16. Starting fluid

It is best to never use starting fluid. Moreover, it is virtually never necessary to use starting fluid in an Atomic 4, unless there is something else wrong. If an engine starts hard (requiring starting fluid), but runs fine once it starts, the problem is almost always caused by the choke not closing completely.

In both early and late model engines (especially late models), the spring-loaded popet valve in the choke valve is designed to allow just the right amount of air to be drawn in through the fully closed choke disk itself to provide a quick sure start.

As far as cylinder wall wash is concerned, I think the problem is overstated in the Atomic 4. Due to the updraft carburetor design, it is almost impossible to flood the Atomic 4 (even with gasoline). The whole issue of cylinder wall washing is more relevant to downdraft carburetors, where an overzealous use of starting fluid can result in some of the liquid draining down through the intake manifold and directly into the cylinders. In the case of updraft carburetors however, gasoline or starting fluid would have to be “sucked uphill” approximately 6 inches before entering the cylinders.

The good news here is that even if you end up with fuel or starting fluid puddling in the intake throat of the carburetor, the liquid will vaporize while it is being drawn up through the carburetor and intake manifold, even with the use of full choke. - Updated: November 4, 2003