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#1
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hi rpm overheating
I have a motor question I have twin Mercruiser inline 4 cyclinder 3.7 LX
motors one has run fine the other however seem to begin to overheat when rpm get over 3000. these are freshwater cooled. while trying to figure this out we noticed that in the over heating motor down on the bottom when we squeeze the hoses to see if we have water moving we dont get and movement in that area its a little box with some wires coming out of it Ive been told maybe its a voltage regulator? cant really make heads or tails from the repair manual. I know this isnt much to go on but could but it seems to be the one area where we have a difference. does anyone have an idea of what Im talking about or what I may be able to do to repair this issue Thanks Paul |
#2
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I had an overheating outboard, only at high RPMs and it turned out to be
restricted water flow. That may not translate to an inboard but it is something to think about. |
#3
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pmiller wrote:
I have a motor question I have twin Mercruiser inline 4 cyclinder 3.7 LX motors one has run fine the other however seem to begin to overheat when rpm get over 3000. these are freshwater cooled. while trying to figure this out we noticed that in the over heating motor down on the bottom when we squeeze the hoses to see if we have water moving we dont get and movement in that area its a little box with some wires coming out of it Ive been told maybe its a voltage regulator? cant really make heads or tails from the repair manual. I know this isnt much to go on but could but it seems to be the one area where we have a difference. does anyone have an idea of what Im talking about or what I may be able to do to repair this issue Thanks Paul The 3.7L LX motor is based on, and the replacement for, the Mercruiser 470 engine. Later versions of the 470, and it's descendants, used salt-water cooling for the voltage regulator. On a 470 the voltage regulator is inline with the salt water inlet, from there water goes to the heat exchanger, then to the exhaust elbow. You may have a restriction in the voltage regulator. The 3.7 LX was produced from 1986-1989, does that sound like your motor? |
#4
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A bad impeller in the outdrive can cause overheating at speed.
"pmiller" wrote in message ... I have a motor question I have twin Mercruiser inline 4 cyclinder 3.7 LX motors one has run fine the other however seem to begin to overheat when rpm get over 3000. these are freshwater cooled. while trying to figure this out we noticed that in the over heating motor down on the bottom when we squeeze the hoses to see if we have water moving we dont get and movement in that area its a little box with some wires coming out of it Ive been told maybe its a voltage regulator? cant really make heads or tails from the repair manual. I know this isnt much to go on but could but it seems to be the one area where we have a difference. does anyone have an idea of what Im talking about or what I may be able to do to repair this issue Thanks Paul |
#5
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Got a manual ? Waterpump impeller?
"pmiller" wrote in message ... I have a motor question I have twin Mercruiser inline 4 cyclinder 3.7 LX motors one has run fine the other however seem to begin to overheat when rpm get over 3000. these are freshwater cooled. while trying to figure this out we noticed that in the over heating motor down on the bottom when we squeeze the hoses to see if we have water moving we dont get and movement in that area its a little box with some wires coming out of it Ive been told maybe its a voltage regulator? cant really make heads or tails from the repair manual. I know this isnt much to go on but could but it seems to be the one area where we have a difference. does anyone have an idea of what Im talking about or what I may be able to do to repair this issue Thanks Paul |
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