Fuel in air filter box and inlet manifold

[andyt]

Hello, this is my first time on the forum, hoping someone can help. While driving a couple of days ago the engine cut out, I re-started but the engine was very lumpy possibly only running on four cylinders before it cut out again.
After checking everything was where it should be and tight I noticed there was fuel on the road underneath. After removing the air filter cover there was fuel in the box which looked like it came through the top hose connection on the box. Anyway having been towed home (first time, hopefully last) took the carbs off and there was about a quarter of an inch of fuel in the inlet manifold.
I stripped the carbs and could find nothing obvious. Was hoping someone may have an idea before I put them back on. Could it be an ignition problem? Any help would be greatly appreciated.

[StagnJag]

Hi Andy,

Welcome to the forum. You have come to the right place for help!

That sounds odd. Are you sure all of the pipework around the carbs is plumbed in correctly? When a carb overflows excess fuel should go down a pipe in front of the engine and exits just above the front anti roll bar.
There are people on here with much more experience with carbs than I have, but a photo or two may help.

Kind Regards

Dave

[Stagsongas]

Good thought Dave.

It may be that the overflow pipe has been incorrectly connected to one of the breather or vacumn points, allowing any overflowing fuel to flood the carb (s).

In any event, that would be a secondary effect, fuel being dumped in the wrong location. Why is it being dumped or overflowing will be the core question, and is that most likely due to worn or stuck float valves?

I'd encourage Andy to search on 'float valves' which should open up a wealth of info. Good Luck!

Regards

Steve

[andyt]

Thanks Dave and Steve, I'll check the pipes although the pipe the fuel came through was the connection on the top of the casting between the air filter and carb to the filter box which does seem odd. I'll also have a search on float valves.

Regards
Andy

[martin]

Hi Andy, it's the needle valves, as Dave says, flooding leads to petrol running out of the overflow - unless there's too much of it, and it backs up into the air filter. Replace both needle valves, with new ali washers, check and set the float heights, new O rings in the bottom of the float chambers, and two new gaskets, Bob's your Aunties husband. Martin.
PS, a small pool of petrol in the manifold is normal.

[andyt]

Thanks Martin I will order the parts tomorrow and hopefully be back on the road by the weekend.

Thanks again
Andy