builder77 said:
The thing is I could just as easily open my passenger windshield, slid over into the passenger seat, give it a little throttle with my left foot, and spray some starter fluid toward the intake with my right arm out the windowshield while cranking it. $150 kit vs. $2 bottle starter fluid.
You DON"T want to do that! That it way too much ether. While commonly called an ether start kit, it is more correctly an ether ASSIST start kit. The engine does not actually start on the ether. The start kit only injects 4-6 CCs of ether over a six second interval, while you are cranking the engine. Each cylinder receives a tiny whiff of ether.
Since the ether has a very low auto ignition temperature, it fires well before the injector fires. As it is but a tiny amount of ether, the only effect is to slightly increase the cylinder compression but more importantly to raise the temperature of the air in the combustion chamber. Then when the injector fires, the fuel is injected into pre-warmed air, much in the same way a flame heater works.
If you were to spray a large amount of ether into the intake, too much ether could get into a cylinder with potentially disastrous results. The ether would ignite way too soon in the compression cycle and could either break something expensive, or start the engine running backwards. Yes, multifuel engines will run backwards, as has been noted in other posts, but it is not a good thing to do!
And yes, I have seen military mechanics spray ether directly into the mushroom inlet to start a balky engine, but it is not their truck and they don't have to pay for the repairs!