Ever did this?

I got this 18hp briggs (Intek) It's running a little rough, so I do a little tune up. New plug, air filter and clean out the carb. Crank it up, and it's running extremely rich. So, I take the carb apart against, clean it out again, wire all the little holes. Put in a new needle, and gasket. Crank it back up and same thing.
So, I spray some WD around all the places that might leak air into the carb. No change in the idle.

Take it apart again, to make sure I got the gasket on their right, and the O ring in place. Everything looks fine and dandy. But put all back together, and get the same results.
Considering there are no real moving parts inside the carb (with the exception of the needle, float and the butterflies), can a carb just give up?
I usually don't buy a new one, unless there's a good reason for it. Like rust, or too much gummed up.
But this one was pretty clean when I took it apart. Extremely clean when I put it back together, like 4 times.

Is it a Nikki or a Walbro,
Running rich is either going to be too much fuel or not enough air
Not enough air = choke hooked up wrong , sticking or choke return spring broken
Too much fuel = missing main jet, main jet enlarged because of excessive force during cleaning or float level too high.

did you check that the float cuts off the fuel before it gets to the end of its travel ?

Are you sure it is running rich ?
a slightly retarded spark will also exhibit similar symptoms to a rich mixture.

It's a nikki.

It seemed to run better when I closed the fuel valve about 1/2 way. Then when it started to sputter real bad, I could choke it some, and it would pick up. But all those little adjustments, were only temporary.

I found some new ones on Ebay for like $25. I'm gonna take this one apart once more. and get it under the magnifier. If I can't see anything, I'll junk it.

I was just wondering if anyone else ever had one that just wouldn't act right, no matter what.

Some of those Nikki carbs have a main jet that us held in by the friction fit of an O-ring.
The O-ring hardens with age (and ethanol gas) and may fall out when the bowl is removed from the carb.
The jet is usually difficult to find if dropped: they seek out the black holes in your shop floor......

that would definitely cause a rich condition.

Ronno6 said:

Some of those Nikki carbs have a main jet that us held in by the friction fit of an O-ring.
The O-ring hardens with age (and ethanol gas) and may fall out when the bowl is removed from the carb.
The jet is usually difficult to find if dropped: they seek out the black holes in your shop floor......

that would definitely cause a rich condition.

Click to expand...

Upon further inspection, I did notice that O ring that slips onto the bowl housing (on the bottom) was wore pretty bad. I think I've got a kit for this carb somewhere. Just gotta find it. I think I robbed the needle out of it.

I have been trying to find a bulk source for those jets.
Way too many pull the plastic off stick their air hose on the end of it and "blow it clean", thus consigning their main jet to that far away parallel universe inhabited by all the lost car keys and left socks.

bertsmobile1 said:

I have been trying to find a bulk source for those jets.
Way too many pull the plastic off stick their air hose on the end of it and "blow it clean", thus consigning their main jet to that far away parallel universe inhabited by all the lost car keys and left socks.

Click to expand...

I accidentally shot a tiny spring across the shop one day. One from a weed eater, I think. Anyways. looked for 15 minutes and gave up. Everyone once in a while, when I was in that area, I'd sort of glance around for it. But nothing.

Finally, a month later, I'm moving an old craftsman mower around, and just happened to look down on top of the front axle, and low n behold, there it lay. It never hit the ground.

Funny thing about it, those front axles have a high spot in the middle. No little valley's or sunken spots.