AQ131 dwell setting

AQ131

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Jun 6, 2022
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I have a AQ131 engine in my boat. The Volvo service manual says the dwell angle should be 62 degrees + or - 3. That seems high to me and I'm wondering if it's a mistake. Many thanks!!
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
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19,291
set the points gap at .019 then check the dwell .Most are 29-32
 

muc

"Retired" Association of Marine Technicians...
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Jul 7, 2004
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2,143
62° +/- 3° is correct for your engine with the original distributor and coil.

Dwell is the number of degrees the shaft turns while the points are closed - thus, the number goes up as the number of cylinders decreases. If you didn't have specs, the rough estimate was (360 degrees/number of cylinders) x 2/3, which yields 30 degrees for V8s, 40 degrees for 6s, and 60 degrees for 4s. So, as point gap increases, dwell decreases. Each degree change in dwell changes timing by one degree. So, check the timing after setting the point gap/dwell angle.
 

AQ131

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Jun 6, 2022
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62° +/- 3° is correct for your engine with the original distributor and coil.

Dwell is the number of degrees the shaft turns while the points are closed - thus, the number goes up as the number of cylinders decreases. If you didn't have specs, the rough estimate was (360 degrees/number of cylinders) x 2/3, which yields 30 degrees for V8s, 40 degrees for 6s, and 60 degrees for 4s. So, as point gap increases, dwell decreases. Each degree change in dwell changes timing by one degree. So, check the timing after setting the point gap/dwell angle.
Thanks so much for responding and the excellent explanation. The factory manual says the contact gap should be 0.01575". Does that sound right? Many thanks!!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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49,542
yes, 0.4mm or 0.016" rough gap, then grab the dwell meter.
 

AQ131

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Jun 6, 2022
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Much appreciated. This is the first time I have reached out for help. The response has been great!!
 
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