2018 Winnebago Vista 31BE, V10, Onan Marquis Gold 5500 with 340 hours on it. the coach sat from memorial day to labor day because of a hip. went out this week to run the gen before the fall trip and it cranks strong but will not catch. coach fuel gauge is at half, i know about the quarter tank cutoff. held the switch down to prime for 20 seconds like the manual says, twice, nothing. it ran fine in may. what am i missing before i pay somebody to drive out here.
mobile tech, i get this call about once a week every september. three things, in order.
one, the gas in the generator line is stale and the carb bowl is dry and varnished. ethanol fuel in a hot bay for 90 days will do that every time. two, the fuel pump on the generator itself, not the chassis pump, is tired. they start getting weak around 300 to 400 hours. three, spark or the low oil cutout.
quick test. pull the air filter cover, give it a shot of starting fluid into the intake while somebody holds the start switch. if it fires and dies, you have spark and it is a fuel problem. if it does not even pop, check the oil level on the dipstick before anything else. the Marquis will crank all day on low oil and never fire because the low oil pressure switch thinks it is saving the engine. that is the one people miss and it costs them a service call.
pat has it. i will add one. the generator pickup in the chassis tank is shorter than the engine pickup on purpose, so you cannot strand the coach by running the gen. on a lot of coaches that quarter tank cutoff is more like a third when the coach is nose down or leaning. your half a tank on a sloped driveway might be air at the gen pickup. get it level and try again before you buy a single part.
full timers, 2016 Bounder 33C with the same generator. ours did this exact thing in april after a winter in a storage lot. it was the carb. the little float bowl shutoff solenoid on the bottom of the carb was stuck, Cummins part, about 80 dollars, my husband did it in a Walmart parking lot with a headlamp. the part number is printed on the solenoid body. while you are in there, there is a small inline fuel filter on the gen that nobody ever changes. ours had never been touched in 9 years and it was brown.
leveled it first like ron said, no change. starting fluid: fired and died. so fuel. pulled the cover and the bowl was bone dry. sprayed carb cleaner through the bowl vent, put a new inline filter on from the Cummins dealer here in Mason City, 11 dollars, primed it 30 seconds and it caught on the second try. ran it 45 minutes with the front air on to put a load on it like the manual wants. smooth. thanks all. the solenoid i will keep in mind if it acts up again.
follow up for whoever finds this next september. it did it again after ten days of sitting, so i did the solenoid too. 78 dollars, half an hour, and now it lights on the first crank cold. the lesson for me is to run the thing an hour a month under load whether the coach is going anywhere or not, which is what the generator manual says and what the tech articles at fmca.com say if you are a member there. i just never did it.
