I have a few of them for backups. The guy I bought the boat from had a bunch of extra impellers and a few housings. I've always done the entire kit since it all comes off anyway. This has been something I've wondered because I have heard a few people talking about just doing the impeller.

Plastic pump? Do the whole assembly/pump.
Brass or stainless? Just the impeller unless worn or has trouble priming/pumping.

,Steve check out SS housings and impeller kit from Harden marine, very easy to install, Dave at MDG has my motors on the Dyno, go check out the harden housings. [ATTACH=CONFIG]554771[/ATTACH]

Do the dry run impellers really work? It seems like that with a SS housing would be nearly indestructible.

That Hardin Marine SS housing looks like a great idea, tho I have never had a plastic one give me trouble.. Change impeller more regularly and housing now and then.

I think it probably depends how much silt is in the water, and pulling up to sand bars and such. I changed my impeller last year and figured on the housing but it looked new after 2 years so I left it . Don't forget the oil change if fuel pump combo.

Could you or somebody expand on that answer. Oil change in fuel pump combo? Heard of this but never touched it...What do I need to do?

Where did you get the formed water hoses?

If your mechanical fuel pump bolts to your block disregard, but if your mech pump bolts to your impeller housing then follow along-

Unhook the lines from the mech pump and then unbolt it from the impeller housing. In that cavity there is the impeller shaft and on it the cam lobe that actuates the fuel pump foot. This cavity should be filled with merc gear lube, but in some gases gasoline can leak from the mech pump and dilute the oil. This will ultimately result in failure of the fuel pump to do it's job properly. So whenever you pull your impeller you should pull off the fuel pump. pull out the old oil with a syringe or similar and refill with gear lube.

Attached is a pic of my fuel pump after I lost a seal and evacuated the gear oil to my bilge via the v-belts. Different cause, same end result. Please note wear on the pump's foot.
http://i1151.photobucket.com/albums/...ps1211ef80.jpg

There merc 500 efi hoses.