71 evinrude big twin cooling

[osteospurnum]

I have recently bought a dory with a 1971 40 hp Evinrude Big Twin. I have sent off for a manual but what with Christmas it will propably be sometime before I see it<br /><br /> My query is that when the engine is started there is no evidence of the cooling water being ejected above the water line is this normal? I haven't run it long enough to find out if it over heats for fear of the possible damage.<br /> On reading through the forum it would appear that some of the older Evinrudes didnt have a pee hole and I wonder if perhaps this may apply to mine.<br /><br />Any information on this, the engine or links to other information relevant would be greatfully recieved.<br /><br />Thanks<br />Chris

 

[rickdb1boat]

Re: 71 evinrude big twin cooling

Water should come out with the exhaust relief ports at idle. With thru hub exhaust, you will not see any water from the top on that model. Look below at the pics for a '71 50 HP.<br /><br /> web page

 

[osteospurnum]

Re: 71 evinrude big twin cooling

Thanks ever so much for your reply <br /><br />Would you elaborate on some of the terms you have used <br /><br />"with the exhaust relief ports " & "With thru hub exhaust"<br /><br />Thanks<br />Chris

 

[DJ]

Re: 71 evinrude big twin cooling

Osteospurnum,<br /><br />The exhaust "relief ports" are the two holes on the top of the leg of the outboard. in other words, they face rearward and are just below the bottom engine cover.<br /><br />You will only see a steady stream when the engine is at higher rpm's. At idle, it will be spray only.<br /><br />A quick way to check for overheating is running the engine with the cowl removed. The top cylinder head should never get too hot to keep your hand on it for a few seconds.<br /><br />If you are not familiar with the last engine service interval. A water pump impeller replacement is due.<br /><br />It's relatively easy.<br /><br />Your local library may have a manual. You can copy the necessary pages until your manual arrives.

 

[rickdb1boat]

Re: 71 evinrude big twin cooling

I guess I should have stated that you will not see any water coming out of the top "Pee" hole, as there is none. It will only come visibly from the Exhaust Relief Ports, as Djohns19 mentioned, at the rear of the motor. Thru-Hub exhaust means that the exhaust from the motor is routed thru the propeller housing, underwater.

 

[osteospurnum]

Re: 71 evinrude big twin cooling

Thanks for that info much appreciated <br />Chris

 

[Lark40]

Re: 71 evinrude big twin cooling

I don't think that the 1971 model has a thru-hub exhaust. I believe that it is a shear pin design.<br />The exhaust and most cooling water exits from a wedge enclosure that hangs down behind the prop.

 

[ob]

Re: 71 evinrude big twin cooling

Lark40, I believe you are correct on the 71' 40 hp having pin drive type prop.However, a 71' 50 hp large gearcase came with thru hub exhaust.