Cooling issue-1974 40hp Johnson

[ali'i]

posting this for my neighbour,and wondering if he just got ripped off. He just bought a boat with a 1974, 40hp Johnson, 15", with electric start. When the motor is started when cold, it takes a good minute or two before any water comes out the pee hole, seller told him its thermostatically controlled, and no water will come out until its warm, which is what happens, is this normal for his motor? Thanks

 

[F_R]

Re: Cooling issue-1974 40hp Johnson

There is no thermostat in a 1974 40hp Johnson. Are you sure it is a 1974 40hp?

In fact, there is no "pee hole" as such. But it does have a large exhaust relief hole in the backside of the mid section. Water should blow out there in a heavy spray within way less than a minute after starting.

 

[steelespike]

Re: Cooling issue-1974 40hp Johnson

delete

 

[ali'i]

Re: Cooling issue-1974 40hp Johnson

by "pee hole", I just meant where the water comes, and it does spray, just takes a while, he checked model number before buying, and confirmed it is a 1974, I don't have model number handy, will check myself when he gets home,

There is no thermostat in a 1974 40hp Johnson. Are you sure it is a 1974 40hp?

In fact, there is no "pee hole" as such. But it does have a large exhaust relief hole in the backside of the mid section. Water should blow out there in a heavy spray within way less than a minute after starting.

 

[Bosunsmate]

Re: Cooling issue-1974 40hp Johnson

Sounds too long to me. Check the temperature of the head, you should be able to keep your hand on it.
Sounds like some waterpump work may be needed.
The ex owner may of being mistaken about these things, always hard to be sure if its an intentional mislead

 

[oldboat1]

Re: Cooling issue-1974 40hp Johnson

think that delay might be normal, and t.stat related. As in the prev. post, engine should not get too hot before the water starts flowing out of the leg -- shouldn't be so hot at the top of the head that you cant hold the side of your hand on it for a couple of seconds or so. I had a '64 Evinrude with a hot water choke, and the spray didn't start (and choke remained open or partly open) until the thermostat opened. There was not an overheating problem.

 

[racerone]

Re: Cooling issue-1974 40hp Johnson

Is there a thermostat on a 1974 40 HP model ???-----------------Correct information is gold.

 

[HighTrim]

Re: Cooling issue-1974 40hp Johnson

No t stat as Frank mentioned. Im thinking we are not dealing with a '74 here, by the change in flow described sounds like a thermostatically controlled motor.

Really depends on water temp. In the frigid water temps up here in Ontario in late fall or early spring, no way would my t stat open in under a minute on one of my Big Twins. So, may be normal. As you noticed, the flow out of the exhaust relief definitely changes when the stat opens. You can visually see it.

First, lets determine exactly which motor we are dealing with before throwing darts. Second, determine if it is fact overheating. An infrared thermometer is ideal, but otherwise you should be able to hold your hand on the head for a 3 count, and water should NOT sizzle when splashed on the head.

If it is a thermostatically controlled motor, with a water recirc system back down to the water pump, ensure the t stat and valve are installed or exhaust gas can backtrack down to the pump, rendering it useless. They pump water great, air not so great.

 

[racerone]

Re: Cooling issue-1974 40hp Johnson

The wee plates with model # are easy to change.--------Pictures will be the identifier here.

 

[ali'i]

Re: Cooling issue-1974 40hp Johnson

model number is...40E74S, id plate appears to be original, even has original style rivets, but without the hole, more like a little round bead on top of the rivet. will try some pics, hope they download. Thanks

 

[racerone]

Re: Cooling issue-1974 40hp Johnson

That is the 74 model and no thermostat on that.--Water should come out with the exhaust almost immediately !

 

[boobie]

Re: Cooling issue-1974 40hp Johnson

Time to check the water pump.

 

[F_R]

Re: Cooling issue-1974 40hp Johnson

yep, NO thermostat!!!! It takes a few seconds for water to go through the system and discharge. As said, almost immediately.

 

[hardwater fisherman]

Re: Cooling issue-1974 40hp Johnson

i have two 1976 40hp motors, to me appear to be the same motor as yours. mine spray water as the motor is started. it is not a heavy spray. if i increase the throttle in neutral the water flow increases along with the increased rpm. you might need to check the water pump and check for some blockages in the system. if it takes 1 or more minutes than i think you have a problem.

 

[hardwater fisherman]

Re: Cooling issue-1974 40hp Johnson

just a question is the motor being run on the water? in a barrel or on muffs? if in a barrel it is possible it is not deep enough.

 

[ali'i]

Re: Cooling issue-1974 40hp Johnson

We just did a compression test, was 110 in both and done when engine cold, and test running was in big, deep garbage can with plenty of water.

 

[TN-25]

Re: Cooling issue-1974 40hp Johnson

No thermostat on the 40 horse 1971-through, nor on the 33 that preceeded it. The 1960-70 40s had thermostats since they had a water circulation loop within the depths of the "Super Quiet" double walled lower unit. The economy 33 and the 40 when it took over as an economy motor for 1971 didn't have the water circulation loop since they essentially used the old 1955-style lower unit.

That motor is a 1974 model without a doubt. They are good, strong, simple motors. Believe it or not, 1974 was the year they finally switched those motors to an alternator from a generator. They were the very last motors to do so.

 

[gm280]

Re: Cooling issue-1974 40hp Johnson

I just finished completely rebuilding a 1976 version of this motor and they look exactly the same. And I know for fact my year model 40HP does not have any thermostat. In fact the two ('74 and '76) like identical in the pictures. So if it is take 2 minutes or longer, I'd be checking the impellor. I would change everything in the water pump system. Not very expensive to totally change everything and be done with it. Also check the grommet in the pump housing to make sure the tube leading up to the power head is good and intact and actually in the pump grommet. and you can install a pee tube system very easily too...

 

[simental]

No Title

 

[simental]

i need like shorter shape.