P1800s starting issue

[old fart]

The float chambers are vented to the atmosphere, as is the fuel tank, so there is plenty of air about. My cars all have new fuel lines front to back, and the only one that starts fairly quickly after not being used is my 122s, which is always parked facing downhill. Don't know if this is coincidence or not.

[paul staines]

Originally Posted by Burdekin

Just one other thing Paul, does the choke work on both carbs and does it pull down the jet tubes all the way?

Choke working fine. Regards Paul

[paul staines]

Originally Posted by Laird Scooby

Just saying ^^^^^

Yes. That simplifies things. Air leak from tank to carburetors.
Will check. Cheers

[Ron Kwas]

Forum;

Fuel system comments and observations:

(Early!) SU Float bowl are indeed vented to atmosphere, so when parked long-term (a lot longer than overnight...more like two weeks!), the bowls do loose some level due to evaporation, but with a well adjusted and functioning Choke, I don't expect this to affect Starting until after twice that long again (and incidentally, the gum left behind can certainly be a contributing factor in the Bowlvalve sticking and Fuelbowl(s) overflowing).

Fuel Pumps already do have (2) unidirectional valves...these valves, internal to the FuPu work to allow only unidirectional fuel movement, but these sometimes seal less than perfectly, so an additional non-return valve is not really required (unless you want to "help out" a less than perfectly functioning FuPu)...less than perfectly sealing internal valves, wouldn't become apparent immediately, but over time (and this would be highly variable, including possibly intermittent, based on the wear of these valves, and how, and how much they are bypassing...this can make for frustrating troubleshooting of fuel supply issues!), would allow drainback of what is in the line going to carbs, powered by the weight of fuel in the column (but no more!...suggestion of bowls being emptied by drainback is highly optimistic and fantastic IMO...I just can't see how this can take place, since fuel drops into bowls, from the Bowlvalves, and no uninterrupted fluid column exists with which to form a bowl-emptying siphon!).

I like to add a final Fuel Filter (see-through or translucent) to just before the Bowls...in addition to giving the obvious last line of particulate exclusion defense, I can also monitor how long it takes during cranking before I see replenishment squirts arriving...if it takes longer than a second or two, I know those valves are bypassing, allowing drainback...

While troubleshooting a no-start due to no fuel condition on a looooong inactive Triumph (sorry!), I saw an instance of a completely empty fuel line (even on the intake side of the FuPu!)...so the FuPu had lost its prime, and was pulling I suspect, against air in the line, so we just couldn't get any fuel movement started...blowing into the fuel-filler of the tank during cranking attempts, to make a little pressure to encourage initial fuel flow to the FuPu, and fill the supply line with fuel instead of air solved that...

Cheers

[142 Guy]

Originally Posted by Ron Kwas

Forum;

blowing into the fuel-filler of the tank during cranking attempts, to make a little pressure to encourage initial fuel flow to the FuPu, and fill the supply line with fuel instead of air solved that...

Cheers

That must have been interesting for any bystanders observing that particular field repair. Probably generated some crazy person alerts.

[Ron Kwas]

142G;

The blow-into-the-tank-action took place at friend's garage on his Triumph (I could never own one of those!) ...I offered to help sort a fuel feed issue, as it had sidedraft carbs (ZSs, not even SUs!) so there where no bystanders (or even witnesses!) to call in suspicious activity...besides: What happens in the garage, stays in the garage!

Cheers

[142 Guy]

Originally Posted by Ron Kwas

142G;

no bystanders (or even witnesses!) to call in suspicious activity...besides: What happens in the garage, stays in the garage!

Cheers

As long as you remembered to wipe off the tell tale petroleum smudge around your lips before you went into the house.

[Ron Kwas]

...ain't no "tell tale petroleum smudge around the lips" on this mechanic! I practice Safe Tank!