I am writing as a new member in order to perhaps offer help to anyone who may have had a similar experience with their onan generator. I purchases a Searay sedan bridge 52 in May in preparation for a trip from Florida up the east coast. I had the engines and Genset serviced before leaving. The onan generator started right up and about 4 hours later died while under way. I got a 36 code, non specific shutdown. It would not restart until it sat for awhile. The next day it started up again and died in a few hours. This continued all the way up the coast. In Charleston I had it looked at and it ran like a top. I scoured the internet for possible causes. A couple of weeks ago it died again while under way and this time I went below and opened the bleed screw and air was present in the line. After bleeding it started again and each time it died I found air in the fuel line between the lift pump and the injector pump and each time it restarted after bleeding. An attempt was made to search for a fuel line leak and none were found. It turns out that the lift pump, as it got hot and weaker, could not keep up with the injector pump, and a negative pressure caused bubbles to form, thus shutting the engine down. A new lift pump cured the problem and now it runs like a top again.