Loud Hissing Sound From Carb

[Hallett19]

Speaking of carbs in the previous thread, it got me wondering about something my carb does. I had Ty (Hotcrusader76) rebuild it, I have not seen or heard from him for a while so I was wondering if anyone could help me with it.
Around a certain RPM, I'm assuming right before the secondaries open completley (maybe 3500 RPM) it makes a LOUD LOUD LOUD hissing sound. At wide open and under 3500 it doesnt make the sound at all. If kept around 3500 RPM, it will hiss all day long so its hard to keep it around that rpm, which is a good cruising rpm for my boat (conveniently enough)
One more thing, it make it under accel and decel.

[78Eliminator]

I can't remember. Did you have an air cleaner on that, velocity stack? What?

[Hallett19]

What up Justin !! How is errrthang ? You still have the delaminator ?
I just have a Rex Marine flame arrestor deal on there, it does it with the thing on or off.

[78Eliminator]

What up Justin !! How is errrthang ? You still have the delaminator ?
I just have a Rex Marine flame arrestor deal on there, it does it with the thing on or off.
Maybe try a K&N to see if it quiets it down. No delaminator, no schiada at the moment. Whatchu been up to?
By the way, you can always call up Ty (http://www.tpcracing.com/History.html) and ask him why it's making noise. Apparently, he is building motors and pretty proud of himself. Here is my favorite quote: "....a quality assurance program that parallels some of the best NASCAR engine builders."

[roostwear]

Need details. Single/double pumper, vac secondaries, size?

[Schiada76]

Maybe try a K&N to see if it quiets it down. No delaminator, no schiada at the moment. Whatchu been up to?
By the way, you can always call up Ty (http://www.tpcracing.com/History.html) and ask him why it's making noise. Apparently, he is building motors and pretty proud of himself. Here is my favorite quote: "....a quality assurance program that parallels some of the best NASCAR engine builders."
BBBBBBBBBBWWWWWWWWWWWWWWAAAAAAAAAAAAAAHAHAHAHAHAHA HAHAHAHAHA!!!!! :D

[HammerDown]

My wire mesh flame arrestor causes that noise at WOT. Kind of sounds like a turbine :rollside:

[Hallett19]

Holley 780, 4 Barrel, vac secondary. It doesnt make the noise at WOT though....

[MikeF]

Maybe try a K&N to see if it quiets it down. No delaminator, no schiada at the moment. Whatchu been up to?
By the way, you can always call up Ty (http://www.tpcracing.com/History.html) and ask him why it's making noise. Apparently, he is building motors and pretty proud of himself. Here is my favorite quote: "....a quality assurance program that parallels some of the best NASCAR engine builders."
You could try here (http://www.tliracing.com/) too. :skull:

[roostwear]

Try this. Take the retaining clip off the secondary diaphragm shaft, disconnect it, and go run it. I'll bet your noise is gone. :D Contrary to what was written in a magazine recently, I was schooled that vacuum secondaries open when a load is placed on the engine (not an effect of just RPM) and the vacuum increases. What I suspect is your secondaries are just starting to crack open creating the noise. Remember, jets are like dynos.... the faster you go (more rpm) the more load on the engine (vacuum to the diaphragm). If this is indeed causing the problem you may be able to take care of it 2 ways. Change the secondary spring to change the opening point, or take the carb off and turn the secondary throttle blade stop in just a hair. Obviously you would need to reset your idle mixture after changing the secondary stop.
My .02.... or not.

[xs ultra]

Speaking of carbs in the previous thread, it got me wondering about something my carb does. I had Ty (Hotcrusader76) rebuild it, I have not seen or heard from him for a while so I was wondering if anyone could help me with it.
Around a certain RPM, I'm assuming right before the secondaries open completley (maybe 3500 RPM) it makes a LOUD LOUD LOUD hissing sound. At wide open and under 3500 it doesnt make the sound at all. If kept around 3500 RPM, it will hiss all day long so its hard to keep it around that rpm, which is a good cruising rpm for my boat (conveniently enough)
One more thing, it make it under accel and decel.
I have the same sound! Not sure if it good or bad.Boat runs very good.
so I'm not too concerned, but also like to know what's up with it.

[78Eliminator]

You could try here (http://www.tliracing.com/) too. :skull:
I know where I am going to get my next nascar engine machined.....NOT
:rollside:

[Schiada76]

I know where I am going to get my next nascar engine machined.....NOT
:rollside:
Maybe he sends them out like his carbs. You rework them yourself for several hours, send 'em back to him two or three times, then he offers to send them across the country to someone else that can fix them. :220v: :crossx: :D

[Ultra Compulsive]

hee hee...I think its called vacuum....dunnoo....

[Hallett19]

hee hee...I think its called vacuum....dunnoo....
I think you are right :)
Its just weird, the sound is pretty loud and people that sit near the motor are covering their ears when I'm cruising.

[roostwear]

"Sucks" don't it? :D Try the test I described... I think you'll be find the prob

[jimthetoolman]

I had a loud hiss sound and it was coming from a blown tunnel ram gasket. Do you have a tunnel ram? Not the carb gasket but the one that holds the top section of the tunnel ram.

[revndave]

My vac secondaries made a hissing noise when they would open on my old boat.