I have a 2002 40HP 2-stroke Mercury that is not spitting out water consistently. I thought it was the impeller, so I put in a new one, and it’s still not spitting out water very well. Even at WOT it kind of just sprays water out doesn’t really make a nice stream like you’d expect.
I’ve tried to see if the ejection port was obstructed by shoving the end of a bottom bouncer in there but it seemed fine, what other things can I do to troubleshoot or fix this?
thanks in advance!
A “slight” blast of air up the water hole should push out any obstruction.
It’s best to test at home with a hose prior to hitting the water.
from the outside or do I unhook a hose or something? if I do it from the outside, where am I blasting this “obstruction”?
push air up the pee hole on the outside of your motor, becareful NOT use alot of pressure,not sure what would happen if you do tho ,but I was always told a slight pressure will work just fine.
Not sure where obstruction goes ,but it has ALWAYS work great afterwards for me 
If slight air pressure does not work, follow hose up to thermostat housing to make sure there is not a kink. Remove at thermostat housing and blow outward. Obstruction will go into thermostat housing otherwise, but is not big enough to cause any problem. Will pass through and out the bottom through the main water channel. Most likely a piece of plant or wood. If that does not work, you need to check water pressure with a gauge.
thanks tsamp, I’ll try that..
anyone know if the “ear muffs” from gander will work on this lower unit?
Or a chunk of your old impeller? Maybe that is why it is spraying and not a line of water.
I’m not sure that I agree with pushing air up the pee hole. That way you are pushing the obstruction further into where you already DON’T want it to be.
What I’ve seen happen is that the impeller sucks up mud, sediment, sand, etc and the indicator outlet (“pee hole”) is the most constricted point of the system. It’s essentially like the spray nozzle on your garden hose, it confines the stream.
Since this is the narrowest point in the system, the debris starts to back up from the indicator outlet, back into the hose. It might start with just a few grains of sand, but slowly more and more debris builds up in the hose until it can become completely blocked.
Here’s what I’d do:
– Take the cowling off.
– Find the point where the indicator stream hose connects to the fitting that goes through the cowling and out side. Disconnect the hose at this fitting. How you do this depends on the outboard, some have camps, some are just a pressure fit barbed fitting, etc.
– With the hose disconnected, use a small pick or other object to gently clean the indicator stream fitting.
– Now put the water muffs over the intakes and turn on the garden hose to supply cooling water.
– Start the engine and run it with the indicator stream hose still disconnected from the fitting and pointed over the side of the engine.
– Gently squeeze the hose in your fingers, working from where it connected to the fitting backward. If there is debris backed up in the hose, it should come spurting out. Let it run for a while even after debris comes out. You want to make sure you flush everything and sometimes if it’s mud it will be dried in the hose and take a while to loosen up.
– Reassemble and use new hose clamp (always stainless) if necessary. Do not overtighten.
– Test again to make sure when hose is reconnected to indicator stream fitting the problem is solved and the proper indicator stream pattern forms.
Grouse
Quote:
I’m not sure that I agree with pushing air up the pee hole. That way you are pushing the obstruction further into where you already DON’T want it to be.
What I’ve seen happen is that the impeller sucks up mud, sediment, sand, etc and the indicator outlet (“pee hole”) is the most constricted point of the system. It’s essentially like the spray nozzle on your garden hose, it confines the stream.
Since this is the narrowest point in the system, the debris starts to back up from the indicator outlet, back into the hose. It might start with just a few grains of sand, but slowly more and more debris builds up in the hose until it can become completely blocked.
Here’s what I’d do:
– Take the cowling off.
– Find the point where the indicator stream hose connects to the fitting that goes through the cowling and out side. Disconnect the hose at this fitting. How you do this depends on the outboard, some have camps, some are just a pressure fit barbed fitting, etc.
– With the hose disconnected, use a small pick or other object to gently clean the indicator stream fitting.
– Now put the water muffs over the intakes and turn on the garden hose to supply cooling water.
– Start the engine and run it with the indicator stream hose still disconnected from the fitting and pointed over the side of the engine.
– Gently squeeze the hose in your fingers, working from where it connected to the fitting backward. If there is debris backed up in the hose, it should come spurting out. Let it run for a while even after debris comes out. You want to make sure you flush everything and sometimes if it’s mud it will be dried in the hose and take a while to loosen up.
– Reassemble and use new hose clamp (always stainless) if necessary. Do not overtighten.
– Test again to make sure when hose is reconnected to indicator stream fitting the problem is solved and the proper indicator stream pattern forms.
Grouse
I agree with this – I have the same motor and had the same problem. Re-did the impeller and still had the problem. I did what Grouse says and it worked. Yes, I use ear muffs to check it. Mine were from Fleet/Farm, but I am guessing about the same. Good luck
I also had the same problem with my 40HP Merc last year. I did the same sort of thing grouse suggested. It would work…and then not. What I eventually had to do was take it in and the mechanic said he was somehow able to flush out the system. Had sand/mud circulating within the block somewhere. It’s worked fine ever since. Cost me about $80 as I recall. Good luck.
Quote:
I also had the same problem with my 40HP Merc last year. I did the same sort of thing grouse suggested. It would work…and then not. What I eventually had to do was take it in and the mechanic said he was somehow able to flush out the system. Had sand/mud circulating within the block somewhere. It’s worked fine ever since. Cost me about $80 as I recall. Good luck.
If you’ve sucked up any quantity of mud into the system, it can take a lot of flushing to clear it all out.
I think what happens is that the mud dries in the water passages or inside the hose and then you have to run enough water through the system to rehydrate all the mud so that it will flush out. If you don’t flush it long enough to get the mud rehydrated, the indicator outlet just clogs again.
Grouse
Maybe it’s operator error?…. 
will somebody please BAN this troll!
Out of these water flushers, which one would be the most appropriate?
Universal, Rectangle, Pro?
I have also seen impellor blades that have come apart and sucked up into the water tube and wedged in at the bottom of the water jacket, nearest the water tube. Make sure to shine a light up inside and take a peek, plus blow out the tube and make sure the tube is free of obstruction. 
I bought the rectangular ones (looks like the first one pictured) at FFarm and they seem to work fine.
Also for the people that commented about similar experiences with the same motor, after cleaning the lines out and what not, how fast did it take to clog back up?
In my case, after I cleared the line (the one leading from the block to the pee hole), it would sometimes take an hour or so of use before it replugged. I bet I did this (clear the line) a dozen times. That’s why I got sick of dealing with it and eventually took it to a mechanic who had to blow out/clean the sand/mud from inside the block. Or so he said. Must have worked, cuz since then it’s been trouble free.
Quote:
will somebody please BAN this troll!
I had a 7.5 HP Johnson that I bought last summer that was blocked up solid with mud.
I used the process I described above. The hose was full of mud, when it came loose there was probably have a cup of gunk that came out.
Then I let the motor run in a test tank for about 20 minutes with the line still disconnected from the indicator fitting. I’m sure more dirt came out, but after that I never had to re-do it.
I think it all depends on how much crap got sucked into the system and where it’s stuck. It could be a couple of grains of sand lodged right in the indicator stream fitting, or it could be a cup of muddy gunk spread out through the system.
Grouse
Well I unhooked the hose from the fitting off the motor and there is no water running out of there at all..
Couldn’t find any obstructions but I think the thermostat is the culprit. Going to try replacing it tomorrow and see what happens.
Working perfectly with the new thermostat..
Schwing!!!!!!! Way to stick with it!
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