Lotus Elan

do I have a fuel pump problem?

PostPost by: milton » Mon Nov 22, 2021 3:40 pm

fuel pump.jpg and
A new glass bowl fuel pump was fitted during a recent rebuild. The engine starts and runs with no problems although it hasn't been put under any load as it hasn't been on the road. I noticed bubbles entering the bowl when turning the engine over with no plugs fitted. The bubbling appears from the inlet side of the pump and continues for at least 20 seconds after the engine has been turning over. I'd like to think it might be petrol vapour but I suspect it is air. I've checked all connections between the pump and the tank for tightness. I had to split the pump before installing to rotate the top half so the inlet and outlet were in the correct positions but I think it was connected up correctly and tightly. There is no sign of petrol leaking from the pump. The bowl is not full after turning the engine over. Is there air entering the system? I'd welcome any comments or suggestions before stripping the pump down.
Thanks
Milton
milton
First Gear
First Gear
 
Posts: 24
Joined: 17 Aug 2016
Location: Northumberland, England

PostPost by: elanner » Tue Nov 23, 2021 2:16 am

The fuel bowl is unlikely to ever be completely full (i.e. without an air pocket at the top). I guess there are always some air bubbles frothing around. As the engine runs I wouldn't worry about it for now.

Where did you get a new pump? I didn't know that they were still available.

Nick
User avatar
elanner
Fourth Gear
Fourth Gear
 
Posts: 565
Joined: 14 Sep 2010
Location: Boston, MA, USA

PostPost by: milton » Tue Nov 23, 2021 12:05 pm

milton
First Gear
First Gear
 
Posts: 24
Joined: 17 Aug 2016
Location: Northumberland, England

PostPost by: 512BB » Tue Nov 23, 2021 2:01 pm

I fitted a new old stock AC fuel pump to one of my cars a couple of years ago Milton, and had to rotate the top half. Some time later I noticed and issue with the pump but I cannot for the life of me remember what it was! I have a feeling it was leaking petrol. Anyway, I tightened up all the screws that I could access, so that was all of them, bar one. They all needed tightening by about 1/4 of a turn. I don't think that they had come loose, but that the diaphram had compressed. No problems after that, what ever it was ! Give it a try.

'The fuel bowl is unlikely to ever be completely full (i.e. without an air pocket at the top)'

That is not the case on my cars Nick, the pumps run full right up. So much so that it is difficult to see if there is any fuel in them.

Leslie
512BB
Fourth Gear
Fourth Gear
 
Posts: 916
Joined: 24 Jan 2008
Location: Cambridgeshire, UK

PostPost by: elanner » Tue Nov 23, 2021 2:30 pm

512BB wrote:'The fuel bowl is unlikely to ever be completely full (i.e. without an air pocket at the top)'

That is not the case on my cars Nick, the pumps run full right up. So much so that it is difficult to see if there is any fuel in them.


That's interesting. I never saw mine completely full. I wonder why. (Currently I'm running a pump from R.D. Enterprises which doesn't have a bowl.)

Nick
User avatar
elanner
Fourth Gear
Fourth Gear
 
Posts: 565
Joined: 14 Sep 2010
Location: Boston, MA, USA

Total Online:

Users browsing this forum: geni and 12 guests