Why don't they make stainless steel impellers?

[ryanerb]

Re: Why don't they make stainless steel impellers?

Howdy,


There's also the problem with sand and debris or other injestion FOD (foreign object damage) mentioned above.....



Regards,



Rick

Ya, I think a strainer would be a must. I know some guys put strainers on the PWC's when riding near the beach in the ocean to catch some of the sand. Despite FIP allowing some debris, I would think moss/sand/ etc going through the cooling ports/system on the boat is definitely NOT a good thing. Surprised it works as good as it does. It would be fun to put a strainer on and just see how much it catches. Problem is, like i said, you gotta watch that strainer like a hawk to avoid clogs!

Ryan

 

[HT32BSX115]

Re: Why don't they make stainless steel impellers?

Yeah. A "Sea-Strainer" would probably be a source of overheats too if allowed to plug up.

Most stern drives have small holes in the water pick-up so they only let small "stuff" through.

I bought a strainer off ebay some time ago thinking I would install it, but I just bagged the whole idea altogether. It's just not necessary in fresh water under most circumstances.

Before I installed my 454 a few years ago, I popped all the core-plugs in the block and removed a LOT of sand from the water-jacket.

The (125hr since new) engine was used in a boat that never saw salt water!

I would LOVE to try one of those blue impellers.....but I would want to hear from more than a few people that have "had no problems with them' before I tried it.....


It's hard to beat the OEM stuff!!


Cheers,


Rick

 

[JimS123]

Re: Why don't they make stainless steel impellers?

And just how much do those positive displacement pumps cost? I suspect by the time they would get "marinized" to handle the sand, silt, and muck, and other debris that passes through them the cost of the outboard would go up another couple hundred bucks -- if one is lucky.

I've never seen them as small as what would be in an outboard, but based on the cost differential among various sizes I would guess it would be in the $500 range. "Marinizing" would be a downgrade. I've pumped concrete, slurried sand and highly abrasve minerals on a continuous basis. A little sandy water would be a cakewalk....LOL.

I'd gladly pay $200 extra for any outboard to have a lifetime impeller.

 

[Don S]

Re: Why don't they make stainless steel impellers?

I'd gladly pay $200 extra for any outboard to have a lifetime impeller.

You are kidding, right? Do you think all these other pumps are maintenance free? If so, think again. They probably cost more initially, and require more frequent repair.
There is nothing built by man that doesn't require maintenance or occasional replacment. Especially rotating, pressure devises in dirty water.....................

 

[JimS123]

Re: Why don't they make stainless steel impellers?

You are kidding, right? Do you think all these other pumps are maintenance free? If so, think again. They probably cost more initially, and require more frequent repair.
There is nothing built by man that doesn't require maintenance or occasional replacment. Especially rotating, pressure devises in dirty water.....................

Oh for sure, nothing is maintenance free. As an Engineer I look for low mantenance items.

Put a pressure gauge on her fore and aft and monitor the change. Then tear her down when the PM calls for it. My point was in reply to the OP that mentioned SS. If an industrial pump in a harsh environment can last 10 years of continuous running (BTW that's 87,600 hours) then she'll laugh at a little salty sandy river water, which in the same terms is a pretty easy environment.

 

[Scott Danforth]

Re: Why don't they make stainless steel impellers?

You are kidding, right? Do you think all these other pumps are maintenance free? If so, think again. They probably cost more initially, and require more frequent repair.
There is nothing built by man that doesn't require maintenance or occasional replacment. Especially rotating, pressure devises in dirty water.....................

Don, you are correct there. Anything man made will fail.

the issue with raw water pumps is that us boaters usually use sand to polish the inside of the pump, suck up biologicals, etc. Having worked in the marine heat exchanger market for a while, you would be amazed as some of the fouling that has been encountered.

Here is the long and short of it with all raw water pumps:
They need to be self priming
They need to flow 20gpm or more
they need to provide 20psi or more
the need to have a vertical lift of 4 ft of water or more on the intake side
they need to be cheep
they need to be able to be assembled by workers with minimal training, minimal technical ability, and minimal mechanical experience (the cashier at walmart that just got the job assembling pumps)
they need to be serviced at a minimum once every 2-3 years or less to clean out the crud and check the system over (planned maintenance thru planned part obsolescence)

the pump housings on outdrives and outboards wear out as well, so replacing the impeller leads to replacing the pump usually.