hot mercury

[zanx]

i am seeking imfo. on a overheating merc.150its about a 90 to 93 motor,i have been through everything new thermostats,good pump,temp. sending unit etc. i was wondering if merc.s had a rubber grommet on the water pick up tube under the power head? i got the motor recently so i dont know weather its ever been run hot before,being familiar with outboards i have run into this prob. before with other brands,just not familiar with merc.s HELP! p.s. its got good compression and a nice even burn on the plugs,the motor will runup to 3400rpms without sounding an alarm anything beyond that hot!!

 

[jegervais]

Re: hot mercury

Did you check the poppet valve and springs?? Double-circular cover on the lower starboard side of the block, held on by 4 (maybe 5) bolts. I believe you will find it helpful to remove the lower motor cover on that side in order to gain access. The poppet controls cooling water flow for hi-speed operation, is supposed to unseat and flow max water around 2500 rpm's (?? I think).<br /><br />-John

 

[zanx]

Re: hot mercury

thanks john,thats why its nice to be able to talk to someonelse,two heads are better than one,will check and reply.

 

[zanx]

Re: hot mercury

hey john,checked poppet,all looked well while i was in there i replaced the diaphram seat and gaskets,still the same problem.i know the motor was overheated at some point,but there is a fresh power head on it.i saw that there was a rubber grommet under the power head b/t the center section and the water pickup tube,i am wondering if it got swolen up and is restricting flow?

 

[rod102]

Re: hot mercury

Did you ever figure out what was wrong with your motor? I have a 200 h.p. that is doing the same thing. It is a 1991 model 2.4 litre.<br />thanks<br />Rodney