The Moto-Guzzi Nuovo Falcone VOC

Hi, all,

In autumn, Bossom decided to pour petrol all over the garage floor.  Since then the carb has been on the workbench till a couple of days ago, when I rebuilt it after a good clean and refitted it.

Today I took the bike off the lift, put a gallon of fuel in the tank and she started first time under choke.  She wasn’t very smooth, but I needed to adjust the carb.  Couldn’t get her to run smoothly at all, even when warm, so I thought I’d put her back on the lift and drop the oil, clean the plug and think about the timing.  After all, I keep hearing that most fuelling problems are electrical………


So I put the drain bucket under the sump and loosened the filler bolt.  Black, thin liquid smelling of petrol started to gush out (all over the exhaust, which made me look for the fire extinguisher!).  So it wasn’t electrical…

I drained 5 litres out of her.  There should have been 3 of oil…  It was *very* thin, so I wonder if she’d been burning oil latterly.  No black smoke that I can remember, but?  I did check the oil regularly, so it would be a late development.

I’m hoping 2 things: one, that the petrol got in there at the time the float stuck and p*ssed petrol all over the floor, and two that I haven’t damaged the engine internals.

Once the smell of petrol has diminished in the garage I’ll go and see if the fuel is getting through to the engine now (I clamped the petrol line to stop any leakage whilst it was erupting from the filler: I couldn’t remember for certain which way the petcocks turned for off!).  If not, then I’ll hope that the fuel got in there earlier and that no damage was done.

Should I be looking/checking elsewhere?  This has never happened to before, so I've never had to deal with the fall-out.

Thanks!

Paul

If the float's been stuck down, and you left the tap on, then yes, the fuel will continue to flow, and quite happily follow gravity down through the inlet manifold and into the sump via the cylinder. If you drained it, and refill with fresh oil, it shouldn't do any harm. People used to mix petrol with oil in the early days, for easier starting in winter. Not recommended, but they did...

Thanks for the re-assurance.  These things are mostly robust, and it hasn't been under stress, so I'm hopeful all will be well.

Taps are off with the lever horizontal, but the seals are readily damaged by modern fuel, and they will leak eventually.I kept mine to a minimum by dispensing with the right hand tap altogether, and blanked that outlet off with a threaded plug and washer, so I have only one to worry about, and no t-piece.

That's a thought for the future.  I had the taps out for a clean, and they are not the originals.  They have a reserve position, but it's not marked on the tap(!).  I *think* that the RHS is forward for off, down for on back for reserve, the LHS obviously vv.

I'm waiting for some crush washers (the sump plug was sealed with a red gasket-in-a-tube substance) - 45mm id is not a common size - so I left both taps 'on' yesterday afternoon and there's now no sign of fuel dripping through, so the rebuild of the carbs must have worked.

If it were me, I'd change the oil again after a couple of hundred miles, You won't have got all the contaminated oil out by dropping the sump oil, as much will be left in the timing chest. As oil's much cheaper than an engine issue, for me it would be good insurance to change it again.

Thanks.  This is good advice and I wouldn't have thought of this myself.

You're not alone; I read years ago of someone with a Suzuki 2-stroke T500 who wrecked his engine when his diaphragm fuel tap failed, filling the crankcases with fuel. First kick threw the fuel into the cylinder, where it formed a hydraulic lock, and as he jumped up and down on the kickstart to try and free it off, having no idea what had happened, he bent a con rod, and needed a rebuilt crankshaft

Nothing's new, though even at my age too many things are new to me!  I've heard various similar horror stories, which is why I thought I'd ask the group.

Thanks again!

Paul

Mine needs to be rebuilt because of this, but I rode it for a thousand km with the crankcase full of petrol.

In your case I think anything will happen and if something has worn out then you'll hear it.

Br,
Kris