454 mercuiser MPI thermostat
 

Does anyone know if on a fuel injected 454 if you need to remove the intake manifold to get to the thermostat?

If not does anyone have the procedures to remove and replace.

Thanks

No you don't have to remove the intake. Remove two bolts, remove hoses, turn upside down and remove sleeve and thermostat.

Make sure get a factory (#5) 160 t-stat, the gaskets (#4,this you really have to make sure it's Merc as it has rivets to gound the t-stat housing) and 100% make sure you install the t-stat and (#6)plastic t-stat spacer/water flow guide the way it shows in this factory diagram or you'll f*k yourself. To put it blunt. Note how it is orientated.

http://www.mercruiserparts.com/images/COMMON/36327.png

Concur.

and just to add make sure you install the plastic #6 water diverter in the exact spot it was in..you can turn it to put more water to one side to eliminate steam....you mmight crack it taking it out so you may as well ket the t-stat kit woth the diverter..

The plastic diverter has a small nub on it that lines up with an indent in the thermostat housing. Engage the two and you can't mess it up. It's small and on the edge.