water pump problem?

[jrocksho]

1990 mercury 150xr4. i've already posted my problem with not much help, but still much appreciated. i have some more info that might help. i ran on muffs and i could feel air coming from tell tale. water pressure is higher than normal at idle and while running. sometimes, maybe after it warms up, i do get water from tell tale, but no steady stream, it spits out as if air is present. 2 questions: can air move needle on gauge? could this be a problem with lower pump housing? i've never changed it yet, always just the top half. oh and the screw near the water tube outlet on upper housing is stripped and doesn't tighten down, could i be getting air from there? it still seems very tight with the main 3 nuts so im not sure if that would be a problem really. like i said before, this is my third time replacing this pump assy, every time was the same until this time. now im having problems i think. it doesn't overheat but it does seem to get warm quicker than i remember, but it stays steady temp at idle and very cold while running with higher than nomal pressure.

 

[hotrod53]

Re: water pump problem?

After 12 years, you need an impeller anyway. The impeller is nothing more than a rubber water slinger, if it is not pumping, it's more like a restriction not allowing water to pass or pressurize. Without a doubt I would start there.

 

[carholme]

Re: water pump problem?

The fact that you are noticing higher than normal water pressure is indicative of a partial blockage in the system. Have you pulled the thermostat and poppet valve to see if they are hanging up/corroded at all. You can do a simple test of the thermostat in boiling water.

The fact that it is not going hot and is indicating water pressure would suggest that the impeller is functioning.

Parts listing:

http://www.crowleymarine.com/mercury-outboard/555.cfm


Gerry

 

[jrocksho]

Re: water pump problem?

hotrod, i dont know where you got 12 years from. i just replaced upper pump assy 3months ago and this all started. this is my 2nd time replacing in the 21/2 years i owned the boat, not 12.

 

[coastalrichard]

Re: water pump problem?

hotrod, i dont know where you got 12 years from. i just replaced upper pump assy 3months ago and this all started. this is my 2nd time replacing in the 21/2 years i owned the boat, not 12.

Was the previous impeller intact when you replaced it or was it damaged (fins torn, missing)? If the latter, perhaps pieces got pumped into the cooling system and clogging it. It doesn't take much to impede water flow. Just a thought...good luck!

 

[jrocksho]

Re: water pump problem?

well after i changed pump assy, it still overheated while idling. so i changed both tstats and poppet assy about 2 months ago. temp is fine now, can idle forever. i also ran with stats completely out and still same problem. so im thinking the lower pump housing or head gaskets may be sucking air into cooling system. im hoping someone here thinks the same? lol. or at least tell me thats possible cause or am i wasting my time looking at these parts.

 

[jrocksho]

Re: water pump problem?

no impeller was in good shape. thanks. only a year old. i was getting 23-25psi wot with last pump, after i changed it this time, im getting 28-30psi and not steady, it surges as if maybe air is in system and only spits out of tell tale, not a steady stream of water

 

[jrocksho]

Re: water pump problem?

restriction is possible, i checked all hoses and they were clear. it would be internal if it is partial blocked. the only reason i dont hink its blockage, i can feel a steady stream of air from tell tale and the higher readings on gauge could be air moving the gauge and not just water, which is thinner and i think air would have higher pressure than water. also cus it surges and not steady. at idle it goes from 7psi-12psi and keeps bouncing, while running, same thing, itll go from 24-30psi bouncing. i hope its air, easy fix head gasket or lower housing seals. i dont know. thanks

 

[Treker57]

Re: water pump problem?

Have you tried running the motor with the lower unit submerged in a large trash can

 

[coastalrichard]

Re: water pump problem?

restriction is possible, i checked all hoses and they were clear. it would be internal if it is partial blocked. the only reason i dont hink its blockage, i can feel a steady stream of air from tell tale and the higher readings on gauge could be air moving the gauge and not just water, which is thinner and i think air would have higher pressure than water. also cus it surges and not steady. at idle it goes from 7psi-12psi and keeps bouncing, while running, same thing, itll go from 24-30psi bouncing. i hope its air, easy fix head gasket or lower housing seals. i dont know. thanks

Well git with it bud, the Redfish are biting

 

[jrocksho]

Re: water pump problem?

no, only in bayou or on muffs. no difference either way.

 

[jrocksho]

Re: water pump problem?

yea i know you right. they been biting good here for weeks. i have time though, they always biting down here

 

[jrocksho]

Re: water pump problem?

i finally found and fixed my problem. i had a blown cylinder cover gasket. now everything checks out good. the high water pressure was from that cylinder pushing air into my water system and also water was getting into cylinder but no damage, just a very clean piston. thanks again i hope this helps someone prevent the headache i had from it. im going fishin now!!

 

[aussieflash]

Re: water pump problem?

So im confused,you said earlier that changing impeller and tstats and poppet solved your overheat problem.Is it still running cold when up on plane...cause thats a problem.If its good and now runs warm as it should let me know as my engine always runs cold.

 

[jrocksho]

Re: water pump problem?

my problem wasn't overheating, i fixed that. engine was running cold, only waming up at idle. also was spitting out of tell tale, had air mixed with water. i had a blown head gasket, changed it and now engine runs warm all the time and stready stream out of tell tale.