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What the heck is this noise?
Posted: Sat Dec 24, 2016 7:06 pm
by hobo
I can't figure out what is going on here:
https://youtu.be/V9t_K7f9QeI
Noise pitch seems to fall as throttle increases. Vacuum hoses checked and all seem to check out. I would think a bearing or belt would rise in pitch with throttle. Any ideas?
Re: What the heck is this noise?
Posted: Sat Dec 24, 2016 10:38 pm
by gww
might get a couple ft. long hose, close to your ear then move around with it to locate source.
Re: What the heck is this noise?
Posted: Sun Dec 25, 2016 9:15 pm
by EGroscup
Certainly sounds like an intake leak to me. I am going to guess intake manifold gasket and/or carb mounting gasket.
Re: What the heck is this noise?
Posted: Mon Dec 26, 2016 12:19 am
by PwrWgnDrvr
When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.
Re: What the heck is this noise?
Posted: Wed Dec 28, 2016 11:26 am
by hobo
PwrWgnDrvr wrote:When throttle opens, vacuum decreases, therefore intake leak pitch goes down.
Spray starting fluid around carb base, manifold joints, etc. If it sucks in through a leak, engine rpm changes and you can thereby locate the leak.
Thanks, will check. It definitely seems to be coming from that area. I pointed a hose at all the pulleys and it didn't sound like they were culprits.
Re: What the heck is this noise?
Posted: Sat Jan 07, 2017 4:03 pm
by hobo
It was the carb mount gasket. How rare (but how lovely) it is when the fix is $3 and 10 minutes.
