Fuel leak. Please help.

[jonwat]

13 minutes ago, Escape said:

I've not had to reset float heights, so let someone else explain about that (eager to pick up a few pointers myself!).

Page 34 http://foxed.ca/rx7manual/manuals/carb_book.pdf, it's also detailed in the Esprit manual 

[Escape]

27 minutes ago, jonwat said:

Page 34 http://foxed.ca/rx7manual/manuals/carb_book.pdf, it's also detailed in the Esprit manual 

I had forgotten the carbs are detailed in my '88-'90 manual as well. I just had a look and that description seems easier than what I had previously read in the Excel manual. 👍

Sean, if you want/need a manual, that can be arranged. 😉 

[kwandokun]

1 hour ago, Escape said:

I had forgotten the carbs are detailed in my '88-'90 manual as well. I just had a look and that description seems easier than what I had previously read in the Excel manual. 👍

Sean, if you want/need a manual, that can be arranged. 😉 

Thanks mate I think I have the manual somewhere.

[kwandokun]

Ok so I left the pump on for a while and observed.

Fuel no longer leaks from the plenum, but then it started to leak on the other side!

It looks like it was dripping from under the exhaust manifold!?

This is really bad. 

Does it indicate float needles staying open and allowing fuel to overflow into the engine block?

[Sparky]

Two areas, both previously mentioned:  carb float needles failing to seal, or regulator failure.  Carb tops off, check the needles.  But my money is on the regulator.  This is how Esprit fires start.

[jonwat]

1 hour ago, kwandokun said:

It looks like it was dripping from under the exhaust manifold!?

Are you sure you don't mean the inlet manifold? 😀

[kwandokun]

12 hours ago, jonwat said:

Are you sure you don't mean the inlet manifold? 😀

Pretty sure it's the exhaust manifold, as its on the left side of the engine. 

Hmmm, maybe my left tank has shat itself...

13 hours ago, Sparky said:

Two areas, both previously mentioned:  carb float needles failing to seal, or regulator failure.  Carb tops off, check the needles.  But my money is on the regulator.  This is how Esprit fires start.

Will check both and come back.

[Escape]

I guess if a piston is near TDC with both inlet and outlet valves slightly open, it is possible for fuel from the intake to get to the exhaust and drip from a poorly sealing gasket... But you'd have to have way too much fuel going to the carb(s) to see it drip!

Hope you soon find the cause! At least you have it down to 2 likely suspects. Could even be both, failed regulator delivering too much pressure to the carbs and preventing the float valves from sealing. I'd start with checking the fuel pressure, if that is way too high the valves have little chance of stopping the flow. (and @Sparky suggested it so it must be true 😉 )

[jonwat]

5 hours ago, kwandokun said:

Hmmm, maybe my left tank has shat itself...

That's about the only fuel could drip under the left had side 

[Sparky]

A tank leak would be left of engine, so easy to distinguish from potential manifold leak.  Seriously, I've seen a failed regulator fountain fuel out of filler caps, so it wouldn't surprise me to see it leaking from a (potentially) compromised exhaust manifold.

2 minutes under the car and you'd know if it was tank.

[kwandokun]

1 hour ago, Sparky said:

A tank leak would be left of engine, so easy to distinguish from potential manifold leak.  Seriously, I've seen a failed regulator fountain fuel out of filler caps, so it wouldn't surprise me to see it leaking from a (potentially) compromised exhaust manifold.

2 minutes under the car and you'd know if it was tank.

I'll need to get back under there and take off the shield to get a better look. 

If it was the tank leaking it should be leaking even if the pump was off right? This would indicate it's the regulator letting way too much fuel through as I only see leaks after the pump has been on for a bit. 

Also I found a plastic T hose that was all corroded and not connected to above the left tank. Is that for carb balancing? Is it a crucial piece?

 

[jonwat]

30 minutes ago, kwandokun said:

Also I found a plastic T hose that was all corroded and not connected to above the left tank. Is that for carb balancing? Is it a crucial piece?

Fuel Breather Hose 

[kwandokun]

14 minutes ago, jonwat said:

Fuel Breather Hose 

Lol pretty sure mines been missing this whole time. No wonder it's always smelled like petrol. 

I don't necessarily mind the smell mind you, just don't like it when it ends up on the floor!

[Rambo]

Especially when you're having a crafty fag 🚬

[kwandokun]

On 19/10/2022 at 21:09, Sparky said:

A tank leak would be left of engine, so easy to distinguish from potential manifold leak.  Seriously, I've seen a failed regulator fountain fuel out of filler caps, so it wouldn't surprise me to see it leaking from a (potentially) compromised exhaust manifold.

2 minutes under the car and you'd know if it was tank.

Noob question, but have a gauge to check the pressure regulator. 

I should be checking the pressure reading from the regulator to the carbs right? Not from the pump to the regulator. 

[kwandokun]

Ok so pressure to both carbs is dead on 4psi. Means the regulator is fine. 

This leaves stuck floats. 

In other good news, I put in some fresh fuel and left it to see if any leaks from tanks. None. 

The leak I saw must be from the engine after I had the pump on for a while. Not great either but at least can be attributed to stuck carbs letting excess fuel in. 

 

 

 

 

[kwandokun]

Guys, fuel leak fixed!

Looks like it was just the front carb floats keeping the needle open.

Had the pump on for well over a minute with no leaks. Thanks for everyone's input what an amazing knowledge base we have here. 

Now onto the starter issue lol.

 

[Sparky]

One has to wonder how the feck they ended up bent like that.

[andydclements]

I suppose you could adjust just one of the two floats to get to the right fuel/float height, but I can't see it's a good way of doing it.

[kwandokun]

14 hours ago, andydclements said:

I suppose you could adjust just one of the two floats to get to the right fuel/float height, but I can't see it's a good way of doing it.

They were all slightly off so adjusted them all back to spec. No more overflowing.