Now I'm really confused?

Belt seems fine but I'll replace it. Vacuum line between plenum and fuel pump (clear) is collapsed while running. I removed from both ends and does not alleviate the sound. Still it is collapsed could it have dammaged the fuel pump?. Drives are new XR's with Two inch Shorty Sportmaster lowers (drive oil fine and 2hrs old ) did not make the sound first day back out. Gimbles are in perfect working order.

Andy ..checked for potato.......nothing. However I did find that check I owe you for my new security system......I think I'll keep it!


The noise rises slightly while spinning up, but is it very slight.


Thanks for all your help guys.


Maximus

line from mechanical pump is to keep fuel contained in the case of a diaphragm rupture. If the hose is routed to a vacuum source, it will indeed collapse. My lines (carb motors) are routed above the throttle plates (not a vacuum source). Wouldn't think your hoses are an issue.

You mentioned the noise takes a couple of seconds to go away at shutoff. If the noise continues after all rotation has stopped, then it will not turn out to be gear noise, or any other driveline noise. Belt noise can continue until the rotation is completely stopped, but not afterwards.

You have a high pressure regulator on the fuel rail(s) that bypasses fuel back to the high pressure pump. Get a stethescope and rule out that puppy before you start spending money.

m

Mcolliston -
It is not a mechanical sound. And your hypothisis seems to make the most sense.

I'll give it a shot , however I'm not looking forward to sticking a stethscope up to that sound.

Maximus

Was the wife/girlfriend on board at the time?

That's what I need humor!!!!! I just picked up two Brand new Water pump Kits and a belt ....grabbing my wrenches and going to work....

Maximus

Stethascope thing worked ! The reason I couldn't place the sound was it was centered under the plenum. Some type of PCV valve/vacuum thing w / an AC Delco part # CV-856-C Valve was whistling so friggin loud!!!

Is it worth calling warranty over or will NAPA have it for 1.99

Maximus

Ouch, dont you hate spending money on things you dont need.

I have cleaned mine before and free'd them up until I could get another. Just a suggestion.

Congrats, I would have bet money it was the gear whine from the XR's but cool.

Go to a GM dealer and buy a quality part. You get what you pay for at the parts warehouses.

Yay!

Your local Mercruiser man might have only charged you $26.95 for it after replacing half of the nonwarranteed electronic doodads first (also on your dime).