1970 evinrude 40 hp overheating

[nikmisko]

First off Thanks for help so far guys i got throttle connected.

Now I get the motor running and it runs for about 3 4 minutes and then starts heating up and overheats. First i thought it was the bunny ears that didn't have good connections. Now i cut a barrel and filled it up and still overheating.
I was reading through here and sound like people get this when there water pump is not working. Can someone help how to test if it is the water pump and any instructional on changing it.
Or if you think something else is wrong please let me know.

Thank you all very much for your help

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Is there a way to test the water pump?

 

[tx1961whaler]

Re: 1970 evinrude 40 hp overheating

If running in a barrel, the water must be very high up the leg in order for it to pump. Probably the impeller needs changing, as this is a maintenance item that need to be done every few years.
To change the water pump impeller, the lower unit will have to be dropped.
Please post the model number of the motor, as there are manual and electric gearcases available on a 1970 40 hp and the procedure is different for each.

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Thank you very much for your reply now i can sleep good knowing help is on the way. The model number is 40072A 40 hp 1972. Do you think i should chek the thermostat as well ?

 

[tx1961whaler]

Re: 1970 evinrude 40 hp overheating

Yes, check the thermostat. If you remove it, you should see water shooting up through the hole from the water pump when the motor is running.
That is an electric shift motor, so disconnect the shift wires and tie a long string to them. There may be a small plate on the side of the midsection that needs to be opened, as there may be a clamp under it for the shift wires. You service manual should have this detail. Remove the 4 or 5 bolts holding the lower unit to the midsection and lower it. The string will be used to pull the shift wires back up, so leave it in the midsection. The drive shaft comes out with the lower unit, so you may have to tilt the motor.
Take off the water pump housing, which is on top of the gearcase, and remove the old impeller. Put the new one on and lubricating the new one with liquid soap helps to get everything back together. The driveshaft turns clockwise when viewed from the top.

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Thanks alot TX part of the problem is that i just got the motor and i have no manual. Is there pictures or does anyone have online manual etc. Thank you very much

 

[eavega]

Re: 1970 evinrude 40 hp overheating

If you intend to keep that motor, you are probably going to be doing all the repair/maintenance yourself. you need to invest in the OEM manual. You can pick it up on eBay, or various online retailers. It pays for itself a thousand times over.

Rgds

Eric

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Here is the latest update.

I took the thrmostat out and put it above the wtove with boiling water and it opens up.
But when i ran the motor there was no a drop of water going up to the thermostat. But when i hook up the bunny ears the water leaks out the bototm peace. I am guessing it can only be the water pump.

Do you think i can get away trying to do it without the maual just from the pictures of parts? keep in mind its my first boat project ever.

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Here is the latest update.

I took the thrmostat out and put it above the stove with boiling water and it opens up.
But when i ran the motor there was not a drop of water going up to the thermostat. But when i hook up the bunny ears the water leaks out the bototm plug.

Do you think i can get away trying to do it without the maual just from the pictures of parts? keep in mind its my first boat project ever.

 

[nikmisko]

Re: 1970 evinrude 40 hp overheating

Sorry Eric didnt see your reply i am definetly looking for a service manual but so far i only found one marina with it near me and its 59.99 so i am searching around on net if anyone here has one for sale i would definatly buy it.Thanks