Garage Full of Gas Fumes!

Oddly enough, this happened to my Speedster right after I had purchased it. Same symptoms: Garage full of fumes. Fuel in the intake. Fuel in the block. 

I never figured out what caused it. The fuel pickup should be lower than the fuel pump. The fuel pump should be lower than the carb float, etc. I was stumped.

My answer was to pull that PICT-34 and upgrade to duals.

You should just sell that thing. 

Ted

a small piece of dirt is all it takes to plug and keep the needle and seat from closing

Troy,

Did the setup have an inline fuel filter?  If so cut it in half and see whats in there.  Maybe you have crud in your fuel tank.  I have had that happen before.

This is a car with less than 3,000 miles on it and the fuel filter looks totally clean.  There was zero debris in the float bowl.  I did just fill the tank, but it was parked on a level garage floor.

At some point I will put bigger carbs on it, but I'm amazed at how strong this 1915 engine runs with these little single barrel carbs on it.

A couple more things to consider.

• It was a very hot day when I parked it just after filling the tank and the engine was very hot.  Could that have anything to do with it?  Doesn't seem like it to me, because fuel was still running out it in the morning when it was stone cold.
• It has a pressure regulator, but it is mounted at the level of the engine tin rather than higher up on the fender well where I normally see them mounted.
• It has a mechanical fuel pump, not electrical.

Troy
Most likely it is your needle/seat valve at the top of the carb. It happened to me as well. Oil was full of fuel as the gas drained down into bottom of the engine. I replaced it and was good to go ( about a 15.00 part and a oil change of course ). I ended up adding a small gas shut off valve by the tank to turn off when not in use ( also a good anti-theft device ) - got it at Advanced Auto for like 5.00 in the mower section.

You can check it by taking the top off the carb and turning it upside down and blowing on the fuel line to see if it stops air from going through ( it should ). 

Sometimes they can just stick open as well - hence the gas shut off.

Another thing that can happen is a small hole in the fuel pump diaphragm caused by ethanol allowing the crankcase to fill up but normally you will have running issues with this problem.

Hope this helps

When an engine combo is slightly under-carbed that's a common characteristic; airspeed through the carbs, manifolds and head passages will be fast enough to hold the fuel in suspension (and make the most from a full combustion chamber burn) right from idle on up, which can be a problem in an engine set up with a higher powerband. The VW aircooled engine, being a comparatively small powerplant, is more sensitive to combination mis-matches than a bigger V6 or 8. The inherent torque of a 2 liter or bigger displacement engine (even a screamer set up to run to 7 or 7500rpm) will somewhat hide the "bottom end sogginess" that a smaller stock stroke 1600, 1776 or even 1835 will have when able to make power in the same rpm range.

Displacement is everything here; even a 1915 (330cc's larger) will feel different than a similarly set up 1600, and why I (and others) are constantly trying to talk people into building as big as possible. An > 2 liter (even when equipped to rev fairly high) just has more low end/midrange (where we spend 95 or 98% of our driving time) than a smaller engine and it makes these cars just that much more fun! 

Do you know what cam is in it, valve sizes and if any porting work and when in 3rd gear, at what rpm's does the power peak? I'm trying here to figure out the limit of those carbs (and whether they're at or past their limit) on your 1915...

It doesn't take a very big speck of dirt/crud to hold open or cause a needle/seat to stick, so I'm betting on that being the cause. How old are the fuel hoses? I realize the car doesn't have much mileage on it, but with the presence of alcohol in our gas (and we can't separate it out; what a waste!) for the foreseeable future (and how quickly it degrades rubber based fuel lines) we really should be looking for a practical alternative. New cars haven't used rubber fuel hose for what, 10 years? (or more) for this reason. There are fairly low cost options out there.

Since you just filled it, is there a vent tube and is it clogged? I wonder if the gas could seep back to the carb?

Troy---you said you had jsut filled it and it was a very hot day. I wonder if the fuel expanded and the pressure went to the carbs forcing more fuel in there while it was sitting.  Is your fuel tank overflow plugged up?

Damned PITA for sure though.  Jeez--always something, isn't it?  Hope you get it squared away.

No, the overflow vent is not plugged.  It's all back together now and I'll be driving it today, so we will see what happens.  The only real changes I made were:

• Adjusted the float slightly to be sure it closed completely, but it already appeared to be closing completely.
• Found that the fuel pressure regulator was set at 1 (it might have even been below 1) and raised it to 2.  Doesn't make sense I know, but most of the ones I have seen are set to 3.  I don't know what it should be.

I'll be watching it closely.

Troy,  did you give any thought to the suggestion of installing the manual fuel shut off valve?

$5 inline shutoff valve=peace of mind+stops the guessing.

Troy.....  Without a gauge you don't know what the pressure is....  An indication number on an adjustment dial is for reference only....  Different regulator makers or different models = different numbers for the same pressure...

Its a quick test any competent garage can do quickly....   Hope you find the problem quickly...

Full tank so high pressure head, piece of dirt in the seat, tank is higher than carb.  Instant siphon.

^ bingo

everyone is missing the point!!!   Thank God Troy gave up smoking years ago!! 

Appreciate what you are saying, but

• the tank is vented so there is no pressure.
• this is a turn key Vintage and the tank and carbs are oriented essentially the same in all of them or this would be a lot more common of a problem.
• very possibly dirt, but I didn't see anything when I opened it.

I believe it had something to do with how hot the engine was when I parked it. It was a very hot day and this engine runs VERY hot, which is a problem I will be working on. The gauge gets up to the little square at the top of the line, which is far hotter than it should be.

It was 104 today in Fresno and the car got up to its typical high temperature, but I didn't have any fuel leaks today.  I have an infrared digital temp meter and the temp of the block at the seam was 200 degrees and 220 near the oil pump.  I have no idea what it should be.

