View Full Version : mystery goo - anyone seen this before?

01-16-2007, 01:02 AM
Here's the story:

TR engine in a Morgan, recently restored. Tank was drained and re-filled, but not flushed. Grrr. Carbs rebuilt, new pump.

Throttle gets progressively "sticky". Pulled cable off of carbs, throttle shaft hard to turn. Pulled carbs and found this muck.

Anyone know what this is? Don;t want it to happen again.

Incidentally, the substance made it only to the intake ports. No traces in the combustion chamber (I love my $22 harbor freight borescope!), on the plugs, or in the exhaust manifold.

It's not indian head gasket sealer. (was suggested)
I doubt it was gas. (we took a 1/2 gallon sample and carefully boiled it off in a steel bowl)
Maybe from using ATF as carb damper fluid?
https://i62.photobucket.com/albums/h110/schne92650/PICT0027.jpg https://i62.photobucket.com/albums/h110/schne92650/PICT0009.jpg https://i62.photobucket.com/albums/h110/schne92650/PICT0004.jpg https://i62.photobucket.com/albums/h110/schne92650/PICT0018.jpg

01-16-2007, 04:45 AM
I was almost gonna say someone dropped some sugar in your gas tank.

01-16-2007, 06:16 AM
When you flushed the tank were the fuel lines cleaned/new?
My only guess, eliminating any unususal foreign material, would be old gas that has varnished/laquered and been 'freed' by new fuel. Does it smell like varnish? Unstabalized fuel smells just like that.
Was the tank relined/restored by a PO? I've only seen relined tanks fail by peeling/flaking but it's a thought.

01-16-2007, 07:45 AM
2 possibilities.
it could be the rubber hoses in the fuel system breaking down and turning the fuel into goo by the time it gets to the carb, but not likley from the amount there.
It's possible that the air cleaners are the "oil bath" type. and the incoming air is pulling old gooey oil through the elements and into the intake.
It be helpful to know if that goo is all the way through the carbs, or does it begin after the jets? That could be a big clue.

01-16-2007, 08:47 AM
My TR6 sat in the AZ sun for several years. The black that you are seeing had turned to a solid tar. You are looking at very old gasoline.

01-16-2007, 12:36 PM
My TR6 sat in the AZ sun for several years. The black that you are seeing had turned to a solid tar. You are looking at very old gasoline.
I think I agree with Doug....this stuff gets nasty. I had a '52 Merc tank sent out for cleaning in the late 90's...the car was parked with several gallons of gas in it in 1972.

It took FOUR DAYS in the hot tank to get the tank cleaned. The shop told me there was over one inch of varnish in the bottom of the tank.

You can try to clean it at home by soaking it with laquer thinner and then use a hot water pressure washer to try to clean it. Or have a radiator shop clean it.

Either way it's a mess...

01-16-2007, 01:25 PM
Does it smell terrible? That's what gas will do.

01-16-2007, 02:18 PM
DON'T try to clean this mess out yourself unless your a safe worker. That crap is still hazardous

01-16-2007, 05:47 PM
My bike sat for two years and
the twin carbs looked all black
and tar just like the photo. Old,
evaporated gasoline residue.


01-16-2007, 07:09 PM
normally, I would agree that it was gas.

But this happened within 4 weeks of rebuilding the carbs!!!!!

The rebuilt carbs had less than 100 miles on them!!!!

My first thought was sugar, but it turns out that's a myth.

It wasn't so much beyond the jets as it was beyond the throttle plate. The carbs were mostly unaffected except fot the throttle plate and the intake. The fuel bowls and jet assemblies were clean.

Incidentally, no PCV system on this car, either.

It cleaned up with laquer thinner. Carb cleaner worked, but not as quickly.

01-16-2007, 07:44 PM
look inside the tank....give us a full report...

01-16-2007, 08:52 PM
The stuff on the throttle plate looks a lot like OO-Mower grease a thick syrupy liquid grease we use in mower gear cases which contains molybdenum disulfide. In other words it isn't coming off easily. Excellent rust inhibiter and prevention material but what it's doing in your intake is beyond me. Someone messing with you and put it in the intake prior to install?

01-16-2007, 09:13 PM
You do NOT have sugar, it is a myth !! it simply wont dissolve in gas. You most certainly have some former gas that has turned into the nastiest crud on earth. I once had a tank that took 3 days for this stuff to drain out with the drain plug out.Later I rinsed with acetone and some clean bolts(for added impact) This took several trys to get it all!!
MD(mad dog)

01-16-2007, 11:44 PM
.........IT looks like COSMOLENE to Me!!....Next question is WHY!! trying to preserve something?

01-17-2007, 06:37 AM
Ah, I recognize this stuff. It's varnished gas.

It's really common like this in engines that are stored for a long time, but fairly routinely started and run for just a few minutes. Owners that want to "keep it lubed" are the cause. Splashes stale gas all over the walls, doesn't get things hot enough to burn it off, and layer upon layer gets built up.

Eventually the engine won't run any more, but the owner will continue to crank it over sporatically, continuing the coating process. Old motorcycles with kick starters are full of this stuff.

01-17-2007, 07:02 AM
Thanks all for the help.

So it sounds like prevention in the future is to drive the thing. Darn.

John Loftus
01-17-2007, 05:41 PM
Looks like you will need to clean out the entire fuel system. I've used Marine Clean from Por 15 (or Moss) on a tank and it worked well although my problem was dryed flakes of varnish .. not goo. But the Marine Clean is strong stuff and used as directed should get rid of the mystery goo. If you store the car with gas you need to use some gas stabilizer such as STA-BIL which is supposed to work up to 2 years.

Hirsch Automotive Products also sells gas tank cleaners, sealers, and fuel stabilizers. I've only first hand experience with their fuel tank sealer and engine paints but so far so good.