i still have a fuel problem

hi again
i still haven't sorted the fuel problem out on my auto 89 clipper so far i've change the filter, pump and i have also checked the tank for rust using magnet's and yes i did get a bit of rust out but still there is none in the filter,  i've also tried to see if there was a vacuum problem so when it  stalled i removed the filler cap but there was no rush of air.  i'm now left with 2 parts i think i could change one being the carb and the other is the fuel reservoir or evaporator not to sure on the name of it.  this may sound a bit dumb but what does the fuel reservior do? and is there any way of testing it. the car itself start first time but after a small space of time or when i approach a junction the rev's go below 400 and it cuts out. this car has also been into my local garage a few times and they can't find the problem can anyone help?

Hi ya, i take it a carb`ed engine you have with a pierburg strapped to the top of the inlet manifold.

Just curious about your fuel problem, what problems have you got? No fuel at all from the pump? If you crank the engine over a couple of times do you get a large jet of fuel? if your going to do this then dont aim the pipe in your face, just used a milk bottle or somthing and dont smoke near it..lol

The reservoir does to things, it keeps the mechanical pump at a nice pressure so wont blow the internal diaphram by circulating the fuel back into the tank. If the output of the pump gets blocked the mechanical arm of the pump will "pop" against the intermediate shaft.

The pressure inside the reservoir also feeds the carb. which has a needle valve for the float chamber. When the chamber is full, the needle valve will shut, the fuel is then diverted back to the tank. Keeping the pressue constant and the pump happy.

If you connected the pump straight to the carb, then the pump would have a less of a life and a knocking would be heard from the intermediate shaft. Thats why they put one reservoir on them engines.

If your not gettin much fuel at the pump end, try blowwing down the pipes, see if you hear bubbling in the tank. If its well hard to blow, then you might have a blockage.

Another thing from way back i remember was a fuel problem feed, I was struggling to find why the car was`nt drawing fuel. Found out it was a small crack in the metal pipe from the tank. It was in the up hill direction into the engine bay so no obvious leak of fuel. The pump was drawing air and a spluttering of fuel. Replaced the whole fuel line in the end. Felt ok when i gave it blow through tho.

Hope this advice helps
Regards