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smithvilletx's avatar
smithvilletx
Explorer
Apr 07, 2014

2005GENERAC 7.5 KW DIESEL GENERATOR

My Generac 7.5 diesel generator has worked great for nine years (abeit it only has 491 hrs. on it). The problem is that when I try to use the preheat button it blows the 14 amp fuse. If the temperature is not too cold it will start and run fine without using the preheat. It blows the fuse if you use both the remote preheat button or use the preheat button on the generator. I can't find any wiring problem or shorting problem, everthing seems ok.
Any ideas if the problem is within the three cylinder diesel engine or am I not catching a wiring problem?Thanks guys!

2 Replies

  • mikeh449 wrote:
    heat coil in air inlet are shorted


    Unless you know something I don't, there's no heat coil in operation in these generators. About 99.999% of them use a small, Kubota, 3 cylinder diesel which, uses basic "GLOW PLUGS". That little engine also has an "ECM" or, engine control module. The ECM uses signals from the coolant temp control sensor located in the underside of the thermostat housing. Based on input signals from that sensor, the decides if and, for how long, the glow plugs need to be heated, prior to actually CRANKING the engine over.

    Onan puts out a chart to tell you just how long the glow plugs will take to heat, based what the temp is of the coolant. The colder that coolant is, the longer it takes the glow plugs.

    Now, if the OP is getting a blown fuse during a preheat condition, not exactly sure where point him to try and find the source of his problem.
    Scott