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Johnson 15hp won't pee, water pump is good... Help a Newbie!!

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Phunkie99

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I'm a total newbie to outboards, but I've immersed myself into it to learn (I tend to do that with new hobbies). I just bought a Jon boat with 1983 Johnson 15hp (J15RCTA) seems to run fine except nothing comes out of the tell tale (pee hole)... Nothing. It ran on muffs when I bought it and figured maybe bad water pump or it just needed to be submerged. Got it home stuck it in a clean garbage can with water well above the intake holes. Still nothing. I took the lower unit off to look at the water pump, and impeller was in good shape no cracks or uneven spaced blades, shaft rotates. I took the hose off from the pee hole to the block it was clogged, cleared it and the hole itself... Still nothing. I just tried spraying water up the copper tube and blowing air in it water came out the exhaust and air could pass. Stuck a tube against the pee hole and tried to blow air in, and no air would pass so I think my blockage is in the block somewhere. What should I do next? Any help would be greatly appreciated for this lost rookie.
 
I a relative newbie... I put my '87 Merc 8 hp in garage six week ago after a successful day. No fish, but motor ran well and peed fine. All told motor ran start stop 30 minutes while I kept checking tell tale. Tis was a test running.
After six weeks, I started in a full tub of water and it did not pee after several attempts. Never let it run over 10 seconds from a cold start.
Tube from thermostat outlet is clear. I pulled the cover, discovered there is no thermostat in the engine. I started to see if water was circulating up - 10 seconds, no water flow. I've checked the lower screen intake and do not see any clog. I bought it as a fully rebuilt in March. Only had it in the lake the once described above.
Thanks

Is my next step to drop the lower unit to check the impeller?
 
Phunkie99 said:
I'm a total newbie to outboards, but I've immersed myself into it to learn (I tend to do that with new hobbies). I just bought a Jon boat with 1983 Johnson 15hp (J15RCTA) seems to run fine except nothing comes out of the tell tale (pee hole)... Nothing. It ran on muffs when I bought it and figured maybe bad water pump or it just needed to be submerged. Got it home stuck it in a clean garbage can with water well above the intake holes. Still nothing. I took the lower unit off to look at the water pump, and impeller was in good shape no cracks or uneven spaced blades, shaft rotates. I took the hose off from the pee hole to the block it was clogged, cleared it and the hole itself... Still nothing. I just tried spraying water up the copper tube and blowing air in it water came out the exhaust and air could pass. Stuck a tube against the pee hole and tried to blow air in, and no air would pass so I think my blockage is in the block somewhere. What should I do next? Any help would be greatly appreciated for this lost rookie.
Click to expand...
Sounds like you may to take the head off possibly/ and or the thermostat cover.?Check condition of thermostat.Rubber grommet On bottom of block for copper tube does not sound like it’s collapse if you blew water and air through it.
 
don1972 said:
I a relative newbie... I put my '87 Merc 8 hp in garage six week ago after a successful day. No fish, but motor ran well and peed fine. All told motor ran start stop 30 minutes while I kept checking tell tale. Tis was a test running.
After six weeks, I started in a full tub of water and it did not pee after several attempts. Never let it run over 10 seconds from a cold start.
Tube from thermostat outlet is clear. I pulled the cover, discovered there is no thermostat in the engine. I started to see if water was circulating up - 10 seconds, no water flow. I've checked the lower screen intake and do not see any clog. I bought it as a fully rebuilt in March. Only had it in the lake the once described above.
Thanks

Is my next step to drop the lower unit to check the impeller?
Click to expand...
Shouldn’t you start your own thread in the MERCURY THREADS for the proper help?
 
I was afraid of that. Any pieces of advice. I think I need a Torque wrench and find out the proper weight for the center bolt??? YouTube here I come...
 
Is it a salt water motor? Just rebuilt this vintage Yamaha. Ran great....kept plugging P hole. Miami motor....guy flushed it religiously....sure he did. Used a block off an old Mariner. No way could have removed that much oxidation and seawater deposits.....sand too. Think it had half of Florida Bay in it. 13425_compress73.jpg
 
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Phunkie99 said:
1983 Johnson 15hp (J15RCTA) seems to run fine except nothing comes out of the tell tale (pee hole)... Nothing.
Click to expand...
Is it overheating at all? For example, when you run it, does water or steam come out the exhaust bypass holes?

I have a 1979 Evinrude 9.9 and I fought a similar problem. The first easy step is to remove the exhaust covers on the starboard side of the engine. The outer plate (#23) has channels where the water runs and you can get crud built up there. Under the inner plate (#24) you can see the water passages in the block.
Block.png

It's also possible you have crud in the thermostat housing (#6)
Tstat housing.png

I did all of that on mine and still had low water flow problems. Finally, a great guy that used to be on this forum for a long time, Joe Reeves, pointed me in the right direction. These small motors had a grommet on the top of the the water tube where it meets the block (Part# 0324045) that would deform and restrict water flow. You have to pull the powerhead to get to it and sure enough, mine was turned over on itself and barely had an opening the size of a pencil lead. After replacing the grommet it's ran great ever since. Hopefully you don't have to go that far, but it's a possibility.

The grommet is part #39 in this diagram:
Grommet.png
 
It doesn't seem to be over heating. I have a feeling that the 90 degree elbow that is attached to the block and then leads to the hose to the pee hole is totally blocked. I cleaned out the nozzle, with a metal tooth pickin tool, but I can't get around the corner. I'm pretty sure I'm gonna break it if I try and remove it.
 
Excellent advice Kevin. Sure miss Joe, he has been the backbone of this forum, he still chimes in from time to time. The OP mentioned good water flow when water was directed up the copper inlet tube so I kinda ruled that out. What tends to deteriorate that o ring/seal is often excessive fuel/oil accumulation in chamber area there. It will eventually lead to the destruction of the motor mounts causing great concern and problems with operation. These motors were engineered to run at 100:1, but on specific oils. I have extensive experience with this generation of motors and operating them at 100:1, often freighting in remote locations in NW Ontario. Amsoil 100:1 pre mix or Amsoil Saber, far exceeds OMC's specifications on 2 stroke oil. These synthetics ensure phenomenal lubrication at 100:1. This is what I use, my customers use, and I strongly recommend to prolong motor life. One key factor is NEVER use any ethanol fuel. Ethanol will damage crank seals, motor mounts, cowling insulating foam, and anything made of rubber/latex composition. This includes a host of synthetic materials commonly used in fuel systems. If the gas station doesn't have a dedicated non oxy hose on the pump, make sure either non oxy was the last sale......or pump a gallon first into your car / truck / or another can. Just had a little Merc repair this month, where the owner....."I never thought of that"....... Cost him $140 bucks to learn.
 
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They were not " engineered " to run at 100:1.-----Parts of the 50:1 models and 100:1 models are exactly the same.-----The board room decided to label motors at 100:1 because the general public believes that a 100:1 motor must be a better motor than a 50:1 motor.----The general public is not well versed in 2 stroke operation and lubrication !!!
 
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