Carburetion with a diaphragm carburettor

Carburetion with a diaphragm carburettor

Normally, non-shifter kart engines use two types of carburettors: diaphragm and float-type. Although they have the same task (mixing air with fuel), the way they function is completely different. We will analyse the diaphragm carburettor, which has the advantage of allowing the carburetion to be adjusted directly on the track.

In itself, this is a simple task, provided you follow certain steps and carry out a few checks before proceeding with the actual carburetion.

PRELIMINARY CHECKS
For carburetion to be efficient, the entire kart needs to be “work properly”: the gear-sprocket ratio, which needs to be suited to the circuit, the spark plug, with an appropriate heat rating: this is the only way to fully exploit the characteristics of the engine’s delivery.
Whether the gasket between the carburettor and the reed valve pack is inserted with the hole for the vent on the correct side also needs checking, unless you use a dual-hole gasket that allows mounting on both sides.
The rubber connectors between the filter and the carburettor must be properly fastened using metal clips and a check needs to be performed to see whether wear and temperature changes have resulted in cracks and, consequently, the infiltration of air.
The mixture should respect the percentage specified by the engine manufacturer: different oil/petrol ratios modify carburetion and can cause engine seizure.
The air filter should be clean to ensure proper suction. It is advisable to clean the filter after each day at the track.

THE THEORY
On diaphragm carburettors, carburetion is adjusted using two screw pins: the one closest to the engine modifies the fuel mixture at low revs, while the one towards the air filter adjusts the high revs. The screws affect the fuel lines: tightening…(keep reading on the “HOW TO…” TKART Magazine channel)

IN PRACTICE (…)

CHECKING (…)

TIPS (…)

(keep reading on the “HOW TO…” TKART Magazine channel)