1971 40 hp Johnson Outboard Overheating in Neutral

[Cuck27]

I'm a novice and this is my very first"starter boat",I would appreciate your help in finding out if it is normal for this 1971 40 Hp Johnson outboard to oveheat while in neutral for approx 10 minutes. Thank you for your help

 

[Rodneys]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Well, it could be your themastat or your water pump.

 

[Cuck27]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

So,if I understand correctly, the overheating shouldn't have happened even if in neutral and propeller not running? Will check Therm. thank you

 

[kenmyfam]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Should not overheat when idling. Water pump service and stat check if they are an unknown quantity at this time. While in there make certain there is nothing restricting the flow.

 

[Cuck27]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Hi, here is what I've done so far,keeping in mind that being new at this I followed an online instruction: Replaced needle and seat in carb, installed water pump kit,replaced soloneid, checked pressure OK, checked gasket and not blown. This engine just not pumping,had at running this mornig submerged in large tub,a lot of water motion water seems to get in up to a certain point then nothing... ran, got hot and then started knocking or made a sound similir to someone tapping metal on metal.Shut it off restarted couple of hrs later, still overheating,shut it off before knocking.How do I check for "Restriction" Sorry to be a pest, was so looking forward to taking this out,I'm cluless.Thank you

 

[Rodneys]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

What Model number do you have. There is 8 different Models #'s for that year motor.
It could be your water intake screen is pluged also. Are you sure when you installed the impeller you had the impeller fine goung the right way ?
Check out this website and click the year, model, hp.

http://shop2.evinrude.com/ext/index.aspx?s1=8473bd731eb37b9dc3cbce49e4b59011

 

[Cuck27]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Here is the model as found on motor 40E71G.I will reck.to make sure I have the impeller in properly. Thank you

 

[F_R]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Some facts:

That motor does not have a thermostat

It is impossible to install a new impeller the wrong way. Old impellers should never be flipped over.

The passages through the cooling system are big enough to throw a screaming cat through. Unless it is avery salty dog, I seriously doubt it is plugged up.

So, why does it overheat??

Was the water pump housing worn? Did you clean and seal under the plate? Are the water tube grommets in good shape?

And lastly, running in a barrel is one of the chief causes of supposed water pump trouble. Did you have it deep enough in the water? And keep the water hose running in the barrel (overflowing) so the barrel water doesn't heat up.

If you got it that hot, you probably damaged the head gasket and exhaust cover gaskets, if not worse.

 

[Cuck27]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

The last thing I did this am. was to reck pressure,to identify possible damage to head gasket, pressure Ok (90), so I ruled it out....? I did run the motor in a new 30 gallon waste can with hose in it and did overflow. I did not however clean and seal under the plate,I will do that as well as recheck water tube.
How do I check for damage to exhaust cover gaskets? A friend,not a mechanic, suggested checking for hole in tubing by using an air compressor does this make any sense to you?
I'm in over my head, but couldn't find a marine that could fix it prior to my vacation which is now half way over, all booked 'til end of July....
Thank you much for your suggestions and effort.

 

[Cuck27]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral Problem Solved!

Re: 1971 40 hp Johnson Outboard Overheating in Neutral Problem Solved!

After all that.....It was a badly and completely plugged weep hole. I said I was a "Novice"....! Thank you all so very much

 

[kenmyfam]

Re: 1971 40 hp Johnson Outboard Overheating in Neutral

Glad all is now well.