Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

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Dangerboy

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I have a 1978 evinrude 115 hp, how can I if its equiped with Speed Limiting Overheat Warning system (S.L.O.W).
I recently had it out in the bay and the heat gauge showed about 230f it looked to be pumping good at 4000 rpm but was pumping weak at idle, I had a new impeller put in it and just putting around at 1000rpm in a no wake zone the temp gauge showed a bit over 180. my motor does not have a ovwerheat alarm so I am concerned I amy have other issues as I am not sure of the correct opertaing temps..

Thanks
 
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Daviet

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

Without looking up your engine in a shop manual, I didn't think the SLOW system was used in the 70'S.
You should have a overheat horn in the control box, you should check it out to see why it didn't go off at 230f.
 
BonairII

BonairII

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

Dangerboy said:
I recently had it out in the bay and the heat gauge showed about 230f it looked to be pumping good at 4000 rpm but was pumping weak at idle,
Click to expand...

Pee stream can show strong, but if t-stat may be preventing water from reaching the water jackets and cooling the cylinders. The pee stream just verifies that the impeller is working...NOT that the engine is actually being cooled.

Find your overheat horn and test/fix it before running the motor again.
 
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boobie

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

Fix the overheat horn. One thing else to remember is those temp gauges are not always the most accurate.
 
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Dangerboy

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

I was told that the motor does not have a overheat alarm from the guy I got it from, He did say that if it got hot it would shut down so I am assuming he was talking about the (SLOW). I would like to install a overheat alarm but am unable to find one.
 
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Daviet

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

What's your model number, the one I looked up shows the temp sensor in the cylinder head and a horn in the control box.
 
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Dhadley

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

It does not have SLOW but it will indeed shut down if it gets hot enough. "Shut down" as in locks up, pistons will seize up if the motor gets hot enough. Get your warning horn and system fixed first.
 
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daselbee

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

I have seen guys wire their tan overheat sensor wires to the black/yellow kill line.
Overheat causes the tan wire to go to ground, and engine also kills.
 
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boobie

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Re: Speed Limiting Overheat Warning system in 1978 Evinrude 115hp ?

Good idea if you put a toggle switch in the the wires so you can make it back in when it cools down. Sounds like poor mans slow.
 
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