Gas in oil

[Randy92782]

Ok so i haven't drove my old turd (83 GMC) in awhile now so i decide to fire her up. Battery's dead so i go and buy myself a new one.

Start to crank her over and she was running rich so i tried adjusting her to no avail. still running rich. Then took the carb off my blazer and threw it on. STILL running rich even with this carb. Then all of a sudden my stepdad says to SHUT IT DOWN!!

For some reason it started shooting gas/oil out of the breather tube going into the breather. It's everywhere. checked the oil and it smelled like gas and was over full.

So my question is what could cause this. Our only thoughts were that maybe the diaphram for the fuel pump is bad sending it into the oil

Never heard of this before but it's possible i guess

What say you knowledgeable gentlemen??

EDIT: BTW no vaccuum leaks or anything out of the ordinary. Checked over twice before even firing it up

 

[4X4HIGH]

There are two things that cause fuel in the oil, the first as you guessed it is a bad diaphram in the fuel pump, the other is from running too rich and the unburned fuel works it's way past the rings and into the crankcase where it mixes with the oil. There are several reasons why or how the carb can do this (float level too high and dumping fuel out the vent tube, an internal blockage in one of the passages and now allowing fuel to dump through the boosters, or a misadjusted or bad or faulty choke).

 

[ttuburbo]

How long was it sitting? Sounds like the fuel pump to me, had it happen on a 73 mustang a few years ago that had been sitting.

 

[Randy92782]

How long was it sitting? Sounds like the fuel pump to me, had it happen on a 73 mustang a few years ago that had been sitting.

bought my other truck last June i think so about that long

I started it every so oftne but it was neglected in the winter.

There are two things that cause fuel in the oil, the first as you guessed it is a bad diaphram in the fuel pump, the other is from running too rich and the unburned fuel works it's way past the rings and into the crankcase where it mixes with the oil. There are several reasons why or how the carb can do this (float level too high and dumping fuel out the vent tube, an internal blockage in one of the passages and now allowing fuel to dump through the boosters, or a misadjusted or bad or faulty choke).

It's probably a mix between everything. I may take one of the carbs apart tomorrow and see if i can see anything that may be blocked. After i change the fuel pump that is.

Also i forgot to mention that it was building up pressure in tank. when i was changing carbs i took the line off and it kept pumping fuel out. (not running at the time.) I put it back on and grabbed a can. I bet i got more than a soda bottle full out before my stepdad took the gas cap off

think maybe my return maybe clogged too?? maybe causing the problem as well. I have alot of trouble shooting to do tomorrow. Good thing we got good weather coming

 

[imiceman44]

bought my other truck last June i think so about that long

I started it every so oftne but it was neglected in the winter.



It's probably a mix between everything. I may take one of the carbs apart tomorrow and see if i can see anything that may be blocked. After i change the fuel pump that is.

Also i forgot to mention that it was building up pressure in tank. when i was changing carbs i took the line off and it kept pumping fuel out. (not running at the time.) I put it back on and grabbed a can. I bet i got more than a soda bottle full out before my stepdad took the gas cap off

think maybe my return maybe clogged too?? maybe causing the problem as well. I have alot of trouble shooting to do tomorrow. Good thing we got good weather coming

I don't think your return line is clogged if the gas tank is pressurized.
It's your tank vent that is plugged that could be a wasp nest or just dirt or dust.
That might be why your running rich.

 

[Randy92782]

I don't think your return line is clogged if the gas tank is pressurized.
It's your tank vent that is plugged that could be a wasp nest or just dirt or dust.
That might be why your running rich.

Never thought of that. I got a hangover so whenever i get outside i'll check that

 

[nsxxtreme]

Could it be that your gas cap isn't venting? The gas cap should allow air to go into the tank as you suck gas out. On a friend of mines car his tank caved in because the cap wouldn't allow any air inside. Maybe try running with he gas cap off.

 

[Randy92782]

Could it be that your gas cap isn't venting? The gas cap should allow air to go into the tank as you suck gas out. On a friend of mines car his tank caved in because the cap wouldn't allow any air inside. Maybe try running with he gas cap off.

thought about just running with it loose but that problem seems to be alright now