Chainsaws will probably be utilizing these in the near future, so I thought I'd post this here. 
These injectors are really expensive, so I actually took apart a dead one just to see what was inside, just out of curiosity.
They are a warranty item covered under epa guidelines for a two year period. This is a good selling point if your customer is squeemish about complex and expensive fuel injection repairs. This one was worn out and was not metering, (sealing) the fuel correctly. The stainless part on the bottom right in the picture below that has a hole in it is what the blue rubber seats against. The tip looks like it chewed up something that roughed it up.
Also you can see the matching deformation of the rubber in the top picture, which probably resulted from fuel quality, debris, high mileage, or just too many jumps to light speed.....lol
Even after a recalibration with the MDG-1 tester, the saw still couldn't compensate for the extra fuel.
It was ending up way to rich to maintain an idle because of the excess fuel loading up in the combustion chamber.
The square thing houses the bypass check valve, which looks to be electrofuse welded to the injector housing. There is a wire imbedded along a seal seam at it's base. It took a bit of head scratching to figure just exactly what the one wire was for.....
I used to sell an industrial acid waste pipe called "fuseal" at a pumbing wholesaler that utilized a similar seal method. Basically electrical current gets fed into each end of the wire, then gets hot and melts the two pieces of plastic housing together. This is after after a chinese worker puts the rubber check valve and it's return spring in, then covers it, and zaps it permanently in place.
The rubber check valve bypasses any pressure above 2.5 psi on the inlet line. If it's lower than that, there is something internally wrong with the injector.
The blue rubber is what is lifted by the solenoid in super fast cycles that let the pressurized fuel spray into the crankcase. The solenoid cyclic speed is regulated by the computer at up to 20 times per second at top speed, which is more like a vibration I'm sure.
As you can see, the rubber seal on this one is worn to the point that it is toast.
Most times they leak when you pump the primer, causing gas to pump right into the crankcase causing a no start condition.
These injectors are really expensive, so I actually took apart a dead one just to see what was inside, just out of curiosity.
They are a warranty item covered under epa guidelines for a two year period. This is a good selling point if your customer is squeemish about complex and expensive fuel injection repairs. This one was worn out and was not metering, (sealing) the fuel correctly. The stainless part on the bottom right in the picture below that has a hole in it is what the blue rubber seats against. The tip looks like it chewed up something that roughed it up.
Also you can see the matching deformation of the rubber in the top picture, which probably resulted from fuel quality, debris, high mileage, or just too many jumps to light speed.....lol
Even after a recalibration with the MDG-1 tester, the saw still couldn't compensate for the extra fuel.
It was ending up way to rich to maintain an idle because of the excess fuel loading up in the combustion chamber.
The square thing houses the bypass check valve, which looks to be electrofuse welded to the injector housing. There is a wire imbedded along a seal seam at it's base. It took a bit of head scratching to figure just exactly what the one wire was for.....
I used to sell an industrial acid waste pipe called "fuseal" at a pumbing wholesaler that utilized a similar seal method. Basically electrical current gets fed into each end of the wire, then gets hot and melts the two pieces of plastic housing together. This is after after a chinese worker puts the rubber check valve and it's return spring in, then covers it, and zaps it permanently in place.
The rubber check valve bypasses any pressure above 2.5 psi on the inlet line. If it's lower than that, there is something internally wrong with the injector.
The blue rubber is what is lifted by the solenoid in super fast cycles that let the pressurized fuel spray into the crankcase. The solenoid cyclic speed is regulated by the computer at up to 20 times per second at top speed, which is more like a vibration I'm sure.
As you can see, the rubber seal on this one is worn to the point that it is toast.
Most times they leak when you pump the primer, causing gas to pump right into the crankcase causing a no start condition.
