79 v4 100hp Johnson runs hot

FRYE8633

Cadet
Joined
Aug 5, 2005
Messages
7
Help,<br />Our motor runs hot in water only. When connected to hose does fine but after 15-20 minutes in water, alarm sounds and feels hot.<br />We have tried to blow out and clogs, we have changed water pump assembly and checked the hose going up from water to motor. We have also checked thermomstats, they are not there. but was told this is fine in that year and model.<br />Any suggestions.<br />I need to go fishing soon!!<br />s
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: 79 v4 100hp Johnson runs hot

My bet is that either the water pick-up tube is not seated properly or you have restrictions in the water passages. If this is a salt water motor chances are the water passages are partially blocked with crud and the deflector hoses are shot. Check your shop manual.<br /><br />When you get it to run cool put new tstat in. OMCs do not idle well without them.
 

FRYE8633

Cadet
Joined
Aug 5, 2005
Messages
7
Re: 79 v4 100hp Johnson runs hot

Hi,<br />We have manual on the way, could you tell me where the deflectors hoses are located?<br />Thanks,<br />s
 
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