Well, after reading the post and links in OUTBOARD JET HELP I decided to get off my butt after work tonight and work on the boat.

I started the project by taking the pump off my outboard and removing the impeller. I was amazed how rounded and dull the leading edges on the impeller were. The grates were a little bruised as well.



The first objective was to cut a sharp edge on the leading blade of the impeller. I set the impeller up on a mill. One thing that surprised me was the inconsistent heights of the blades. One blade was doing the grunt of the pulling.



After about an 90 minutes I now have an impeller that should cut water with little resistance.



The next step was turning the grates into a tear shape. I cut a radius on the leading edge and brought the trailing edge to a point with a 20 degree angle.





Here's a pic of the finished parts.



Tomorrow I will shim the impeller, assemble the grate parts, put new plugs in it and try her out. I hope the project improves my fuel economy. I don't know how many more $35 dollar days (gas only) of fishing I can handle.

LT

LT
You shouldn't have put up pic's of this, now every one will want you to do there's.

I made the same mistake before.

I should of said I was a machinist to.

Nice job, Lunchtime!

You're invited (your metal-working paraphernalia as well) when I take mine apart!

here is a link for a how to from outboard jets:

http://www.outboardjets.com/IMPELLER%20SHARPENING.pdf

LT, I'm totally jealous that you have those tools! Great Job!

I have a buddy who's a machinist, I'm sure if he could he would delete this post before I could see it!
I am really interested to know of your performance observations once this is complete!!

Homer - I don't mind helping others out. The major time in the project was making the arbor. The actual machining of the impeller was about 10 min.

Fish Doc - Thanks, I have some tips if you need them.

rwgav8 - Nice link, thanks, it was reassuring to see that my intuition on the leading edge angle was correct.

jimh - I wish they were my machines, I just have a great employer that allows free reign of the shop after hours.

escapee - I know how your buddy feels.

The project is a day behind. Yesterday I decided to polish my impeller. After three hours it shines like a mirror. I couldn't bear the thought of putting all this time into the job and have an impeller with a rough cast finish.

Tonight after work I'll dunk her. I will post pics of the impeller and the lower end re-assembled. escapee - I'll let you in on the performance improvement (I hope) in a few days.

Heres a pic of the impeller after I polished it.



The results of the project are: Top speed before 22 mph, after 38 mph. Fuel consumption cut by at least a 1/3. The eight hour project was more than worth the time.

LT

Very nice!

Thanks Homer.

WOW! Way to go.

Lunch Time,

Are my eyes deceiving me?

Are the intake grates only beveled on the back sides?

Shouldn't they also be beveled on the front edge!

Nice job, it looks very good.

fp

fp - the leading edge of the grates are a full .070 radius the trailing edge come to a sharp point. Its not an airfoil (hydro either) but the shape is similar to an airplane wing.

LT

I wonder how big was the smile on your face when you opened up the throttle that first time? How exactly does one polish stainless like that? (I'm taking my pump apart right now waiting for a reply!)

escapee - I started grinning again when I went to the pump.

Polishing stainless - I knocked all the high spots off with a file. Then I started with emry cloth - 240, then went to silicone carbide wet/dry 320, 400, 600, 1500(not necessary). I used lots of WD-40 - keeps the paper sharp longer. Every time I changed grit I cleaned the impeller with simple green and hot water. For the real pitted area I used a dremel with some rubber abrassive wheels. They are actually called MX wheels and I order them from a company out of California called Artco.

Did your buddy machine the leading edge?

LT

No, I just sharpened it with a file, I know it's not as good, especially the part about making all of the edges of equal height. I think I have asked for too many favors from him lately to bring in my impeller, I will have to wait on that one for a while. How did you address balancing the impeller?

escapee - The impellers come balanced from the factory. The amount of material removed (small quantity) when machining the leading edges is insignificant to the balance. I'd be willing to say that it runs more true now. The sound improvement tells me that.

LT

LT,

I heard you got a piggy yesterday...how much do you think it weighed?

Thanks for the boat ride on Friday...

Everyone, I've been on LT's boat both before and after the pump remodel, and it's a lot faster and quieter...the motor doesn't sound like it is straining as much to get the boat up on plane and running at top speed.

Fish on...

Todd

escapee - Check your Email.

Todd - 47" ling, I don't know how much it weighed. If I had to guess I'd say about 45 lbs. I don't have any pictures. DJ took one from his boat, maybe I can get him to post it.

LT