No water circulation? Please help

[Kimberly80]

My ex left a johnson 1974 40hp model number 40rl74s in my building. after i went thru the motor and got it run, I noticed the head was getting too hot.
Its not circulating water . I put a new impeller in the l.u and drill tested it while in a bucket before reintsall
I made sure to install a new o-ring in the intake tube also. Reinstalled the l.u and still no water comming out of the exhaust relief port, my motor doesnt t-stat... here are the things I've done...to keep it short.

1)put a water hose on the intake tube that's connected to the powerhaed and get good flow outta the head.
2) removed the water cover from the cylinder head. Started motor only drops of water and exhaust comming out of the water passageways .

3) I replaced the head, headgasket, water cover gasket, my compression is 110 on both cylinders.

I then start the motor "in a barrel" still no water is comming out. Btw..the water level in the barrel is 2" below the exhust relief port.
If I remove the little cover on the were you unscrew the shift linkage water starts to spray out the exhaust relief port and the head immediately cools ....

Only other cause would be the mounting gaskets or a cracked intake tube? Anyone have thoughts?

 

[Scott Danforth]

sounds like you have a blockage preventing water from hitting the impeller as indicated when you remove the access cover allowing water to run in.

 

[Kimberly80]

Hey scott
Water is already present beacuse i only run it in a barrel, Foot was cleaned and all passages were inspected. And spun gear shaft clockwise with a drill, before I installed the foot, Water shot out

The water starts to flow if I remove the linkage access plate cover located in the leg it allows exhust pressure to exit then I get circulation.

 

[Kimberly80]

My parts diagram doesn't show a inlet tube grommet, just wanna know what to look for if the head needs to come off,

 

[muskyfins]

We have a late 70's 35 Johnson on our hunting rig. Probably once per year, we found blockages in the tube where the water should exit. It's surprising how small of a blockage it takes and won't push through. Look where the fitting is screwed into the head and remove that fitting. Eventually, we went with new fiittings and bigger hose.

 

[Kimberly80]

Hey musky,
What fitting?
Are you talking about the "tell tale" hole?

 

[oldboat1]

Think I would try to back flush through the exhaust relief and the port on the leg. If that doesn't get exhaust and water flow moving, pull the l.u. and look up in the upper leg under the powerhead -- mud dauber or mouse nests.

 

[Kimberly80]

I checked for blockages. Whould that cause exhust to enter in the cooling system? I know these are simple cooling systems, but this has me stumped.
If I remove the cover on the leg were the shift linkage is, water starts a heavy spray out the exhaust relief port as it should, the head immediately cools .

 

[oldboat1]

don't think I've quite heard of that one. But many motors have vent holes on the side of the leg, maybe a few inches below the powerhead. Vent holes are filled in, maybe an airlock is created. The holes would be about 1/8 inch, and found in various locations.

 

[flyingscott]

Is the tube lined up correctly into the water pump housing?

 

[Kimberly80]

You could be on to something about the vent holes..
Ill have to check and see. Ty

 

[racerone]

When you put the lower unit on is the copper tube installed in the grommet in the exhaust housing ?----Or is the tube stuck in the waterpump housing.---The tube must be installed into the exhaust housing FIRST !

 

[muskyfins]

Hey musky,
What fitting?
Are you talking about the "tell tale" hole?

Sorry, I miised getting back to you sooner.

Yes. The tell tale. If you look inside the motor housing where water should exit through the "pee" hole is a rubber grommet outside and a hose on the inside. Follow the hose. The other end is connected to a fitting on the block.

 

[racerone]

The 74 model 40 hp did not leave the factory with a tell tale fitting !

 

[muskyfins]

The 74 model 40 hp did not leave the factory with a tell tale fitting !

So the hose runs through a hole in the lower cowl area. Right?

Same hose. Follow to other end.

 

[oldboat1]

Might be thinking of the inner and out exhaust housings on early 40s (earlier than '74, I think) -- water and exhaust routed out through a boot. Not a tell tale as in modern motors, but can serve like one. If water isn't exiting through that bypass, safe to assume the water pump isn't doing its job. Personally, it's enough of a tell tale for me, but a lot of folks prefer the little pisser.

 

[racerone]

No the 74 models did not have that rubber boot !!

 

[Kimberly80]

The problem wasn't in the impeller assembly the drill test proves that.

 

[racerone]

So, was the water tube installed in the exhaust housing grommet first, yes or no.--------------You can not install the lower unit with the tube stuck in the pump first !!

 

[clemsonfor]

There is something blocking flow to the motor, you unfortunately will have to pull the LU and check that tube out and all, if the pump works as you say it does it should be putting water up to the block. Pull thermostat housings and pull the tube in the lower unit out, it may have crap lodged in it, piece of grass, old hunk or impellor, something is stopping the flow, which you clearly realize, but the only way to find out is to double check your work and start pulling stuff apart.