These wimpy little Empi carbs will soon be replaced by some 40IDF Webers, but until then I'll be keeping a close eye on it.

Those empi carbs are crap! Never less whether you have those or single throat weber ict or kadrons, neither carb likes fuel pressure above 1.5 lbs.

The vent hose depending how it is routed can hold fuel when you have a full tank. Example: making turns and the fuel gets up into the vent hose and then the tank cannot vent itself and the heat of the day causes the fuel to expand. Therefore your fuel system becomes pressurized. 

Another cause can be the heat within the engine compartment. On hot days I suggest opening your deck lid when you park. 

if you have an electric pump it's always good to shut the pump off before turning the engine off. Therefore there is no pressure in the lines.

if you go to a idf weber the fuel pressure is very important. Some mechanical pumps put out under 3 lbs and some as high as 6.the higher pressure causes issues with the float level. 

I've seen the same pressures with a mechanical pump. Without a gauge, you're whistling Dixie Troy. Buy one or borrow one, and get a stack of ten gaskets. Lose the regulator and set the pressure the old-fashioned way. 1.5 psi is good, anything higher can overwhelm the float valve on those carbs. Same for Kadrons and Solexes. Webers/Dellortos: 3 psi is the sweet spot, no higher than 3.5 EVER!

OK.  Here is my plan.

• Replace the carbs with 40IDF Webers
• Replace the mechanical fuel pump with an electric fuel pump
• Install an electric fuel shutoff valve
• Wire the shutoff valve and the coil +12 volt wire to a kill switch hidden in the cab. That will provide both theft prevention and eliminate the possibility of fuel flowing from the tank to the carbs.
• Measure and regulate the fuel pressure to 1.5 psi.

In addition to all of that, I need to solve the overheating problem.  Hopefully the new carbs will help, but I'll probably also install an external oil cooler.

What still puzzles me is why does this 1915 overheat and the dozen or so other exact same engines I've had, with similarly low mileage, not overheat???

Check for the "Jack Crosby Syndrome", which is an errant rag that got stuck in the fan.  Your airflow may be blocked.  Or I suppose your temp sensor could be faulty.

Several reasons why.....cam, compression, cool air in the engine compartment. If your relying on the deck lid for fresh air....it's not enough. Before carbs I would focus on your cooling issue. Remote cooler (don't mount it on the panel above the trans and behind your seat). Mount where you get air flow and where the hot air doesn't go in the engine compartment. If your case is not full flowed this is a mute point. 

Don't use one of those empi or CB inlet and outlet pumps because they are too restrictive. Also your timing should not be more than 30 total advance. 

You might also check to see if there are air vanes installed, if there is a thermostat bellows and whether it is actually working (they tend to crack in the folds and no longer work correctly) or if something is binding in the air vane actuation To prevent them from operating.  

1915's aren't that big and shouldn't over heat so I think you have something fundamental going on there.  

Troy, if you change to IDfs you need 3 pounds of fuel pressure.

You're right too Gordon, maybe those carbs are jetted for a smaller engine and a lean condition is driving the temperature up?

Hello Troy, I was in the same boat as you and it drove me nuts and I followed all the above advice and everything was working in the cooling system.The solution for me was to finally install a Mesa oil cooler with fan on the backside of the passenger wheel well, cut three large holes in the well and the fan blows the hot air out into the air stream as the car is moving.

My 911 has a mechanical oil thermostat which controls flow to the front cooler and works perfectly so I set up the speedy the same way. The Mesa cooler comes with a thermo fan switch which works great but I wanted the primary to be mechanical which the oil control vale does.

I'm running: 1915,full flowed,dual 40 Dells with pressure regulator and gauges,all the proper duct and heat control (VW),externally mounted oil filter.

I live in the South and the car runs around 200-210 degrees in 94 degree heat which I try to avoid for comfort reasons.

This took me awhile to sort as I was reluctant to mount the external cooler.

At some point I would like to replace all lines with braided. I found a piece of heavy corrugated plastic from a heater tube I had cut and that slips right over my external oil filter to protect it from road debris.

Good luck

Thanks Mike.  I'm not real clear on what your fan is doing.  Is it pulling the air out of the engine compartment through the oil cooler and then venting it to the wheel well?  If that is the case, it doesn't make sense to me to pull the hot air out and pass it through the cooler where you want cool air to cool the oil.  I'm sure I'm missing something, but if that is the case, wouldn't it be better to just put a fan over those holes and put the cooler somewhere else where it will get cool air? 

Troy, the fan is outside the engine compartment and is sucking air and blowing it out into the wheel well, its that large void behind the rear seat before you get to the firewall.

In the picture (blurry sorry) , the red,blue and green wires you see run to the relay to drive the fan and this relay is mounted on the firewall. The engine was out of the car when I took the photo.

Sorry for being so dense Mike, but I still don't get it.  Are we talking about the fan mounted to the oil cooler or a different fan?  If it's the one on the oil cooler you would be sucking hot engine compartment air across the cooler fins and that doesn't seem like a very good way to cool engine oil to me.  I know I must be missing something here.

No problem, looking at the last picture everything to the left of the firewall is enclosed engine compartment which with the engine installed and all the tin in place leaves the fan and cooler outside this space. The white area to the left in that picture is looking up and out through the engine lid which was removed at the time.

All the air moving through that cooler is coming from outside the car and the only time engine heat (from exhaust) would be sitting at idle. As long as the car is moving air is moving past this space.

On my CMC there is an opening in the shock area to this space from the outside  and I'm going make or buy some kind of cowl vent to direct more air ie. , another project.

Hope this makes sense, if not,more pictures might be in order.

Michael