Re: Onan generator does not start
I had a similar problem recently. I tried everything and like you the engine eventually seized. The problem was a leak in the exhaust elbow which was spraying water back into the manifold internally. The exhaust manifold was completely blocked. I had to have the engine rebuilt even after cleaning the manifold because of some surface rust in the first cylinder which is why it was seized.
2001 Amel SM2000
Ser No 326