Very fast idle with new Dellorto's fitted

[WarrenZ]

Finally got my triple Dellorto's and extractors bolted up to my 240. After some initial problems getting it started, 4 blocked pump jets and fouled plugs it finally fired up but immediately jumps to 4000 rpm idle.

The butterflies are fully closed and the idle mixture screws are fully in.

I cannot figure out where it is getting all the fuel and air from with the throttle basically closed. Has anyone else experienced this problem?

The carbs were disassembled and professionally cleaned and new gaskets, o-rings etc installed during re-assembly. Have I put something back incorrectly?

The carbs are DHLA 40G's

Warren

[e_racer1999]

have you checked your timing? also, you may have a vacuum leak somewhere.

[zKars]

Do the vacuum check for sure first.

I would disconnect each carb from the linkage and CONFIRM that all the butterflys are closed. I have had plenty of trouble with this in the past, though usually just one rogue carb being slightly open more than the others. Can't imagine other than something really wrong in the carbs, how you'de get 4K with the carbs closed.

Good luck.

Jim

[WarrenZ]

Problem solved

All is not what it seems when you are checking if the butterflies are fully closed using a mirror to look through the chokes and it feels like the linkage is fully home.

The centre carby was not quite closing off. I loosened the nuts on the shaft that works the butterflies and all OK. Amazing what a slight gap can do.

As you said z137, just one rogue carb.

Thanks for the tips

Warren