Itinerant Air-Cooled

So here I was, beautiful Saturday morning trying to start my recently installed with Colin's awesome help my "turn-key" engine from Headflow Masters. It has (had?) approximately 50 miles of working flawlessly, all miles on short trips to and from my home to work and back. I hadn't started it since Tuesday and the battery was dead. After re-charging it, I started turning the engine, only to get back an eerie "spin,spin,spin,... " as if the coil was disconnected or no gas was flowing into the carbs. I must have tried to get it started 3-4 times before telling myself to have a look at the engine to try and find a possible motive. After some detective work (inspector Gadget would be very disappointed in me), I saw a very small drip of oil coming down from where the back of the engine attaches to the transmission case. Immediately, I measured the oil levels and found that the dipstick came back out rather "clean". Weird was the word that came to mind, seeing that the tiny puddle of oil was not indicative of any major oil spill. In any case, a BIG disappointment was surely about to come my way. So...I decided to close the engine lid and spend the rest of the day feeling sorry for myself and my $6,000 plus engine set-up.
This afternoon, I returned to the bus, hoping to see if there was something that I had missed during the initial eval. I decided to drain the oil from the engine in order to see two things: how much oil was still left inside the engine / crankcase, and if the engine showed signs of a catastrophic engine failure by revealing metal shavings or what-not.

Surprise, surprise!!!!!!

As soon as the bolt was loose enough, the oil pan started "peeing" a watery substance along with oil! It took me a few excruciating seconds to realize it was fuel coming by the gallon along with the oil!

What say you...besides the fact that I seem to be....ucked?!

Stuck floats? So gas is flowing down the carbs into the engine.

Hmmm, interesting! Have you ever heard anything similar to what I'm describing happening before? I'm waiting for Colin to get back to me and give me some ideas as to what he thinks happened...and then what to do about it. I am really baffled by the whole ordeal.

What kind of fuel pump are you running? Electric or? I'd breathe for now. It's going to be something stupid that caused the fuel to get in the engine. You can refill it with fresh oil run it for a while then flush that oil and add new oil again. Of course, this after you determine where/how the fuel got into the crank case.

Excess fuel pressure can cause issues too.

Did the dipstick read over-full? You may get lucky and see the leak disappear when the crankcase is free of solvents…

The fuel can come from a few places. As stated above, typically the needle valves in the carbs fail to shut the fuel pump pressure off after shutdown, and fuel can overflow the carb bowls and end up in the crankcase through the intake tract after sneaking through the rings. To figure out if this is the case, you can pull the upper "plate" pieces off the carbs and inspect both bowls for fuel level. If one is lower, you have found the offender. If both are the same, try blowing through the input fuel line into each carb while you actuate the needle valve with your finger. Both valves should seal 100% and open immediately with air pressure from your mouth. Mmmmm taste good?? :)

Another option, though rare on engine rebuilds, is the mechanical fuel pump that some engines came with. You'll see it below the #1 cylinder in front of the lower tin under the car if you have it. It has a "drain" tube from the factory in case the diaphragm ruptures to prevent this from happening, but it is a possibility still.

If you have an electric pump, it would behoove your engine to do a fuel pressure test at idle and through some revving in neutral by hand. What carbs do you have? Some prefer specific pressures, others can tolerate a range.

Good luck getting all the fuel out of the crank case and getting new oil in. Like wcfvw69 said, a quick oil change and startup/oil change would help flush any remaining gas out.

Robbie

asiab3 wrote:Did the dipstick read over-full? You may get lucky and see the leak disappear when the crankcase is free of solvents…

The fuel can come from a few places. As stated above, typically the needle valves in the carbs fail to shut the fuel pump pressure off after shutdown, and fuel can overflow the carb bowls and end up in the crankcase through the intake tract after sneaking through the rings. To figure out if this is the case, you can pull the upper "plate" pieces off the carbs and inspect both bowls for fuel level. If one is lower, you have found the offender. If both are the same, try blowing through the input fuel line into each carb while you actuate the needle valve with your finger. Both valves should seal 100% and open immediately with air pressure from your mouth. Mmmmm taste good?? :)

Another option, though rare on engine rebuilds, is the mechanical fuel pump that some engines came with. You'll see it below the #1 cylinder in front of the lower tin under the car if you have it. It has a "drain" tube from the factory in case the diaphragm ruptures to prevent this from happening, but it is a possibility still.

If you have an electric pump, it would behoove your engine to do a fuel pressure test at idle and through some revving in neutral by hand. What carbs do you have? Some prefer specific pressures, others can tolerate a range.

Good luck getting all the fuel out of the crank case and getting new oil in. Like wcfvw69 said, a quick oil change and startup/oil change would help flush any remaining gas out.

Robbie

Report from PM inbox says it is running OK with very clean oil presently. If symptoms recur, we'll hear about it here.
Colin

(had to delete the philosophical wildfire that followed . . . it was a good one, but it veered)