496 HO Impeller Change
 

Can anyone give me the quick over view for changing the raw water impellers on a 496? I have 2006's with the gen 2 cool fuel units.

How many bolts, clamps, hoses, accessories need to be removed to pull them. This is on twins so space is at a premium.

Thanks in advance!

Techman.

If possiple remove the pumps and replace the impellers on the bench. 2 large hoses and clamps to remove from the back and a small hose (if you have a water pressure gauge) on the side of the pump. It might be easer to cut the small hose if it fights you...We had several inches of slack on ours so it wasen't a problem. 2 bolts in the front of the engine hold the water pump bracket on.

Make sure to note which hose comes off which port on the back of the pump...it is very easy to reverse these which would cause lots of damage

Any trick to loosening the serpentine belt?

Since I am missing an engine (compared to most of you) I keep an extra pump on board. Let the tensioner off, loosen clamps, remove the (2) 10mm bolts and its out. Slap the other pump in replace impellor later for the spare.

There is a tension/adjustment bolt on the other side of the engine.

Just did this on Saturday....
After removing the serpentine there are the two "nuts" that are on studs and an upper bolt that holds an idler pulley that must come off.
Once these are removed you can remove the sensor connector and the two hoses. The hoses turned out to be the nightmare of the deal with my limited space :(
Once it's out, note the direction of the fins and replace the impeller. (We ended up using a zip tie to colapse the new impeller and it went in pretty easy)
Add a little Dawn into the housing, replace o-ring, re-assemble and re-install.

Have fun!!!!

Dave

Does the idler pulley come off or just the bolt that you describing? Also, are the nuts on studs on the front or back?

Yes, but it is very easy.
It actually mounts over the studs and over the sea pump bracket so it has to come off.
No worrys though, that's the easy part.

Dave

Sorry, Front

Thanks! Not a lot of room down there so I imagine a few scraped nuckles!

Oh Yea!!!
(fricken hoses!! Thanks to DesertMirage here on the boards for coming by to help :ernaehrung004:)

Less time fix'in more time boat'in!
 

If you guys are going to have to replace the impellors or pump on the 496's check into using the stainless end plate kits and impellor kits from R&R guys in Lake Havasu, they definitly got a great little kit to save those expensive pump replacements. Also I know the builders hate to up the price of that boat with a strainer, but for gods sake if you boat in a debris water (regular strainer)area or around sandy bottoms (sand strainer), get one !!!!!
don't fight it, STRAIN IT!!

Best Regards,
Ray @ Raylar

Ray,

I do run a sea strainer and I've been pretty good about staying out of the sand, etc. Is it a good idea to order the replacement backing plates before I dig in from R&R? I am assuming that I only need to do the impeller. (2 seasons at 100 hours). Perhaps I should hedge my bet and just do it all at once regardless of the original pump condition?

Wish I'd known about those last week!!

By the way, I was living on borrowed time at 280 hrs on the originals :crazy: (housing looked great though)

Thanks for the info Ray...

Dave

When I was tearing mine down every winter,500efi's 50 hours and iam real careful on the shallow water and sand bars,you wouldn't believe the sand in the bottom of the water jackets:(

I never get anything in the sea stariners, I bet a sand strainer would catch alot!!