think that engine was a Scott Atwater or an Elgin.

I might try to manufacture that style rotor/impeller on the old hub and chrome the inside of the housing.

 

[Paul Moir]

Re: Fabricating an impeller?

Random ideas:

Always check around first. Here's one possible source:
http://www.grove.net/~noff/marx.html

Usually filled epoxy (like JB Weld) works great on rubber if its' clean. I would bet that would work just fine.

But once the rubber's been vulcanized once, you're not going to do any fusing with a propane torch.

I've often wondered about casting them out of urethane rubber or something. I kept meaning to ask petrolhead when he was around. He did that sort of thing for a living, and even cast a new propeller hub. I don't know if it would put up with the constant flexing though - I think your idea is more practical.

Another idea is to take the water pump housing and machine it to fit a current production stainless steel sleeve for a plastic housing pump. Then fit it with the unit's impeller. You would also, no doubt, have to make a bushing to adapt the modern impeller to the driveshaft. But really it wouldn't be that much work. I've been sort of thinking about doing this with a Big Twin to improve the water pump.

 

[itstippy]

Re: Fabricating an impeller?

Thanks, all.

I've been messing around experimenting with some old impellers. New ones are too pricey for experimenting with, but the old ones are hard and stiff compared to nice new rubber. So I can't fully trust my results so far. 1) Paul's observation that attempting to fuse the "replacement" hub into place with a propane torch won't work is accurate. Makes a HULLUVA stink, though, so if you ever need to create a really obnoxious odor in your shop keep that method in mind (old rubber/propane torch). I was using an impeller from a JW10 but probably any old impeller or rubberband or eraser or windshield wiper blade would work.
2) "Super Glue Gel" doesn't work either. The stuff kinda "eats" the rubber a bit and makes a sticky mess. It sticks great on fingers. It will not fuse old vulcanized rubber to old brass. I never had any luck using it on eyeglass frames either, for whatever that's worth.
3) Getting the original hub out of the impeller so you can insert the replacement hub is a laborious task. I wish I had a bigger drill press.

I will try JB Weld next. I think if I make the "doughnut hole" bigger than the replacement hub, and cut some grooves for gription, and take my time centering everything, I have a good chance of success. I will also give considerable thought to your suggestion of replacing/altering the housing to fit a new impeller instead of the other way around. Hmm.

 

[tommays]

Re: Fabricating an impeller?

it

Your NOT going to glue one that will last trust me

You stand a very good chance of takeing a different one and sanding it thinner and smaller on a belt sander useing a lot of dips in water to keep it cool

Tommays

 

[Scaaty]

Re: Fabricating an impeller?

Might what to peruse this site...they have a lot of info and parts.

http://discount-marine-parts.com/index.html

There are thousands of old, complete, small outboards for sale cheap on eBay and elsewhere - in the $20 range. Elgin, Arrow, Eska, Scott Atwater, etc. Invariably the impellers are shot and replacement parts were discontinued 30 years ago. Has anyone on this forum successfully altered a new impeller for a Johnson, Evinrude, or Mercury motor to fit one of the old outboards?
It seems like if you have the old shot impeller with a decent hub you have a good start. Take a new impeller of approximately the correct diameter, shave it down to the correct thickness, and contrive a way to fit the old hub into the new impeller. Epoxy? Fit it in and then fuse the rubber to it with a propane torch? Some other ingenious technique? Surely I'm not the first tinkerer to contemplate restoring an old outboard to useful life by fabricating an impeller. Ideas?

 

[Chinewalker]

Re: Fabricating an impeller?

As a for-instance...

I have a very nice 1952 Evinrude Fleetwin 7.5 - the one with a neutral clutch and 360-degree reverse. It uses an impeller much like those used in the 5.5/7.5 later in that decade - same impeller used in 6hp models into the late 1970s and 4hp modles into the 1980s (Sierra #18-3001). Anyway, the old Fleetwin impeller was a "shorter" impeller in profile, so I laid a new 18-3001 impeller on the beltsander and trimmed it down to fit. The motor pees like a racehorse now...

I used an OMC 10hp impeller in an old Mercury/Wizard with the impeller on the propshaft. I had to ream out the bushing and notch it to fit, but it also works well.

So, in answer to the original question, yes, there are modern impellers that are close enough to older models to work with minor mods...
- Scott

 

[freddyray21]

Re: Fabricating an impeller?

I would think finding an impellor too large and cutting it down then modifying the brass to fit what you have. The brass will modify easier than trying to glue rubber to the old brass. Or get a brass that is rather large drill a hole in it to fit the brass that came with the motor. Put the brass in the hole and fasten it with jb weld maybe

 

[steelespike]

Re: Fabricating an impeller?

I wonder if when sanding an impeller down if freezing it in dry ice would make it easier to work?

 

[itstippy]

Re: Fabricating an impeller?

Thanks guys. I've managed to make a modified impeller work on a 5HP Arrow. Slight shaving of overall thickness indeed works. Enlarging the brass hub opening works. Glue/Epoxy/JB Weld/fusing with heat/ does not work. Chinewalker's recommendation of the proper impeller to start with for a 7 1/2HP Fleetwin will help a lot. I have two of them in need of new rubber.
I also have a couple old Gale models with wobble pumps. The rubber wobble ecentrics appear in good shape but they have swelled over time and no longer "wobble" in the channel. They just go up and down in a useless pumping motion that does nothing. So, I plan to carefully remove 1/32" from both sides of the wobble "prong" to reduce it's size and make it function properly. I'll let you know the results. Does the vulcanization process permeate the entire rubber component, or does it primarily "seal" the exposed exterior? By filing down the sides of the wobble I will be removing any exterior "skin", if there is such a thing.
I bought a dozen oddball old outboards from a marina's back room and I'm having fun breathing life into them. If you start with a $20 outboard, spend 50 hours searching for NLA parts, spend $100 procuring NLA parts, spend $100 on eBay for old service manuals, and devote 100 hours of research and shop time, you will eventually prevail. You will have a good-running outboard worth at least $100! I lose money on every motor but I plan to make it up in volume.

 

[baja boss]

Re: Fabricating an impeller?

a retread plant may be able to vulcanize a old hub into a new impeller with some un-cured rubber and a hose clamp around the diameter for pressure during the curing process.i work in a plant where we cure rubber to steel forklift rims.

 

[joblo33]

Re: Fabricating an impeller?

Now that you're making these homemade impellors I think the first step on all these old motors should be to add a pisser.They may work now but best to be on the safe side.
Eric

EDIT: oops, now I see its been over a month since this thread ended..