mice in my onan :) yes I had stowaways

I was working on my generator and got it fired up fuel pump ground wasn't making contact . and was getting some serious smoke . Come to find out there was huge mouse nest right on top generator inside metel shroud. I could just get shroud off enough to vacum out a big mouse nest. I mean acorns insulation and other fine stuff. Now my question how to keep mice out of my onan 4000 J they love it. fresh cab air freshener. screen ??? any ideas be great . taking shroud off is a big pain. also another question on gas line . Mine has hose going from pump to supply line just behind generator box then small metal line going all the way back to gas tank. but metal lines just laying on top of stuff loose resting on big exhaust pipe shields and floppying around up in there.
it looks like it goes back to rubber hose close to the big gas tank .
do I zip tie it up to stuff with plastic protectors :h??? any ideas be great . Thanks

Itasca55

P.s. on mouse nest it was still burning as it hit the vacuum it wasn't a pretty smell vacuum will never be the same :) no mice were harmed it was a vacant nest LOL.