Some impellers are built with threads in the center. It is a step larger than the bolt that came out of the crank. This is the best case for removal. You buy a longer/ larger bolt that threads into the impeller and it puts pressure against the crankshaft. It will either release or may need a whack. You may be able to hydraulically remove it in this way too.I'm unsure if all of these used that design w/ the tapered shaft. Be sure to look for set screws, but they aren't used on tapered crank models. I've had straight/ keyed cranks on some. Some have threaded holes that can be used to push from the crank. Certain ones have nothing at all to help.

The impeller looks very similar to my Troy Bilt (MTD).
I was able to borrow a large wheel puller. I used a sacrificial bolt in place of the bolt that holds the impeller, so as to not damage the shaft. You should be able to rent one from a tool rental store. The wheel puller has to be large enough to reach the outer edge of the impeller.
There will be a loud bang, and I mean LOUD when the impeller breaks loose from the shaft. When you are done tightening the shroud bolts, you just have to put the impeller back and tighten the bolt back down.
I had to replace my impeller about two years ago and have not had any problems with it since.
The issue I had with mine was the way the flails were secured to the impeller, the pins through the flails were held in with roll pins which were covered with a spring clip. The spring clip was not aggressive enough to withstand the rotational forces during operation. The spring pins flew off, the roll pins backed out, the big pin also backed out and the flails came loose and then self destructed the impeller. This happened twice, MTD finally redesigned the impeller assembly using locking bolts instead of pins. As I said I replaced the impeller two years ago and haven't had an issue. Anyway, my point is while you have it apart make sure that the flails are held in with locking bolts instead of pins.
Hope this helps.

Tomplum,
It worked like a charm. I did not realize it came off like a generator. I started to use a puller and got nowhere.

I finally got the impeller loose on my MTD in order to replace missing bolts and to sharpen the blades. Use a "sacrificial" bolt, drill in the center of the head of this bolt so that your wheel puller won't slip. Be sure to thread in the bolt leaving about an 1/8 gap. I used an impact wrench to bring up the tension. During the night we heard a "bang". The impeller was loose. No key, no set screws. Don't be tempted to use the larger thread on the impeller to push against the motor shaft. You may damage the threads of the motor shaft.

AND . . . Don't forget to slop on the
anti-seize when you put it back together.

Duplicate post

This post was edited by renelson177 on Sun, Nov 2, 14 at 14:12

I hope this response to an old thread helps someone. A puller is not needed to remove the impeller. You can make your own impeller removal tool for about $1 or buy one for ~$20. Here's the link to a youtube video explaining how to make a tool and how easily the impeller comes off. http://bit.ly/2EnY27x

IMPELLER REMOVAL TOOL and PROCEDURE