A friend of mine called this afternoon cussing the 28 efi he has for all it was worth. He said he liked about 20 minutes being finished with a big job and ran out of gas in his right tank so he did what I told him to do if he ever ran out of gas and it did not work. He turned the switch on for a couple of minutes without trying to start the engine this is suppose to prime the system and it still would not crank, so I told him his check valve was stuck on the end of the fuel pickup line in the tank. I said take the line out of the tank and pull the check valve off put the line back in the tank and turn the switch on but don't try to crank it until you think the system is primed. He did this and it cranked right up and when he pulled the check valve back out of his pocket he sucked through it and for some reason it had freed itself, who knows why I thought he would have to manually break it lose but didn't. I told him to switch the mower off and put the check valve back in the line if he could while holding it under the gas so there would not be any air in the line even though I don't think it would have mattered I didn't want to hear him cussing any more. I have not had it happen to me but I've heard of a few check valves sticking like this on the 28 efi's.