Mercruiser MCM 120 153 CID ser#5875114

[dkeefe46]

I am rebuilding this engine for my son and this is my first marine engine. I can't get the front hub off of the crankshaft. There is no bolt in the front as in a car engine and I can"t see anything else holding it on. Is it a press fit? I tried a puller and some heat, but not too seriously as I am not sure about this.
Also does anyone know where I can find out the year of this engine? Will a chevy gasket set work?

 

[Alumarine]

Re: Mercruiser MCM 120 153 CID ser#5875114

Can't help you with pulley removal. Mine uses a harmonic balancer which is a press fit - not sure about yours.

I believe it's a 79-82.

Sealed Power might have a marine gasket set for your engine. They do for my 140.

 

[Boomyal]

Re: Mercruiser MCM 120 153 CID ser#5875114

The critical gasket for marine use is the head gasket. It needs to be stainless steel. An automotive gasket will just go away in the absence of coolant.

 

[Buttanic]

Re: Mercruiser MCM 120 153 CID ser#5875114

A puller and more grunt should get it off. They are driven on with a wood block and a big hammer

 

[whywhyzed]

Re: Mercruiser MCM 120 153 CID ser#5875114

153's don't have a harmonic balancer on the front. 4 small bolts and the pulley should fall right off.
181's use a harmonic balancer which requires a puller tool.

 

[Don S]

Re: Mercruiser MCM 120 153 CID ser#5875114

While it doesn't have a harmonic balancer, it does have a hub on the end of the crankshaft that needs to come off so the timing cover can be removed. A puller is used to remove the hub.
When installing it, there is also an installation tool so you don't have to beat on it with a hammer and block of wood. That's real hard on the thrust bearings for the crank.