Thermostat

brian3127

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Jun 10, 2007
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Finishing up putting the engine back together.
Serial number 4920382
What temp thermostat is recommended
 

Fun Times

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Most likely a 140 or 143 degree temp…

In your case though the serial number isn’t enough to help locate your exact engine model due to the age of the serial number/engine year while performing a full computer search.

To help local your engine parts, we’d/you’ll need the engine model type, year, HP and serial number too to get a better idea of what parts to use on your exact Mercruiser set-up.
 

achris

More fish than mountain goat
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Most likely a 140 or 143 degree temp…

In your case though the serial number isn’t enough to help locate your exact engine model due to the age of the serial number/engine year while performing a full computer search.

To help local your engine parts, we’d/you’ll need the engine model type, year, HP and serial number too to get a better idea of what parts to use on your exact Mercruiser set-up.

It's a 1978 140hp...
 

j cat

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Finishing up putting the engine back together.
Serial number 4920382
What temp thermostat is recommended
your engine is on my mercrusier manual 143F ....many mercrusier Engines open cooling .. Serial number 4920382 ...... engines use the same T stat ..
my 470 engine has a closed cooling system 160F T stat.
 

brian3127

Chief Petty Officer
Joined
Jun 10, 2007
Messages
510
Most likely a 140 or 143 degree temp…

In your case though the serial number isn’t enough to help locate your exact engine model due to the age of the serial number/engine year while performing a full computer search.

To help local your engine parts, we’d/you’ll need the engine model type, year, HP and serial number too to get a better idea of what parts to use on your exact Mercruiser set-up.
Mercruiser 3.0 140hp
 

j cat

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Mercruiser 3.0 140hp
your serial # is on my OEM mercrusier manual Engine Serial number 4920382..
point gap .022 dwell 31-34 deg spark plug ac-mr43-t or champion rbl-8 gap .035 idle rpm 650-700 timing 6deg BTDC at idle ..................oil 4qts .
your carb should be 2GC # 7043/7044 [182/184]
carb float level 5/8in float drop 1-7/8in idle mixture setting 1-1/4 turn
 

brian3127

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Messages
510
your serial # is on my OEM mercrusier manual Engine Serial number 4920382..
point gap .022 dwell 31-34 deg spark plug ac-mr43-t or champion rbl-8 gap .035 idle rpm 650-700 timing 6deg BTDC at idle ..................oil 4qts .
your carb should be 2GC # 7043/7044 [182/184]
carb float level 5/8in float drop 1-7/8in idle mixture setting 1-1/4 turn
I don’t have points
It was changed over before I bought it
Thanks for the info
 

achris

More fish than mountain goat
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Messages
27,468
Electronic ignition
Yes, I got that. I'm asking to ensure it's SAE-J1701 rated.
What sort of 'electronic'? The complete distributor, or something like a Pertronic points eliminator?

Chris.....
 

j cat

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I don’t have points
It was changed over before I bought it
Thanks for the info
I did the change on the up date of ignition points, I install a electronic ignition pertronix 1146a . probably 25 yrs ago .
my engine increases higher power . less gasoline ..
 

brian3127

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Yes, I got that. I'm asking to ensure it's SAE-J1701 rated.
What sort of 'electronic'? The complete distributor, or something like a Pertronic points eliminator?

Chris.....
good question. there is an ignition module on the distributor looks just like a car setup. I don't know what the numbers are on it. The boat is still in it's winter cocoon.
 

j cat

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good question. there is an ignition module on the distributor looks just like a car setup. I don't know what the numbers are on it. The boat is still in it's winter cocoon.
your 140hp merc 1978 yr the distributor is a pertronix 1146A ..electronic ignition conversion kit ..to change the points.
https://www.go2marine.com/Electronic-Ignition-Conversion-Kit-Delco-4-Cyl-1146A ... I did not change the ignition coil . see if the distributor cap removes it and look up the pertronix ignitor ..may change the points..
 

achris

More fish than mountain goat
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your 140hp merc 1978 yr the distributor is a pertronix 1146A ..electronic ignition conversion kit ..to change the points.
https://www.go2marine.com/Electronic-Ignition-Conversion-Kit-Delco-4-Cyl-1146A ... I did not change the ignition coil . see if the distributor cap removes it and look up the pertronix ignitor ..may change the points..
If the distributor has a module on the outside (as stated by the owner) then it's not a Pertronic unit, it's something different, and probably not marine...

Chris....
 

brian3127

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brian3127

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If the distributor has a module on the outside (as stated by the owner) then it's not a Pertronic unit, it's something different, and probably not marine...

Chris....
If this isn't the correct one should I order a Pertronic unit
 

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achris

More fish than mountain goat
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Pertronic is just a points elimination module, not a complete distributor. Looking at that picture, it's difficult to really pin down...

Chris...
 

brian3127

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Messages
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Pertronic is just a points elimination module, not a complete distributor. Looking at that picture, it's difficult to really pin down...

Chris...
i forgot I had a close up pic of it on my phone
 

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