Difficult to start at my wits end

[RDfella]

5 pages on this now and I've read probably all replies, but in case I've missed one, can I ask - have you tried another carb yet? Was mentioned way back.

[RichardL]

A month ago, I was sitting in a bar/restaurant nursing my leg because my A10 wouldn't start. https://www.a7a10.net/forum/index.php?topic=2611.msg158893#msg158893

Not totally sure what the reason was at that time, but after I finally got her started and home, I changed plugs and wiped the slip ring for good measure. She has been starting easy ever since. I just now ran out to the garage and gave her a two-kick start for fun and just to be sure I wasn't BSing. I know this doesn't apply to your situation, 500, but you are going to be so happy and p'd-off at the same time when you discover a probably simple thing that's been causing you all the trouble.

Richard L. 

[KiwiGF]

It is a issue when threads get this long, I have just flicked through from the beginning and I actually don’t know what the current issue is eg hard to start (but then runs fine) or starts then stops.

I don’t think fuel taps would affect starting, so it does make a difference what the current issue is.

I also noticed the carb is a 1” monobloc, which (unlike a concentric) has the advantage of being able to observe the float in operation and consequently things like fuel supply can be eliminated as a cause easily.

[Superflash]

Ideally, you're looking for 300ml per minute from the taps.
Well that's the magic number that's recommended for feeding Amal concentric premiers anyway.

[RDfella]

Ideally, you're looking for 300ml per minute from the taps.
Well that's the magic number that's recommended for feeding Amal concentric premiers anyway.

Wow, that'd be some fuel consumption!

[orabanda]

Perhaps post a short video of the fuel flow out of the open hose?

[BSA500]

I can never get the pictures/videos small enough to upload god knows I've tried

[Triton Thrasher]

Ideally, you're looking for 300ml per minute from the taps.
Well that's the magic number that's recommended for feeding Amal concentric premiers anyway.

Wow, that'd be some fuel consumption!

More flow than you need is better than less flow than you need.

You want the flow to be enough (with a bit to spare) for that time you use full throttle and maximum revs to overtake something, with the petrol in the tank at a low level.

[RDfella]

You want the flow to be enough (with a bit to spare) for that time you use full throttle and maximum revs to overtake something,

Agreed. But here we're trying to resolve a starting issue.

[BSA500]

Right we have a runner. Firstly Andrew skills as a magneto builder are still safe nothing wrong with that. At first would not start checked flow and for interest the BAP tao will flow 500ml in one minute.. So changed carb reluctant  as the spare carb I had was smaller and the air screw thread was knackered  but needs must and she started second kick and runs/ticks over quite well. I moved over every thing from the duff carb except the jet block and the body so the fault lays in there some where
 Very annoying especially as I had put in the ultrasonic bath and blown it through with the compressed air at 100 psi

[RDfella]

Way back - halfway down page 2 - Chaterlea John suggested the carb wasn't supplying pilot jet mixture, and I suggested trying another carb. Now, after trying practically everything except a different rear wheel, what stood out as the pre-eminent problem has finally been addressed.
I understand how frustrating it is to have an issue one can't resolve (I currently have two - a small generator with no spark and a Ford Focus that won't run properly) but for me the worrying thing with this case is how many distractions from the obvious culprit were allowed to frustrate the eventual solution. Has the engine got a spark, at the right time? Easy to check. Has it got compression? If yes to both, it's fuel - either stale or not getting there.

[CheeserBeezer]

I am delighted for you! I have loads of second hand carbs and bits so, if you want anything, give me a ring or send me an email. We've probably all got lots of worn carb bodies but you can get oversize slides from Surrey Cycles. I've used one and they are great.

[BSA500]

Thanks I am going to have a good look at the jet block and see if I can clear what I assume is a blocked pilot circuit. I deffo cleared the pilot circuit in the carb body

[muskrat]

G'day 500 
Finally after 2,1/2 months of frustration we have liftoff
I'd throw that carb that hard it'd be on it's 2nd lap of the sun
The best thing I've done recently is put a new Premier Concentric on the old girl. Not cheap (3/4 of a weeks pay) but worth every cent.
Cheers

[BSA500]

Problem was these two issues over lapped the mag and the carb, one minute a breakdown with what looked like a blocked pilot then a mag misfire with internal short  The carb is inreally good nick not bowed resleeved good threads but with what seems to be a blocked pilot circuit I mean I have a knackered carb on and  she ticks over haha(a lot of that is Andrews rebuilt magneto I bet)