1973 80hp merc water presure

[wishinIwasFishin]

g'day mate's<br /><br />just a quicky<br /> what water presure should I expect out of this old darling and do these old girl have a higher compession than other makes and models (i've just bought her )<br />shes runing 152psi in no.1 <br />150psi in no.2<br />153 psi in no. 3<br />155 psi in no. 4<br />how does this sound to you blokes and shielers<br /><br />cheers Daryl<br /><br />ps looks to be well looked after.

 

[RICKRICK1]

Re: 1973 80hp merc water presure

Compression is great, water pressure at idle should be about 3psi at wot 6 to 8 psi.<br /><br />If you just got this motor I recommend changing the water pump impellar as you do not know how long its been in use, also service the lower unit.<br /> Hope this helps.

 

[wishinIwasFishin]

Re: 1973 80hp merc water presure

thanks rick<br /><br /> do these motors have heads as such and do they normaly run higher compession then others.<br /><br />cheers Daryl<br /> _____________________________________________<br /> A bad day fishin is still better than a good day workin

 

[ledgefinder]

Re: 1973 80hp merc water presure

The head and cylinders are all one casting, as they are on most Mercs from that era. For what it's worth, my 1971 Merc 80hp also measures right around 150psi. If you're nervous about running that compression with today's gas, how about knocking back the max timing a couple degrees from stock?