petrol

[Johnno]

Hiya all.I"m having trouble priming petrol from the tank of my "52 mm.The pump works perfectly on the bench and the fuel line is clear to tank.Is there a non return valve that can jam?Many thanks all.

[rayofleamington]

Hi Johnno
I'd guess the 52 petrol tank is similar to the 54 tank that I had problems with.
On the end of the fuel pick-up pipe (inside the tank) there was a metal strainer. On my tank this strainer had become completely blocked!
It is not easy to see but you can catch a glimpse of it through the hole where the fuel level sender fits.
After spending a day messing with pumps and the fuel line I eventually realised that the problem was the tank itself
My car had been sitting for 20 to 30 years an in that time the debris has solidified over the straner and I had to wreck the strainer to allow petrol to get past it.
I'd not heard of this problem before so it's certainly not common but it is worth to check it out. On mine I was quite lucky that all the tank screws came out easily so apart from having to empty the half full petrol tank it was quite easy.
I emptied the tank using the petrol pump and dipping the open end of the fuel line into the tank through the fuel level sender hole. It took about 5 minutes per gallon and I had enough 1 gallon petrol cans to cope, which is the only advantage of having such a small tank!

[Onne]

not that I'd want anything to blow up, but could you try with a compressor, and an air gun? Maybe it frees of. Might be wise to take the fuel cap off though.

Onne

[Johnno]

Many thanks to both of you.I will try out the air line first .If no luck ,looks like the harder option.Like your car Ray ,mine has been off the road for a similar length of time.So it looks the more likely option.Once again,thanks.

[Judge]

I don't want to be a party pooper, but if in the past the tank has been left empty of fuel for an extended period of time, condensation could have resulted in a considerable amount of rust forming. This will continually block the filter until it is effectively dealt with. I know, I've been there

[RobThomas]

On my sprite I had some probs when the nipple on the end of the fuel line, where it screws into the tank, wasn't sealing and so would suck in air at high rpm.
Tighten the nipple or put BLU-TAC on it? It sets solid after being exposed to fuel (or at least it always used to) Great as a temporary sealer.

[Johnno]

Many thanks to you all.I have taken in all comments and will look at all options.Again, thanks.

[rayofleamington]

Yes - I forgot that bit. On mine I connected my welding gas bottle to the fuel pipe to try to blow into the tank - somehow it withstood a few hundred PSI without letting any bubbles into the tank!
If your connection to the tank is leaking you will hear a 'hiss' from the connection.
One thing that makes it more complicated is that the fuel pipe connection also seals the fuel pick up pipe, so if you disconnect the fuel pipe the pickup pipe is not sealed at the outlet, which can cause confusion.

[Kevin]

When I tried this with a pal on a non minor a few years ago we put the compressor onto the line with the petrol cap off and after a few goes the tank sort of burped, it was then inserted into to filler but packed out with a piece of cloth to make a type of seal and blown again to make sure the line was clear but be careful and make sure somewone is at the other end of the pipe with some cloth to catch the outflow (hopefully)

[Johnno]

Hiya all,well I tried the compressed air in tank ,to no avail.Took off the connection on tank and blew the air line up pipe.No problem here,full flow at carb end.Looks like the tank pickup is blocked.I will investigate further!!!All the best,John.

[Judge]

Sounds possibly like the old rust problem