1976 omc not pumping water above 2000 rpm

[norcal racer]

76 omc stringer not pumping water above 2000 rpm at idle is fine and up to 2000 and quits pumping water new impeller and still same problem. pulled both hoses off rear off exhaust manifolds ( the Fills) and they do not pump at idle untill i re connect them from intermidiate back on th rear of manifolds, then i get water through both exhaust manifolds forward uo to thermostat housing but above 2000 rpm zero water any ideas? thanks

 

[norcal racer]

Re: 1976 omc not pumping water above 2000 rpm

help please

 

[TLL]

Re: 1976 omc not pumping water above 2000 rpm

Did you replace both the impeller and the housing, I rarely see a good housing. Also did you apply permatex #2 to the bolts and both sides of the impeller plate during assembly? It is very common on this unit to get exhaust gasses into the cooling water supply. Check the seals where the waterpump housing enters the lower gearcase bushing. Check trunion side covers and stainless plates for proper installation, a plate installed upside down will block of 50% of the water flow to the engine.

 

[norcal racer]

Re: 1976 omc not pumping water above 2000 rpm

ill try that today thanks

 

[Howard Sterndrive]

Re: 1976 omc not pumping water above 2000 rpm

you're sucking exhaust gases.
to remedy this, grease the swivel bearing - grease fitting is through a hole on the front nose of the exhaust housing just below the exhaust hole of the intermediate.

 

[norcal racer]

Re: 1976 omc not pumping water above 2000 rpm

i thought exhaust,so i dissasembled impeller/housing re sealed everthing installed new o-ring re assembled,removed thermostat housing checked and resealed. removed bothe exhasut hoses ( since they keep burning anyway rite now) i have drive in big feed barrel plenty of water, start up pumps great rev to about 1800-2000 no water coming through exhaust at this rpm. again exhast is not hooked up to drive at this point and no water?

 

[norcal racer]

Re: 1976 omc not pumping water above 2000 rpm

oh yea i also removed both side caps and checked o-rings and seals ( ok)

 

[bugzy_1]

Re: 1976 omc not pumping water above 2000 rpm

Is there a key for the impeller? Is in installed? The impeller could be spinning on the shaft at high RPMs instead of pumping. Just a thought!

 

[norcal racer]

Re: 1976 omc not pumping water above 2000 rpm

yea i wish not but the key is in with new impeller checked twicw now!