gripit

I have a 420 HP and want to remove the sea water pump impeller. There is a single belt from the center engine pulley to the sea water pump. What is involved in loosening this pulley so I can remove the sea water pump? Is anybody familiar with this engine setup? Thanks

Active Mike

If it is a Merc original sea pump there should be a idler pulley that you need to loosing and then just pop the belt off. The idler pulley should have a nut on the front side of the pulley, you will have to hold the stud with another wrench as you break the nut loose. By turning the stud as you would to try to tighten a bolt will run the idler pulley up or down which will tighten or loosen the belt.
I hope this helps you.

FloridianSon

There should be a C clip on the end of the idler shaft, remove it then a 5/8 wrench just losen the nut enough to relax the belt. I myself take off the hard fuel line and the vent hose and leave the carb line hooked up because it is rubber .If it is hard line remove it to,then take off the water suction line from the pump and if you can reach it and take off the discharge line if it is not a problem.Then remove all the bolts that hold the pump to the frame work just not the one that has a nut on it and your half way there with the pump in your hand.. Remove the last bolt and nut the plastic housing,impeller.wear plate and the quad ring.Replace with a new quad ring,new wear plate and put the new impeller on the shaft and put some soapy water on the impeller and with the pully faceing down spin on the new housing on clockwise till it is just about all the way on 1/8'' then aline the wear plate and the housing up to the right holes and snug up, not tighten the bolt that had the nut on it,then just start all the outher bolts on the frame work rehook up everthing else and your ready to go.

gripit

Can you identify the "C clip on the end of the idler shaft" to loosen the belt in the diagram (link below). I don't know how to loosen the belt in this setup. Thanks

http://media.stemtostern.com/LSDATA/...R\16286\37.GIF

Active Mike

Gripit,
My last instructions was for the combo sea / fuel pump.
What you need to do to be able to adjust your belt tension is loosing the bolts to the mounting bracket and the brace at the engine block. then move pump and re-tighten.
Reverse to remove. You will want the belt to depress about 1/4" between the pulleys when you put it back together.

Griff

There isn't one on that style. It is a different setup than most are used to. Is that the one you have???? If it is it looks like #34 is your adjustment arm. Loosen #38 and #40. You will probably have to also loosen the the other bolt on the bracket that acts as the pivot point also.

Active Mike was refering to this type of idler set up.
http://www.mercruiserparts.com/Show_...2550+AND+UP%29

FloridianSon

My bad to.

Active Mike

Gripit,
How did you make out?