clicking sound after failed start

I have a Cessna 152 with the O-235-L2C. When I don't prime enough and have
a failed start, I frequently hear a "clicking" sound from under the cowling
after I stop cranking. I think it may be coming from the battery. Is this
the battery contactor opening/closing? It does not seem to be a problem;
just wondering what the sound is.

Thanks for any help.

Matt

Matt,
If the clicking sound you hear occurs while the prop is still turning, it
probably is the magneto impulse coupling or couplings...(some 152s have
impulse coupling on one mag, some have couplings on both mags. Either is
OK).

If the clicking happens when you cycle the LH part of the master switch, it
is the battery contactor. If the clicking happens when you rotate the
ignition switch to the "start" position, it is the starter contactor. Look
at the 152 POH Figure 7-7 for a pictorial of the electrical system to help
in the explanation.

John Severyn
KLVK

"Matt" wrote in message
...
I have a Cessna 152 with the O-235-L2C. When I don't prime enough and have
a failed start, I frequently hear a "clicking" sound from under the cowling
after I stop cranking. I think it may be coming from the battery. Is this
the battery contactor opening/closing? It does not seem to be a problem;
just wondering what the sound is.

Thanks for any help.

Matt

Correction....
If the clicking happens when you cycle the "RH" part of the master switch,
it
is the battery contactor.
John Severyn
KLVK

"J. Severyn" wrote in message
...
Matt,
If the clicking sound you hear occurs while the prop is still turning, it
probably is the magneto impulse coupling or couplings...(some 152s have
impulse coupling on one mag, some have couplings on both mags. Either is
OK).

If the clicking happens when you cycle the LH part of the master switch,
it is the battery contactor. If the clicking happens when you rotate the
ignition switch to the "start" position, it is the starter contactor.
Look at the 152 POH Figure 7-7 for a pictorial of the electrical system to
help in the explanation.

John Severyn
KLVK

"Matt" wrote in message
...
I have a Cessna 152 with the O-235-L2C. When I don't prime enough and
have a failed start, I frequently hear a "clicking" sound from under the
cowling after I stop cranking. I think it may be coming from the battery.
Is this the battery contactor opening/closing? It does not seem to be a
problem; just wondering what the sound is.

Thanks for any help.

Matt

That's normal. When you hit the starter you engaged the starter. The
starter will stay engaged until the prop reaches 300ish RPM. As you
turn the prop you are listening the starter turn.

-Robert

There's a ratchet in that starter drive, and as the drive is locked
engaged until the engine starts and the higher RPM disengages the
locks, there'll be a rattly clicking sound from the ratchet if the prop
is turned in its normal direction of rotation.

Dan