1971 Johnson 50 Steaming at Low Throttle?

[spike440]

Hi! I have a 1971 Johnson 50hp outboard. It is on a 24' pontoon. I was out trolling at idle rpm's and after a while I noticed steam coming from the two slots on the back of the motor just below the engine cover. Usually, and at higher rpm's, water runs out of the slots.<br /><br />Are the slots supposed to have water coming out always? There is a decal right above the slots, but the lettering is worn off. All I can make out is an arrow pointing down toward the slots.<br /><br />Is this engine supposed to have a weep hole? Are these slots it? <br /><br />I appreciate any help you give as I am a complete outboard novice.<br /><br />Thanks!<br />-Spiker

 

[Joe Reeves]

Re: 1971 Johnson 50 Steaming at Low Throttle?

Spiker.... If you haven't changed the water pump in two or three years, I'd suggest you have a new water pump assy and thermostat installed on general principles.<br /><br />That engine does not have a water telltale outlet. The majority of the water is expelled out thorough the prop area. The engine is designed that if overheating is taking place, the alarm system will engage before the engine is hot enough to do any damage.<br /><br />The slots you mention are exhaust relief outlets/ports. If they were non existent the engine could not rid itself of the exhaust pressure at the low rpms which would cause the engine to die out. They are also a exit for water, should the cooling water between the outer and inner exhaust housings reach that level.<br /><br />To test your engines overheating horn warning system, turn the key to the ON position, find the tan heat sensor wire that protrudes out of the cylinder head, on that wire slide the insulating cover back and ground that knife connector to the block. The horn should sound. If it does not, find out why..... do not run the engine unless the warning system works.

 

[spike440]

Re: 1971 Johnson 50 Steaming at Low Throttle?

Thanks for the reply! I will check the wire you mentioned, but I hope the warnng horn is on the engine. The only horn on the boat I put on it. Should I wire the tan wire into the horn I installed? Is it a sign of something wrong that steam/water is coming out of those slots? Or is that normal?<br /><br />The water pump replacement is the first thing to do, but without any outboard repair places near me it looks like I will have to do it.<br /><br />The thought of pulling it apart to replace the pump assembly worries me. This is an old engine that will no doubt not want to come apart.<br /><br />Thanks again for the help! Any more wisdom you can give is greatly appreciated!<br /><br />-Spiker

 

[ledgefinder]

Re: 1971 Johnson 50 Steaming at Low Throttle?

If your keyswitch is in the control box (with the shift/throttle lever), your hot horn is there also. If the keyswitch is in the boat's dashboard, there may be just a hot light next to it or there may be a hot horn behind the dashboard. Try the test Joe Reeves described & the noise will help you find it...

 

[spike440]

Re: 1971 Johnson 50 Steaming at Low Throttle?

Well I found the wire. I pulled the rubber sleeve back and grounded the connector, no horn. <br /><br />My key goes in the control box with the throttle lever.<br /><br />I guess I have to take the control box apart now. Wish me luck.<br /><br />I called the closest outboard shop and they told me they will not work on my engine. Guess the solenoids for the hydro-electric shift are easily damaged and obsolete so they want nothing to do with it.<br /><br />This boat thing is getting to be a pain.<br />-Spiker