riverone

Have a 502 engine with a 4 barrell carb. Boat was running fine and the last time I went to use it the engine will not idle. I can get it to idle down to 900 rpms but anything lower than that it stalls. Checked the fuel filter and it was ok. Where do I go from here?

BDiggity

Carbs? I've had to make adjustments to mine over the summer.

Griff

It could be a dozen or so different things. If it runs fine other than at idle, its probably in the carb.

FIXX

iTrader: (2)

Remove flame arrestor and see if theirs any fuel dumping out the j tubes..may have a piece of crap stuck in the needle and seat..

Unlimited jd

iTrader: (5)

sounds like a vacuum leak or the choke needs to be adjusted, did it just start this all of a sudden ? runs fine otherwise ?

Thunderstruck

Make sure:

Blades are shut on the primaries and sec.
No air leaks
stuck needle and seat (wouldn't run even at 900 rpm but check anyway)
powervalve leaking
check timing
check plugs/wires/dist cap and rotor not likely if not missing

TexomaPowerboater

How long did it sit before your last run? Was it cold weather when you started having problems? Did you let it warm up and see if you had the same problem?

900rpm idle sounds good to me.

Pismo10

If it is a QJet, it has dirt in it. They hate dirt and the idle clogs up. take the top off and clean out all those little holes.

klaw

Sea foam fixes all

bcfountain

my boat will idle between 600-900.shoot for something around there.depending on the temp and humintey the idle will change.