25 replies to this topic

[nicklouse]

Can we have a photo of the carb and set up?

[Ethel]

I'm guessing it's a HS from the description & swing needle.

 

Think of the jet & float chamber as like a U tube barometer. The float has atmospheric pressure above it, courtesy of a vent in the lid, sometimes incorporated in an overflow pipe. The pressure over the jet gets reduced by air flowing over it and fuel gets sucked through. As the float chamber is emptied, via the jet, the fuel level drops. The float drops too allowing the float valve to open until the fuel level is restored.

 

The gravity fuel feed actually makes things simple to diagnose as you'll have a permanent & constant pressure. The float valve ought to handle a 3m head of fuel.

[timmy850]

If you remove the top of the carb including the damper, dashpot and needle the fuel level should stay at the same point in the jet even if the pump/head pressure is there. If it’s leaking up and out the jet hole it is definitely a problem

[[email protected]]

Hi folks. 

 

I have officially been given The title Of THE VILLAGE IDIOT......

 

I am so ashamed.

 

I went back to the beginning. Looked at all the advice. And my fuel hose was connected to the overflow from the bowl...not the inlet. 

 

No idea how that happened...but I take full responsibility. 

 

Thanks for all your help. I did read all the docs you guys linked to and I am now the local expert on SU carbs....but no one is going to call on the village idiot are they?

 

I do appreciate everyone's time and effort. Thanks for your support and I am sure I will be back when I can't locate the dipstick.     

 

I got the vehicle started for the first time in months. But due to unleaded fuel in the crankcase I need to get some new oil.

 

Approx 4.5 litres of SAE40? 

 

Thanks again to all, it was a great help. 

 

Last question before I go and bury myself in shame for such a basic error. What model is my carb? Seems I have a later model than what was shipped with the engine? 

 

cheers guys

[cal844]

Hi folks.

I have officially been given The title Of THE VILLAGE IDIOT......

I am so ashamed.

I went back to the beginning. Looked at all the advice. And my fuel hose was connected to the overflow from the bowl...not the inlet.

No idea how that happened...but I take full responsibility.

Thanks for all your help. I did read all the docs you guys linked to and I am now the local expert on SU carbs....but no one is going to call on the village idiot are they?

I do appreciate everyone's time and effort. Thanks for your support and I am sure I will be back when I can't locate the dipstick.

I got the vehicle started for the first time in months. But due to unleaded fuel in the crankcase I need to get some new oil.

Approx 4.5 litres of SAE40?

Thanks again to all, it was a great help.

Last question before I go and bury myself in shame for such a basic error. What model is my carb? Seems I have a later model than what was shipped with the engine?

cheers guys

4.5 litres of 20w50 mineral engine oil(assuming manual transmission).

Id advise changing the oil filter too so you'll need closer to 5 litres of oil

[Stevie W]

Hi folks. 

 

I have officially been given The title Of THE VILLAGE IDIOT......

 

I am so ashamed.

 

I went back to the beginning. Looked at all the advice. And my fuel hose was connected to the overflow from the bowl...not the inlet. 

 

No idea how that happened...but I take full responsibility. 

 

Thanks for all your help. I did read all the docs you guys linked to and I am now the local expert on SU carbs....but no one is going to call on the village idiot are they?

 

I do appreciate everyone's time and effort. Thanks for your support and I am sure I will be back when I can't locate the dipstick.     

 

I got the vehicle started for the first time in months. But due to unleaded fuel in the crankcase I need to get some new oil.

 

Approx 4.5 litres of SAE40? 

 

Thanks again to all, it was a great help. 

 

Last question before I go and bury myself in shame for such a basic error. What model is my carb? Seems I have a later model than what was shipped with the engine? 

 

cheers guys

Don't be ashamed! With this forums help and your own resolve, you've sussed the problem out, well done 

 

Cheers, Steve.

[Shooter63]

Hi folks. 
 
I have officially been given The title Of THE VILLAGE IDIOT......
 
I am so ashamed.
 
I went back to the beginning. Looked at all the advice. And my fuel hose was connected to the overflow from the bowl...not the inlet. 
 
No idea how that happened...but I take full responsibility. 
 
Thanks for all your help. I did read all the docs you guys linked to and I am now the local expert on SU carbs....but no one is going to call on the village idiot are they?
 
I do appreciate everyone's time and effort. Thanks for your support and I am sure I will be back when I can't locate the dipstick.     
 
I got the vehicle started for the first time in months. But due to unleaded fuel in the crankcase I need to get some new oil.
 
Approx 4.5 litres of SAE40? 
 
Thanks again to all, it was a great help. 
 
Last question before I go and bury myself in shame for such a basic error. What model is my carb? Seems I have a later model than what was shipped with the engine? 
 
cheers guys

SAE40 will be fine as you live in a part of the world that doesn't dip below 15c ( you lucky git )

Shooter

[Clip]

Hi folks. 

 

I have officially been given The title Of THE VILLAGE IDIOT......

 

I am so ashamed.

 

I went back to the beginning. Looked at all the advice. And my fuel hose was connected to the overflow from the bowl...not the inlet. 

 

No idea how that happened...but I take full responsibility. 

 

cheers guys

Don’t feel ashamed, I’m sure it’s happened to plenty of people. You did well to spot it, even folks completely familiar with SUs can make that mistake, just like I did only a few years ago rushing around and not concentrating on what I was doing, and I’ve been working with SUs for 30 years, so I absolutely don’t have any excuses. 

[Aly-g]

at least you had the decency to own up to your mistakes and let us know the problem has been solved, well done.

 

Allan

[Verderad]

If it helps, I'm about to put my carb back on the car.  I'm going to read the SU manual and check all the photos I took when removing as I can't remember which one was the inlet.  

[Chris1275gt]

If it helps, I'm about to put my carb back on the car. I'm going to read the SU manual and check all the photos I took when removing as I can't remember which one was the inlet.

Very simple check take the cover off the float chamber raise the float to seal the inlet and blow down one of the pipes one will blow the other won’t.

Edited by Chris1275gt, 25 April 2023 - 04:12 PM.