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New old Volvo owner , AQ 170 vacume advance.

ctp13

New member
Yep just bought a can of worms :) no not bait....my new old boat 73 bayliner has a AQ170 there is history of someone who did not know what they were dooing took out the distributor.......before I get to re timing this , I noticed it has a vacume advance - i thought boat engines had mechanical advance , possible the distributor came out of a volvo B30? Car.

Thanks .......

oh in Sacramento ca
 
No vacuum advance on marine disti's.... which gets us to.... non marine disti's not allowed on boat engines.... USCG and insurance company will react "badly" when/if they become aware of it. and, no, you can't upgrade/convert an auto disti to a marine one. Marine one's need to be certified and tagged as such.
 
The non-marine-approved distributor with vacuum advance is still a mechanically advancing system. The vacuum advance simply adds additional ignition advance during high manifold pressure (aka coast time)!

The marine engine never sees coast time, so vacuum advance is not necessary.

As noted, the automotive ignition distributor does not meet the "ignition source protection" requirements........ AND the ignition advance curve is incorrect for marine use!


I would find and install the correct unit and set the timing as per OEM specs!


.
 
Thanks havent had a moment to look for a correct distributor - working on the house and getting closer to being done for this years work .
 
Still no time to work on boat but for everyones edification it apears that Volvo did in fact use vacume advance on some aq170 and 165 engines - not good practice by todays standards but reasuring that the engine in mine might be stock and not from a car . Pics are from Volvo AQ manual .
 

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Must be for the California surfing market ;-)

Very possibly! :D



I am surprised to see that! Even with the vacuum diaphragm advancing unit, there is no coast time (no periods of high manifold pressure) on this engine that would allow a vacuum diaphragm advance system to be of any benefit.

I would make sure that the "Mechanical" advance is working properly, and is giving your Engine the correct OEM ignition advance curve.

See the OEM curve specs.

 
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