Intermittent tell-tail Merc 150 XR2 Black Max

Jerry Reed

Cadet
Joined
Mar 10, 2004
Messages
6
My mercury 150 XR2 Black Max had sit for about 6 months, when I cranked it I had no stream coming from the little tell-tail port. I replaced the impeller and it seemed ok. Well it sat for about another 6 months, so really maybe an hour of running during that time, and now I started it a couple of days ago, it was running very rough and would not run at idle for any period of time. I put sea-foam additive in the tank, started it. I had to choke it to keep it running for several minutes and I let it set overnight. The next day it started right up, it would idle but a little rough. I cleaned the plugs and it is running much better now but the tell-tail stream quit spraying. I removed one of the thermostats and there was no debris. I pour some water into the tstat hole, put the tstat back in, had a good stream for a few minutes then it stopped spraying again. Do I need to replace the impeller again or what?<br />Thanks
 

Clams Canino

Commander
Joined
Jan 10, 2004
Messages
2,179
Re: Intermittent tell-tail Merc 150 XR2 Black Max

Are you sure it warmed up enough to open the thermostats? also check the pee-tube for debris and mud-wasp mud.<br /><br />-W
 

Dead Eye

Petty Officer 1st Class
Joined
Jan 21, 2004
Messages
259
Re: Intermittent tell-tail Merc 150 XR2 Black Max

Another post suggests a poppet valve. What year is your motor
 

Jerry Reed

Cadet
Joined
Mar 10, 2004
Messages
6
Re: Intermittent tell-tail Merc 150 XR2 Black Max

1984. I'm a newby, where's the poppet valve?
 

Jerry Reed

Cadet
Joined
Mar 10, 2004
Messages
6
Re: Intermittent tell-tail Merc 150 XR2 Black Max

In repsonse to Clams, Yes it is warmed up , enough for my Overtemp alarm to go off. When it is peeing it is very clean. From the few points that I have opened it is all very clean.<br /><br />Jerry
 

KCLOST

Commander
Joined
Jun 22, 2002
Messages
2,095
Re: Intermittent tell-tail Merc 150 XR2 Black Max

Assuming that the stats are working, and the impeller/water pump is in good shape, let's go to the next possible cause.<br /><br />A faulty poppet valve could cause your symptoms. It should be closed at lower rpms. If it is stuck open the water will exit the block before beign fully circulated around the upper part of the engine. The poppet is underneath the switch boxes on the starboard side (right side when looking at it from the rear) of the block.<br />Copy and paste this entire link if it doesn't work for you (it is aweful long).<br /><br /> http://www.dougrussell.com/partscat...berList=120,70,80,20,30,10,180,130,170,140,19 0,40,100,110,90,290,270,250,300,280,260,320,330,350,340,360,0,370,380,400,390,160,150,420,430,410,440,210,200,60,230,240,220,310,50
 

Jerry Reed

Cadet
Joined
Mar 10, 2004
Messages
6
Re: Intermittent tell-tail Merc 150 XR2 Black Max

I have removed the cover from the poppet valve, I didn't have a lot of time once I pulled the cover off, but I did attempt to gently pull on the poppet and it didn't come right out. I don't know if I need to remove the little phillips head screw in the center of the valve or what.<br />Can anyone tell me if I need to gently pry it out or excactly how the poppet is to be removed?<br /><br />Thank You<br /><br />Jerry
 

KCLOST

Commander
Joined
Jun 22, 2002
Messages
2,095
Re: Intermittent tell-tail Merc 150 XR2 Black Max

No, don't remove the screw. You have gotten the relief valve cover off, but there is another metal piece between the plastic washer & diaphram (where the screw is) and the block. Pry on the metal piece gently, its called the relief valve plate and everything should come out except for a grommet or two.<br /><br />There is probably some corrosion under the plate that has it seized on a bit....
 

Jerry Reed

Cadet
Joined
Mar 10, 2004
Messages
6
Re: Intermittent tell-tail Merc 150 XR2 Black Max

I will try that this weekend. Thank you for your input.
 
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