Briggs & Stratton Blowing Smoke

[slomo]

generally if the needle fails while the tractor is sitting, fuel flows into the intake and combustion chamber and past the piston rings,

Now, i will say i repaired a Kohler CV15 a few weeks ago, gas dripping out of the muffler.... needle failed and drained the entire gas tank, and i don't know how, but i checked the oil, the oil level was perfect, not diluted and didn't smell of gas..
how it didn't get past the piston rings, i don't know. however i did change it out to err on the side of caution, and it needed it as it was pretty dark./old.

Shouldn't of changed the oil out. Probably had Amsoil 25,000 mile never change oil LOL. Loaded up with "extended drain interval technology".

slomo

 

[TylerFrankel1]

generally if the needle fails while the tractor is sitting, fuel flows into the intake and combustion chamber and past the piston rings,

Now, i will say i repaired a Kohler CV15 a few weeks ago, gas dripping out of the muffler.... needle failed and drained the entire gas tank, and i don't know how, but i checked the oil, the oil level was perfect, not diluted and didn't smell of gas..
how it didn't get past the piston rings, i don't know. however i did change it out to err on the side of caution, and it needed it as it was pretty dark./old.

The commands are actually decent motors LOL... not like those stupid "Courage" engines! I kinda wish they used the rubber seat/metal needle on these bigger carburetors like Briggs/Tecumseh used to on push mowers. They suffer from some expansion over a long period of time, but seem less prone to leaking.

 

[TylerFrankel1]

Well the Nikki in my opinion a very simple to fix carburetor. And the OP engine they came with the NIkki or Ruixing depending on date code. On the particular Nikki that is shown in the IPL you can replace the needle and seat (fuel transfer tube) all day long but if you keep using the old gaskets it will continue to fail. This particular uses an op-ring on the transfer tube that tend to be the cause of fuel leakage. I rarely replace the needle on these Nikki carbs to fix a fuel leakage issue.

Also these do o-rings on the main jet that tends to get loose causing those inexpereince repair person to lose them easily.

As for Ethanol, carburetor cleaner is just as damaging to rubber parts. Personally I run 10% Ethanol in everything here without problems. My personal mower has been the same Nikki for over fice year since it last cleaning and was just fine last week when I took it apart for a checkup.

The problem with ethanol is mostly it's tendency to attract moisture/draw water into gas. The water does the most damage. But ethanol isn't good for rubber either. Carburetor cleaner is hard on rubber, but you don't run your engine on carburetor cleaner day after day, year after year... it's introduced very briefly in the scheme of things. Given, you can run ethanol gasoline for years and not have issues, as it is diluted to 10%. But it's definitely not beneficial.

I agree, if I was in the carburetor I'd replace all the seals. I don't like those Nikkis because they have so many seals. The walboros manage to use just a rubber tip for the needle/seat, and then a sealing washer and gasket at the top/bottom of the carb bowl. A lot less to go wrong there...

 

[StarTech]

Hummm too many seals. Let's see.

Fuel transfer tube/bowl gasket and maybe replace the foam shaft seals. Rarely ever need a new needle valve or mounting gaskets. Since most Nikki uses a aluminum sealing washer for the fuel solenoid which rarely ever need to remove it don't replaced very often.

So basically all I need is the bowl gasket set and maybe the tiny o-ring(s) on the jet(s). On OP carburetor all I normally replace is the 698781 gasket. So no need to use the 796184 carb kit (52.30) when a 6.85 gasket does the complete job.

 

[charleneje]

I have the problem with a leaky carb as well on a mower I changed the head gasket on it drained almost the entire tank but mainly out on the floor.
To check for the head gasket I found that taking the dipstick out while running if the head gasket is blown air mixed with oil will spray out of the dipstick tube you also get smoke coming out of the exhaust and rough running.

 

[Scrubcadet10]

needle failed in the carb

 

[Kremhaus]

I had same problem on Kohler Engine and also Briggs and Stratton. Those engines are notorious for drawing fuel into the oil crankcase when idle. Mine drew so much fuel the oil level was well over the maximum and the engine backfired constantly and was blowing oil and smoke. Install an aftermarket petcock on the fuel line and shut off after use

 

[cboyette2232]

I put a new B&S engine (INTEK 17.5 HP - Model 31R907-0006-G1) on my Snapper riding mower 3 years ago. All running great until today when it started BLOWING SMOKE..... a lot of smoke. Pulled the oil dip stick and smelled of gas. Changed the oil and blew a small amount of smoke on first start. Second start had no smoke and runs smooth. Any advice on what's going on here. Here's a link to a You Tube 20 second video showing what's happening:

watch it like a hawk now that youve run it with gasoline in the oil. It may have affected the main bearing seals etc. Mine did this and one day, it got noisy suddenly and it was all over.

 

[rutbuster1]

I've seen this many times... I believe your issue is a failed needle/seat valve in the carburetor. This valve regulates gas flow into the float bowl. The needle tip is made of rubber and if it becomes at all distorted it will allow gas to flow into the carburetor and overflow it. The overflowing gas travels from the carburetor into the engine and cylinder head. It then slips past the piston rings and fills up the crankcase where the oil is with gas. That's why you smelled gas. This raises the level of oil way too high as it is diluted with gas to the point where basically a 50/50 oil gas mix is seeping into the combustion chamber and other places it doesn't belong when the engine is running. That immense amount of oil burning causes smoke. If you change the oil, voila, that gas is gone from the oil and it's back at the right level, so the smoke will stop. However, it will happen again if you don't address the carburetor. Either replace the needle/seat, replace the carburetor, or install an in-line fuel shut off valve that you shut off when you aren't using it. I'd start by using a shut-off valve and seeing if that solves the problem. Cheap, quick, easy and if that doesn't solve it no harm done. If it does work and if you're comfortable with it leave it that way. Otherwise, replace the carburetor or needle/seat.

This is probably happening because of the crappy ethanol gas we're forced to use nowadays combined with Briggs having awful QC as of late. And I imagine you may have let this thing sit with gas over the winter which can exacerbate those factors.

I agree with your reply. I've put fuel cut off valves on all of my equipment and go as far as cutting the fuel valve off and letting the engine run all the fuel out of the carb till it stalls when I'm done. Since I've been doing that, I've had no carb issues whatsoever. This ethanol gas is garbage.

 

[enginemagician]

Blown head gasket. Common thing on those Inteks. Or oil level way too high. That is definitely burning oil.

Not a carb issue at all. Not with all that smoke.

slomo

When they fail with gas/oil mixture like they described the smoke billows out like a freight train.