Hi, this is my first time setting up triple SUs after an engine rebuild. I followed instructions in the service manual and here.
Anyway, I did get the engine running a few weeks back, fired up almost first time, before I touched anything. But I can’t start the engine now (cold not helping likely). i noticed that when I do stop cranking i find pools of petrol have formed behind the bridge, is this normal?
Any advice?
It was normal on my Spitfire racer when the engine didn’t start or, the fuel level in the bowls was too high allowing gas to bubble up at the jet.
Flost level wrong. Sinking float. Bad seal at float valve.
Do not use choke when starting if you have fuel pooling.
I had a fuel pump switch on the Spitfire and always turned off the pump until the engine fired, then would flick it on.
HTH
Cheers Bill. I’ll try without choke.
All the float and seal hardware is new but I’ll also check it over.
Check for sticking fuel jets and make sure the floats is not sticking. Before storing the car away for Winter use STA-BIL. It will protect against fuel becoming varnish or what I use is a mixture of transmission fuel and gas. A quart of transmission oil to a five gallon of regular gas. It protects the fuel tank, fuel pump, fuel lines float bowls carb jets etc. It may smoke a bit on start-up or until the fuel burns off. It’s a cheap and easy easy way of protecting your investment. Cheers! 
If you replaced the floats double check you have the float height set correctly.
YW,
while you are in there check to see that the pistons are moving up and down freely with the dampers unscrewed.
Also, I would crank with the throttle wide open and clutch in to pick up a little speed
Good luck.
Better yet, instead of transmission oil use Marvel Mystery Oil. Same ratio. It’s also good to add to the fuel on fill up, acts as a top cylinder lubricant. Inside the motor it coats parts, a good insurance against micro rust. Available everywhere and really good stuff!! Been using Marvel Mystery Oil in all my vehicles for over 50 years!!!
I’ll agree with the use of Marvel Mystery Oil if you are going to have your car stored for an extended period; however my choice for short term or Winter storage will always be regular transmission oil and is less expensive. I’ve used Marvel Mystery oil in the past and I’ve not noticed any difference with both. I grew up with guys who used regular transmission oil in their manual transmissions instead of thick heavy duty tranny oil, primarily because of heat range during races and absence of the moisture content during cold temperature changes and lengthy storages…
do you mean ATF? or 20 other lubes found in manual trans.
Hi Bill, It’s a quart of ATF transmission oil added to a five gallon can of gas for the fuel tank, and ATF tranny oil for the transmission only, with NO petrol added. This is what they used…
Red ATF? Or one of the other kinds?
I use the red trans fluid…
So I have checked the floats and needles. They are fine, 11mm clearance on the floats and the needles don’t leak. Pools still form but only if the throttle is open. Starts about half way open and gets quite wet fully open. Does not do it if closed or just on choke.
The only thing i can think of now is that the new SU pump is over powered so I’m waiting for a regulator.
Other thoughts?
To test that theory, remove the bells and pistons, turn on the ignition and see if fuel flows from the jets
To check my carb jets I’ll take the bowl cover off but leave the fuel line attached. I’ll turn the cover upside down with the float closing the fuel jet with the ignition in the on position. This allowed me to see weather the pump has too much pressure or a leaky jets. Is it possible for you to do this procedure to know definitively your suspicions are correct…
Agree
Will,
check jet level
The fuel should not come out of the jets if you blow on them, the fuel will go down briefly and pop back up when stopping blowing. It may bounce a bit but should just be low enough to not let any fuel come out the top.
Garth,
If the fuel level is high in the float chamber, it will be high or even overflowing in the venturi.
If the pump is too high a pressure and over -powering the inlet needle… see above.
Take the top off the carbs, turn the key on and see if you have a steady leak. If not, pull of the float chamber covers and measure the fuel level in each. Adjust as needed. I went with 1" from the top edge of float chamber.
I have set my floats 'zactly at 7/16" and gotten 3 different fuel levels in each carb. As Nick S. said each SU is its own unique creation.
One can understand why in an emission control environment, why Jaguar might look at the.more precisely made Strombergs as a device with some degree of repeatability. Until that vacuum enrichment contraption stopped working !
Thanks all, I put a clamp on the fuel line to restrict flow and it started right up no flooding. Obviously stopped when fuel in the bowls ran out. I eased off the clamp a little, pump clicked, filled the bowls and hey presto she started and ran with no flooding. Regulator arrives tomorrow will fit that for a longer term solution.
Thanks for all the advice, i would never have thought about fuel pressure otherwise.
Next problem, I don’t like noise the the rebuilt engine makes… new thread to come…