Why no vacuum advance???
#1
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Why no vacuum advance???
I am a big fan of KISS (keep it simple stupid), but the more I read about setting up timing on a marine distributor, the more I come across people who have had problems setting the timing for a good compromise between Idle and Loaded.
A vacuum advance takes care of this. Why isn't it used?
thanks
A vacuum advance takes care of this. Why isn't it used?
thanks
#2
Re: Why no vacuum advance???
My thinking is that vacuum advance was installed to get extra advance at cruise (= gas mileage) and at idle on automobiles. Boats run with a pretty heavy load all the time, low vacuum compared to your car. All the new stuff is electronic no weights and springs to maintain. Just my 02.
#3
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Re: Why no vacuum advance???
Hook a vacuum gauge up and see what you are running. It will always be very low except at idle. Coming on plane likely has the same advance as 3800 with a vacuum advance. Too small of a vacuum range to adjust the timing with.
#4
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Re: Why no vacuum advance???
I guess that's what I was getting at. Vacuum advance would allow you to run more advance at idle (which is usually very desirable) while still keeping reasonable advance at low rpm's coming on plane. Without vacuum advance, you always end up compormising on the idle advance to avoid detonation at low rpm WOT.
Is the answer as simple as: Boaters don't care enough about idle to add another contraption?
Is the answer as simple as: Boaters don't care enough about idle to add another contraption?
#5
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Join Date: Dec 2003
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Re: Why no vacuum advance???
Originally Posted by bcarpman
I guess that's what I was getting at. Vacuum advance would allow you to run more advance at idle (which is usually very desirable) while still keeping reasonable advance at low rpm's coming on plane. Without vacuum advance, you always end up compormising on the idle advance to avoid detonation at low rpm WOT.
Is the answer as simple as: Boaters don't care enough about idle to add another contraption?
Is the answer as simple as: Boaters don't care enough about idle to add another contraption?
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