Replacing thermostat on Mercruiser 470

[mk160]

I need to replace the thermostat on my Mercruiser 470 (4 cyl, 224 cid, 165 HP). The engine SN is OB749835. I have the thermostat replacement kit, exhaust manifold (sierra 18-0956-1) and elbow gasket (sierra 18-0113-1) on order. Any lessons learned or advice out there? Thanks!

 

[jhamblett]

I need to replace the thermostat on my Mercruiser 470 (4 cyl, 224 cid, 165 HP). The engine SN is OB749835. I have the thermostat replacement kit, exhaust manifold (sierra 18-0956-1) and elbow gasket (sierra 18-0113-1) on order. Any lessons learned or advice out there? Thanks!

Pretty straight forward , I just did mine although the engine was out of the boat. I am in the middle of a alternator conversion so I had the tube off the thermostat to access the voltage regulator easier and to flush the coolant

 

[mk160]

Pretty straight forward , I just did mine although the engine was out of the boat. I am in the middle of a alternator conversion so I had the tube off the thermostat to access the voltage regulator easier and to flush the coolant

Thanks! Looks like four bolts to get the reservoir off and then the manifold. I did my alternator conversion about four years ago, still have my stator!

 

[jhamblett]

Thanks! Looks like four bolts to get the reservoir off and then the manifold. I did my alternator conversion about four years ago, still have my stator!

Wish I had the room to mount my alternator to the side. Mine will have to be up higher.

 

[mk160]

Jhamblett I just looked a little more closely at your second picture. It appears that the thermostat is at the front end of the exhaust manifold and that I should be able to replace the thermostat from below without removing anything?

 

[jhamblett]

Jhamblett I just looked a little more closely at your second picture. It appears that the thermostat is at the front end of the exhaust manifold and that I should be able to replace the thermostat from below without removing anything?

Yes you should be able to. Socket with a flex joint

 

[Eric 3.7LX Alpha 1]

Thanks! Looks like four bolts to get the reservoir off and then the manifold. I did my alternator conversion about four years ago, still have my stator!

Just to let you know, that inline plastic fuel filter isn't coast guard approved for an enclosed engine compartment.

 

[mk160]

Thanks, did not know that. I'm assuming the previous owners had an issue with the stock filter. I'll see what I need to do to replace it.