1975 4hp evinrude temp

Perchin 1

Cadet
Joined
Jan 29, 2010
Messages
12
Ok guys I put new head gasket,exhaust gasket cleaned water passages put in new inpeller and motor seems to run good-The qestion I have is are the cylinder head and plugs going to get very hot while running-The side of the block feels ok I can lay my hand on it for awhile but the head I can only put my hand on for a second-I have a cheap thermal temp gun if I hold it a couple inches away the head is anywhere from 160-190 but if I hold it within a 1/2 inch its reading high wich is over 230-The block reads around 125 all times. Ran motor for about 45min in drum and seemed ok up and down through throttle range-Do these motors run hot or what-Thanx in advance.
 

F_R

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Jul 7, 2006
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28,226
Re: 1975 4hp evinrude temp

Ok guys I put new head gasket,exhaust gasket cleaned water passages put in new inpeller and motor seems to run good-The qestion I have is are the cylinder head and plugs going to get very hot while running-The side of the block feels ok I can lay my hand on it for awhile but the head I can only put my hand on for a second-I have a cheap thermal temp gun if I hold it a couple inches away the head is anywhere from 160-190 but if I hold it within a 1/2 inch its reading high wich is over 230-The block reads around 125 all times. Ran motor for about 45min in drum and seemed ok up and down through throttle range-Do these motors run hot or what-Thanx in advance.

The worry bug must be in season. I just answered the same question concerning a 3hp. The answer is---the cylinder head is not water cooled, except for around the edges. And even there, the water circulation is not forced, but just whatever happens to flow through some holes in the gasket. Result is yes it gets pretty dang hot at you get closer to the plugs. That's just normal. Helps keep the plugs from fouling when trolling.

You didn't mention the flat plate on the side of the powerhead. That gets dang hot too. There is fire inside both of those locations.
 

Perchin 1

Cadet
Joined
Jan 29, 2010
Messages
12
Re: 1975 4hp evinrude temp

Ok thanx a bunch-getting things ready for spring as I just picked up this motor for a trolling motor and still learning-
 
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