Petcocks Plugged

"I boat in a shallow lake with

"I boat in a shallow lake with lots of silt and sand. I am winterizing my 1990 5.0 LX...when I opened the petcocks to drain the water, they were plugged - had to dig around with a nail quite a bit to get a flow. I did get it to flow out fast and alot of crud came with. IF I saw a good flow out of all petcocks, am I safe or is there something I should do to flush it out. HELP"

"This is normal with RWC engin

"This is normal with RWC engines. It is a buildup of scale that blocks the petcocks, just remember to rod them every year to insure that the block and manifolds are draining properly. P.S. don't forget to drain or backflush the PS cooler.

Rick"

"That's what happens when

"That's what happens when people use petcocks instead of pipe plugs! Okay, so it takes a wrench to remove the pipe plug, but the hole is full sized, right? Not so with a petcock screwed in there.

Jeff"

"My 4.3L has petcocks, brass.

"My 4.3L has petcocks, brass. If you turn the wing handle the whole valve mechanism turns out, and gives you a large discharge hole. A piece of wire helps to get any small or large sand out. I don't run much shallow, except when entering my slip when the summer water level is low.
Danger. If the pet cock is opened and doesn't drain immediately assume it is plugged and remove it and clean it. Opening the plug and letting it "drain" whicle winterizing it is dangerous. I' might be plugged and not drain, when you return you close it thinking that it has drained....cracked block/exhaust manifold.
BEAR"

"i think fred flintstone said

"i think fred flintstone said it best by saying dont touch petcocks on marine engines. flush engine with green antifreeze through the outdrive, it will protect your engine from freezing and prevent corrosion over the winter."