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Once the A4 is running and warmed up I get 2 to 3 second changes in engine sound at about 10 to 15 second intervals. The sound seems to become deeper and more 'throaty'. Any ideas?
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Regulator on the alternator switching on and off, changing the load on the engine?@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4
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I agree with Ed's assessment. Do you have a voltmeter or ammeter installed? if not, can you get a voltmeter on the alternator output post while the event is occurring ?-Shawn
"Holiday" - '89 Alura 35 #109
"Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
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As a test go for a short run with the belt removed, battery fully charged. Variance goes away and you'll know for sure.Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few othersComment
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Another possibility: a sticking valve. I use a cup or two of Marvel Mystery Oil per tank of gas to prevent this on my boat.Comment
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If there is no RPM change and assuming that the boat has a waterlift exhaust could this be normal as the water batches?
Dan S/V Marian ClaireComment
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maybe going thru puberty?
sigpicjohn
'77 catalina 30 #783
the only way to be sure is to make sureComment
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