1984 140Hp Johnson Cooling

Aussie Rob

Cadet
Joined
Jun 20, 2011
Messages
22
Hi all.

Im not sure the problem - just bought the boat.. upgraded ;)

this new one has a 140hp 1984 Johnson - Ive just changed the water pump kit, top and lower seals on the leg.

but noticed that im not getting water from the exhaust ports or from the usual spot on the lower leg when the thermostats open. if anything exhaust.

I can confirm that I am getting water from the telltale, and the heads are flowing water. (I pulled the pipes between heads and thermostat housing)

When I put water into the thermostat housing the water comes out the areas that Ive normaly seen from the incoming water. and still nothing from the lower leg holes at the rear.

I also have a lot of water coming out near the exhaust seal at the join from the mid to the lower leg - both sides.

I also get a lot of black ooze after I have run the motor for a while dribble out of the sides of the leg join and from the front of the prop. assuming more wet exhaust.

No water in lower leg oil.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: 1984 140Hp Johnson Cooling

Do the heads get hot to touch? You should be able to keep your hands on them.

I dont get what you mean here
"When I put water into the thermostat housing the water comes out the areas that Ive normally seen from the incoming water. and still nothing from the lower leg holes at the rear. "

A lot of water coming out near exhaust seal can mean that its being pinched on reinstall
 

Aussie Rob

Cadet
Joined
Jun 20, 2011
Messages
22
Re: 1984 140Hp Johnson Cooling

Do the heads get hot to touch? You should be able to keep your hands on them.

I dont get what you mean here
"When I put water into the thermostat housing the water comes out the areas that Ive normally seen from the incoming water. and still nothing from the lower leg holes at the rear. "

Heads are still touchable since Ive taken the thermostats out. There is evidence that a fire has occurred under the cowling too.

When I put the water in the tube that would normally feed the thermostat housing from the heads - that is when I get it around the water pump/impellor section and not the exhaust relief/etc. mind you I do seem to get a a lot of spray from/with the exhaust.
 

Bosunsmate

Admiral
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Apr 7, 2012
Messages
6,129
Re: 1984 140Hp Johnson Cooling

Id be careful running it without thermostats as you will get a lot of carbon deposits in the rings and risk cold seizing and your pistons will wear prematurely too.

Fire, struth i am guessing the past owner didnt bring that up.
Your exhaust housing could be corroded and thus spray exhaust is going any each way. Id assume its a good old salty motor being where you are, if they arent flushed well the housing can spring holes where they werent meant to. Not really a problem so long as water doesnt start backing up the leg or spray is getting into the exhaust chamber near the cylinder exhaust ports
 

Aussie Rob

Cadet
Joined
Jun 20, 2011
Messages
22
Re: 1984 140Hp Johnson Cooling

I've got new thermostat kit coming - I'm only running on flushing ears at present. I can see my winter will probably be a take off the heads and clean the water gunnels.

I just don't like the idea of putting the old girl on the water without knowing things are going where they are meant to be..
 
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Bosunsmate

Admiral
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Apr 7, 2012
Messages
6,129
Re: 1984 140Hp Johnson Cooling

Yep and replace the water deflectors and take the outer water cover off too as thats where a lot of salt build up happens too
 

Aussie Rob

Cadet
Joined
Jun 20, 2011
Messages
22
Re: 1984 140Hp Johnson Cooling

Yep and replace the water deflectors and take the outer water cover off too as thats where a lot of salt build up happens too


Water Deflectors? where are they? J140TLCRD model if you need it. Found it.


I've also read a bit about people moving the telltale from the low spot of the outer water cover to a higher spot to eliminate air blockages.. = thoughts???
 
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Aussie Rob

Cadet
Joined
Jun 20, 2011
Messages
22
Re: 1984 140Hp Johnson Cooling

I guess I am trying to not have to take the motor off the midsection.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1984 140Hp Johnson Cooling

The engine needs to run with thermostats to keep the block properly filled with cooling water and to regulate the powerhead temps. The telltale nozzle is actually a restrictor, which should cause the block to fill completely, but you can loop the telltale hose up and over the top of the powerhead, then back to the telltale nozzle. The telltale indicates the water pump is working, but does not indicated that cooling water is circulating thru the block and out to the exhaust adapter,then down the midsection. Lack of cooling water out the block is usually attributed to the two stats being stuck shut, or the two small holes in the valve body being plugged. If the stats are out, then I'd be pulling the head covers off to inspect the head cooling passages, even pull the heads themselves and verify the positioning of the water deflectors in the block. Best to use a laser temp gun to check the block temps. Rent at an auto store. Stats will open at 143 degrees and should idle between 143 and 150 or so in the lake. The black tarry substance is residual unburned fuel, oil. Pretty common. Worse if the powerhead is running cold (not up to normal temps.)
 
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