I have a 1977 70 hp evinrude that is not pumping water to the engine correctly. I changed the water pump after I sucked up mud or sand in the motor and it stopped pumping . I also replaced the thermsotat but still no water. My motor has no tell-tail(pee hole) so I watch the exhaust port holes for spray which never happend. I also didnt let the motor run for more then 30 seconds or so and kept my hand on the block to make sure it didnt get too hot-It did get hot. Any suggestions?
You might try the hose on the water tube trick reddog. Drop the lower unit and connect a garden hose directly to the water tube. Remove the t-stat and leace the cover off. Turn the water on and see what comes out. You might have a mud pack in there some where.How hot did the engine get....?
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I had done that when it stopped pumping but I hadnt removed the thermostat - I did remove it today and tried putting water in it and did notice it was slow to drain considering the size of the hole.- I hate to drop the lower unit again but if thats what it takes .
The engine got hot to touch so shut it down . Ive always been told as long as you can keep you fingers on the block your ok but if it starts getting to hot to leave there - shut it down.
As OBJ said pull l/u and flush the motor, also while you've got the l/u off may as well pull the impeller housing and make sure the woodruff key is in the slot and the impeller locked in place on the shaft. Never hurts to double check
Well I did all that (except doublecheck the impellor key) and found the tube had somehow missed the tube completely. After fixing that still nothing.It seems water isnt getting down the front of the motor and out the 6 holes tht are just over the top front of the lower unit.Is it possible a bad seal of the t-stat cover would not let the pump prime????I hope I havent damaged the motor.
Did you replace the pressure relief valve, grommet and spring? Also I know it may sound trivial but it is possible to install the impeller backwards. Its an easy mistake to make if its not something you do often, there's a diagram in the manual that shows the proper rotation.Just a thought
mcm - no I didnt replace the 2 plastic valve or spring .As far as the impellor being installed backwards - I assume the impellor would right itselfbeing it doesnt actually bend in ether direction.What would be the proper direction for the impellor to turn looking down at the lower unit???By the way I have no manual - Im working on getting one.
Well if your looking down the fins should be bent pointing counterclockwise, however when I install mine I install it in the housing first and then slip it over the shaft in which case if you're looking down at the inside of the housing the fins would be pointing clockwise. Like I said its just a thought. Also experience and expensive mistakes has taught me never assume anything
Reddog, since you don't have to pull the head cover to replace the t'stat, try removing the stat and valve and start the motor, let it run for a minute and see how much water (and other things come out). Then shut it down before it gets hot.Maybe the w/pump will flush the motor, you should also be able to tell by the flow if the pump is working properly
Mcm - removed the theromostat cover and tried running it - nothing . The impellor doesnot does not have a bend of its own unless it put in the houseing. Ill check the impellor direction but shouldnt it right itself in the direction it needs to bend??????????????
Once installed in the housing it will have the bend.The manual has a diagram for the proper impeller instalation. The lack of water indicates a problem, either the impeller is not locked on the shaft by the woodruff key, or??, either way you'll have to pull the l/u to find out
I must say ive learn how to pull a lower unit really fast doing this but hey its a learning experiance for me.Im checking it now and will fill you in shortly.
That little key is easy to knock loose, if you install the impeller in the housing first then slip the assembly over the shaft and down over the key you should be able to tell if it locks on the key by trying to rotate the housing
well it appears the impellor faces the correct position and the key was in and locked. I never realized how off center it is to the houseing and how it bends so much. By the way I remeber it pumping alot of water the first time when the tube wasnt conected right because it came out just above the lower unit at shift rod.Once I conected the tube right I got nothing to the motor.Is there a rubber band that goes around the tube to make it fit the houseing tightly? The water pump kit I purchased has a rubber band like thing - of course no directions.
That rubber band is an o ring that fits on the drive shaft, its important not to leave it off but I'm not sure it would affect the amount of water, on the other hand it sound like you may have an obstruction in the water tube in the exhaust housing or in the motor passages
With the l/u still off get a high pressure nozzle on a hose and insert it in the water inlet tube and see if you can dislodge any obstructions, it may help to remove the t'stat when you do this also. Try it both ways
I have tried that and it seemed like everything was flowing ok although I cant recall if it came out the thermostat cover.The rubber band is about a 1/2 inch across . I have a o ring at the top of the drive shaft-is that what you are refering too?
Yes I've heard the o ring called a few things,Her's a diagram and parts list, click here, it may help, not sure what the rubber band is unless its the liner for the housing
The rubber band is a grommet that goes in the water tube guide.Would that cause me not to get enough pressure to have water flow if it wasnt installed?
Now that I think about it the water tube guide slides into water tube in the exhuast housing, the grommet provides a seal between the water inlet tube in the housing and the w/pump housing. Without that grommet there's nothing to stop the water from going up and right back down the water tube, never getting to the motor
Evinrude not pumping water right????
I changed the water pump after I sucked up mud or sand in the motor and it stopped pumping . I also replaced the thermsotat but still no water. 
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