[Richard]

Keep in mind while chasing this smell, that the generator compartment is pressurized by the generator blower fan. The discharge is directly under the coach of the cooling fan. So, any leak inside the compartment is going to exhaust directly under the coach.

Inside the gen compartment look carefully at the entire exhaust system, including the turbo, for any signs of soot or exhaust leakage. I know I fought a leak right at the turbo because a slip fit with clamp fitting had been used to attach the exhaust pipe to the turbo. I eventually welded the fitting to stop the leak.

As discussed before the exhaust pipe should be sealed in some way at the sliding junction. Mine does NOT have a bell or flare opening for the exhaust packing. I simply wrapped some fiberglass exhaust wrap around the inner pipe, used a couple of zip ties, and pulled the gennie back into the compartment. The wrap slid on the inner pipe to position it. I pulled the generator back out, slide the wrap 1/4 inch closer to the outer pipe, and secured it with a couple of radiator clamps.

And the exhaust system under the coach must be checked for integrity. Only way to do this, is get under there with the generator running. Hopefully, no one would consider that without proper cribbing. Pay close attention to the area where the gen exhaust and the Aquahot exhaust merge into the vertical exhaust section. That is a hand made piece and subject to corrosion.