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Ted Edwards
 
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Default Building a Homemade Fuel-Injection System on a Briggs and Stratton 5 HP Engine

Ecnerwal wrote:

Let's see - you need an O2 sensor, you need a fuel pump, you need an
injector, and you need a little computer to control it all. You may also
need an array of other sensors, such as various temperature readings. So
you'll be adding a generator if the mower does not have one. If it were
me I'd add a better muffler along with the O2 sensor, since I just don't
think the standard lawnmower exhaust is even remotely quiet enough.


Gross overkill for the application. SInce you wish to operate at
essentially constant rpm and nearly constant power at fairly well known
temperature and pressure, the requirements are much less. Cars need to
run over a wide range of environmetal conditions and over a wide range
of speed and torque.

In the late 60's, I had a Cessna 205 which had an injected engine.
There was a fuel pump and a bypass valve to control the pressure at the
injectors and a throttle butterfly to control the air. IIRC, the
throttle affected both the bypass and the butterfly and the mixture
control affected the fuel pump or possibly was tied into the bypass.
The injectors were partially pinched of pieces of copper tube that
sprayed the fuel into the manifold just before the intake valves.
Performance was good as was fuel consumption so the simple system
obviously worked.

Ted