Friends and family said this would'nt work...LOL
Well, I got tired of messing with the carb every season on my craftsman. So I walked over to my Oldsmobile Van and poped a fuel injector out of the fuel rail along with the wires.
Drill and tap the intake of the lawn mower and installed the GM Injector. Now the carb works as a thottle body. I then wrote code for an Arduino micro controler to run the injector and monitor sensors(like an ECU on a car). Here is a picture of the workbench prior to the install.
I used a ULN2003 IC Chip to drive the injector, and a pot to change the pulse width. The mower started on the first try and after 3 code adjustments it would idle smoothly using 5ms injector pulses with 20ms between each pulse. I tied a pot to the govner to monitor throttle position. When the governor moves addind air, the Adruino micro controller responds by increasing the pulse width keeping the fuel mixture correct.
To start the mower I set the pulse width to 5ms with the pot on my control panel. Thats the amount needed for idle condition. When I want to mow or engage the mower deck I turn the pulse width up to 11 or 12ms and raise the throtle lever to full throtle this opens my throtle body(old carb) about 10%. From here the governor and the code below handle everything else. If the engine goes under load the governor kicks in and opens the throtle body turning the pot connected to the governor, so if the governor pot reads 980 I subtract that from 1000 and add it to the value of my fuel trim pot, now we have 1000-980+11 = 31ms injector pulse. Then the engine RPM's recover and the govner pulls back to 1000.
I really need to do a youtube video of this cutting the lawn.
Best of all ----> Next year my mower will start up and run
I will be putting togather a schematic soon..
The pump is a Mr. Gasket 7 psi. Before installing the injector I played with the pulse width by watching the spray patern on a piece of paper. My findings were that lots of small squirts are much better then longer ones, 2ms pulses are hardly visable and 100ms pulses are like pulling the trigger on a windex bottle.
Well, This project is working 100%. The control panel is mounted, wires are all cleaned up and encased. Today I mowed the lawn/weeds with my fuel injected mower. It has never ran better or had the power that it has now. The seat out of my old van welded on makes for a smooth ride. I also added (3) switches on the control panel, Arduino Power ON/OFF, Fuel Pump ON/OFF and Injector ON/Off