Newer style raw water pump? - Maxum Boat Owners Club

bobgaudette · 07-23-2017, 03:43 AM

Quick background. two mercruiser 4.3 with bravo 2's. one 2004, one 2007. The 2004 one has the raw water pump that you can take the whole back of the pump off and replace it and the impeller. Easy enough. The 2007 is completely different. It has much shorter screws and the "back" side has just the in/out hose connections. Looks like the impeller must be in the side with the pulley. My question is do you need to take the whole pump off the motor to fix it? And can it be fixed, aka replace the impeller, or do you need to replace the whole pump? It was $65 to fix the old one. Is it gonna cost $375 to fix the new one, aka replace the pump???

mmwjr · 07-23-2017, 04:09 AM

I'm not fimilar with what you are saying the 2007 is like but it sounds like you remove the rear cap that has the two hose connections to access the impeller and can then just pull it out to replace for $35. My 97' is like your 2004 and I only replace the impeller and not the pump housing.

bobgaudette · 07-23-2017, 11:15 AM

I would agree with you Mike, but there are two issues. First, if your looking at the pump from the hose side, the top right hand corner has a screw hole that lines up with a bracket on motor. I can see a screw/pin in the hole but it has no head. not sure if its a pin (dont think so as I can see threads) or if someone broke off the head of the screw. Second, if you take the cap off with the hoses (I cant yet because of the broken screw/pin) and find the housing scored, do you have to replace the whole pump as your only removing a cap to get the impeller out?

mmwjr · 07-23-2017, 12:42 PM

Does this pump have two drain plugs? If so I believe it is a brass housing and has a replaceable internals if scorn.

Guess you'll just need to remove it and see what you have.

bobgaudette · 07-23-2017, 02:19 PM

Yes, it has 2 drain plugs. You wouldn't know part numbers for the impeller or internals replacement??

dave4boats · 07-24-2017, 01:01 AM

One pump is a two piece housing the other a one piece. You can replace just impeller on both. It's not that hard to remove whole pump to replace impeller. That's how I do mine. I also keep an extra impeller kit on board and have done this in water at the docks. Just make sure you keep water inlet hose above water line or else water will fill your bilge up.

mmwjr · 07-24-2017, 01:39 AM

There are more than the two styles, the initial design is known as the two piece which was latter replaced by the one piece housing. However latter version added two blue drain plugs.

To my knowledge they all use the same impeller.

BTY the old 7.4 used a special pump that had a provision for the mechanical fuel pump.

speedysprocket · 07-24-2017, 03:26 AM

Should be easier to take the pump off to rebuild than trying to do it while still on the engine. Even easier because you don't have to worry about he mechanical fuel pump that is part of the older water pumps!

bobgaudette · 07-24-2017, 04:34 PM

I knew water would come in as when I removed the two plugs I got water so when I took hose off I raised it up. Any thoughts on the broken screw? It's the top right looking from the hose side. I can't get pump off because of it. I might try getting a hack saw blade in there to cut it off so I can at least get the back plate off and see if I can remove the screw end once it's out.

mmwjr · 07-24-2017, 04:44 PM

Quote:

Originally Posted by bobgaudette

I knew water would come in as when I removed the two plugs I got water so when I took hose off I raised it up. Any thoughts on the broken screw? It's the top right looking from the hose side. I can't get pump off because of it. I might try getting a hack saw blade in there to cut it off so I can at least get the back plate off and see if I can remove the screw end once it's out.

Can you post a picture of this screw, I'm not following when you cannot remove the pump is the head is broken off.