RB30, potential auto choke issue?

[dom14]

Yes, stove pipe thing shouldn't make any difference in VIC temperatures. But, dunno about sub zero alpine temperatures though, which can depend on your carby condition and tuning. Mine doesn't have the stove pipe or the shroud at all. Drives just ok in high altitude, but fairly gutless. I think the moist air doesn't help and even though the cold air does help for more boost in theory. The solution is to make the air/fuel mixture rich, which I'm not too sure the job of the auto choke.
It's not too hard to find out whether the auto choke is working ok, but an intermittent problem can be pretty tricky to locate.
Sticky throttle shafts can be intermittent issue, or may not show during your typical throttle test.

You can also try what I suggested above, which is adjusting the choke lean/rich setting.

I would first give the carby a good carby cleaner spray clean while revving high.
IF that doesn't help, pull the carby out and tighten the three bolts that holds the throttle body to the float.
Since the gaskets aren't available on their own, you might have to cut the gaskets using gasket paper or spend $78 and get a rebuild kit.
If you do rebuild it, take time and do it properly. Plenty of carby cleaner to clean the interior passages and plenty of high pressure air to clean the gunk.
Be careful with the plunger boot, as it can break easily. Don't loose any springs or balls inside the float, 'cos springs aren't included in the typical rebuild kit.

[Bigcol]

I think you will find it will either be the Needle and seat in the carby
or
a blockage in the fuel line

works fine
except when cold late night

check the connectors to the fuel pump at your tank

[dom14]

Just to be sure, check the fuel pressure, fuel filter(change it) and check and clean the gauze filter.
Intermittent fuel pressure problem due to a faulty fuel pump connection or fuel pump fault issue can be hard to diagnose.

[Bigcol]

Just to be sure, check the fuel pressure, fuel filter(change it) and check and clean the gauze filter.
Intermittent fuel pressure problem due to a faulty fuel pump connection or fuel pump fault issue can be hard to diagnose.

it IS hard to diagnose
long laborious headache
yes, check all filters, lines etc - maybe filter is partially blocked - with cold weather it is blocking the feed in
make sure there is no leaks from any of the lines - while under pressure
check all wiring & connectors - anything that looks dodgy - replace

last 2 ports of call
carby kit - or professionally serviced exchange
pull out tank and clean tank and filter in pump

however,
not revving is fuel starvation - which could be blocked filters
or
the Needle and seat is not opening - the spring maybe cactii - or the rubber tip may be on its way to being cactii

[dom14]

tank pump failure is rare in RB30 s. But, bad electrical connections can create havoc.
Checking fuel pressure can rule out fuel pump/blockage issue. Better to do it while revving the engine high and low, to make sure the pressure is enough for both idling & WOT.

[Throbbinhood]

Turned out to be a hole in one of the vac lines - or so I believe - replaced the line but haven't had any cold enough weather.

Silly me, I didn't mark the choke's original position before I adjusted it. Does anyone know what the factory or ideal setting is for these?

[Throbbinhood]

Any ideas?

[dom14]

Any ideas?

There are marks on the choke bimetal piece and the choke body. Normally two marks need to be aligned with each other to be optimum.
But, in some cases you might have to turn clockwise or anticlockwise to make it rich or leaner, depending on the seasons or the climate.

Ideally, when cold starting, the choke flaps should totally close the passage.
But, mine never did that, but the vehicle was starting fine without it. It was kinda slightly open even when freezing cold, allowing some air to pass through.
I'm yet to experiment with it to see whether it helps to adjust the choke to close the flaps completely during the winter.

[Throbbinhood]

Thanks Dom. Looks like the one in the picture is adjusted a bit off haha! I'll line it back up and see how we go! Still starts alright with it off, but coughs and splutters a bit more than I'd like.

[dom14]

Thanks Dom. Looks like the one in the picture is adjusted a bit off haha! I'll line it back up and see how we go! Still starts alright with it off, but coughs and splutters a bit more than I'd like.

Hi Chris,
No problemo. The choke flaps are slightly opened in mine(cold starting) when the choke alignment marks are lined up. Only way to close the choke flaps completely when cold was to turn the choke bimetal assembly anticlockwise. For some reason, I didn't feel right about it, so I left the factory setting of them lined up. What you see in the picture is when I was fiddling with it.
Let me know, if yours is the same, and don't be afraid to experiment with it. Bimetal spring is pretty strong. You can't break it unless you turn it 180 degrees or something.
Cheers
Dom