Flooding

[mint 61]

Got clutch issues worked out, took it for a test drive....aaaand broke down at the gas station. It ran like a scalded dog until it died when pulling into the gas station. It seems to have flooded itself. Let it drip out of the intake for a while, about 10 min, and it started back up. I'm guessing it's a fuel pressure problem? I took apart and cleaned the mechanical fuel pump, but didn't replace the diaghram a year or so ago. Is there any at to adjust the output pressure? Is an aftermarket inline fuel pressure regulator the best answer?

 

[RootesRacer]

If you are running the stock mechanical pump then you do not need a regulator.
The spring pressure in the pump sets the max pump pressure.

If the bowls are overflowing, look into float height or the floats having fuel in them or replace the needle and seat.

 

[mint 61]

Rebuilt carbs, new needles, I can't remember if I put new seats, everything seemed to be fine, I'll check the float height, no fuel in floats during rebuild. Is there anything else that could be causing this?

 

[RootesRacer]

dirty needle and seat is most probable.
The filter in the pump is a birdstrainer at best.
Equip a second filter after the pump after you are sure the fuel lines between
them are free of dirt.

If you can test fuel pressure it should be 1.5 to 1.75psi.
The stock needle and seat can take about 2.5psi before they cant hold back the pump pressure.

 

[chazza]

Good advice from RR!

When you replaced the mechanical pump, did you replace the two gaskets and insulating block, where the pump connects to the engine block?

The thickness of all three will affect pump pressure, if they are left off,

Cheers Charlie

 

[mint 61]

I think I got it straightened out, I pulled the needles, everything looked clean and fine, put it back together seems be alright now. Gremlins I guess.

 

[Tom H]

Not gremlins, but probably dirt.

 

[mint 61]

Maybe dirt... or Gremlin poo.

 

[mint 61]

The flooding is back! And my sunbeam is sitting in my brothers yard, and it won't start. This problem has been recurring before and after I rebuilt the carbs. It runs great when it's running. It usually starts back up after the excess fuel drains from the bolt on the bottom the manifold, about 15 min or so, but not this time. Any ideas?

 

[RootesRacer]

Did you check and possibly lower your float level?

Float level maybe high but acceptable when the engine is running but when it stops, the inevitable bleed past the needle can overflow a marginally set float height and into the intake.
A little dirt is all it takes to overflow the bowl when it sits.

 

[RootesRacer]

Oh and did you ever measure your supply pressure?

You may have an aberrant pump.

 

[mint 61]

Went back a couple hours later, started right up and ran great. It's the inconsistency that has me stumped. It will sit and idle just fine. I guess I'll pull the carbs apart tomorrow, and check float levels, dirt, etc.

 

[mint 61]

How do I measure fuel pump output pressure?

 

[chazza]

It's the inconsistency that has me stumped. I.

That is because when the engine is idling it can keep up with the fuel delivery; when it stops, the level must be rising as RR says.

To test the pressure you will need to tee-in a pressure gauge on the delivery side of the pump. Test-gauges should be available from any good auto store.

Did you check to see if the spacer-block and gaskets are on the pump mounting?

Cheers Charlie

 

[mint 61]

Just got it home, died on the way, had to get a tow. Ran like total crap the whole time. Something is really screwed up. I'm gonna have to go over everything. Adjusted the timing the other day, but ran great just afterwards, I bet it's got something to do with it too. Back to the drawing board.

Thanks for the reply Charlie, I'll check fuel pressure and spacers.

 

[RootesRacer]

Did you check and possibly lower your float level?

Float level maybe high but acceptable when the engine is running but when it stops, the inevitable bleed past the needle can overflow a marginally set float height and into the intake.
A little dirt is all it takes to overflow the bowl when it sits.

Dont forget about the float level.

 

[mint 61]

I removed the floats to check for dirt again, just barely bent the tab from the float to the needle, to lower float level on both carbs. Where exactly should the float level be set? The level of fuel in the bowls doesn't look like enough to overflow, but I can't be sure of anything at this point.