Last year i did a partial rebuild to a sbc with a mild cam and did an initial break in. I know for certain it was rich when this was done. At that time i had an oil pressure of roughly 40psi at idle and 55 climbing through rpms. But today was the first time i had been in the garage in some time and things changed. I had a header leak and that was my first issue i attempted to address, then i would follow with tuning it. I believe it was still rich, it made enough smoke to run anyone out the garage and my exhaust is black enough to wipe on a canvas and make a charcoal painting. It Burned my eyes as it has done the very few times ive ran it. But after fixing the leak at the header, i peaked at the guages and my oil pressure now maintains roughly 25 at idle. Long story short, turned it off, cooled down, checked oil and it smells like gas. Any clues as to EXACTLY what happened and where i went wrong? Not sure if it matters but yes it is the original break in oil. Obviously before i run her again she will get fresh oil. But any help would be more than appreciated what to do?
A bad fuel pump dumps gas directly into the pan, but since you have a bad over-rich condition, you may be dumping gas past the rings. Start with checking the choke to see if that's stuck. Bob
Could be a bad fuel pump, As already said, But more than likely Your carb is junk and needs some attn. It is dumping too much raw gas into the motor while it is running. this happens alot with aftermarket fuel electric fuel pumps when used without a reg. And if the needle on the float is not seating good gas can drain into the motor while it is not running. Also Is it missing? as it could be a ignition issue on 1 or more non firing cylinders. I can tell you one thing, Too much gas in the oil will washout your bearings and ruin that motor. I have even seen one case where a small block chevy had so much gas in the oil it blew a valve cover completly off.
What kind of carb are you using? Was it spitting or did you have a backfire before you noticed it overfueling?
Hold the choke open while the motor is running and look in the carb with a flashlight. You'll see droplets of gas if its flooding . Also look after the motor is switched off~ it'll probably be dripping. A new needle seat and float will probably take care of that. Of course don't rev the engine while looking down the carb - and don't use the old oil for a shop heater
Ambitious1...READ the damn rules for the HAMB...INTRODUCE YOURSELF before asking questions,,,your profile also just says "Ohio" nothing more..
Obviously the guy is paniced, and he overlooked the obvious rules. I say give him a break, and PM him instead of public humiliation on a welcome. You probably have a needle and seat not closing..... Best way to tell is run the engine for 5 then shut it off, if white smoke come out of the top of the carb, or the venturis are wet then its the carb. If dry then something else. Your exhaust is tellin me the carb needs rebuilt to some extent.... Oh and by the way, Welcome.
Yeah you tell him wbrw32.. Black smoke or White smoke? Black is too rich, you may have fuel past the needle and seat. Change the oil and run it again and assess
One word of caution. While you are diagnosing the problem... your oil is thinning out. I lost a brand new 396 when rust in the gas tank kept the needle and seat from closing. The carb was just rebuilt and the floats were set correctly so I was not thinking about that. The gas in the oil wiped the cam and all the crankshaft bearings. I had the car at the shop and drove it out everyday so we could work on customer cars. It was an expensive lesson. an alarm should be going off in your head. Find out where the extra fuel is coming from and fix it before you ruin a good engine. It doesn't take long.
Ditto, fuel pump; Another thought, check the gas cap; We had a customer car with a crankcase full of gasoline,..... Gas cap vent was inop, and vapor pressure pushed fuel past the carb float, and into the cyls, past the rings. Not a common thing, but it has happened. 4TTRUK
Carb screwed up, fix it or replace it, change the oil which is contaminated with gas from the screwed up carb, that's all.
What kind of car and what carb? I used the stock Model A tank as a reserve years ago and forgot to shut off the valve one night - came out to a motor full of gas - nearly hydrauliced it. Also Edlebrock carbs need a regulator set around 5 psi max or they run rich as hell. Just a thought but it's probably like the other guys said - fuel pump (although I don't know why that would make it run rich)
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