[Techmitch]

I saw those; earlier today I contacted the Lord Corporation https://www.lord.com/products-and-solutions/vibration-and-motion-control/industrial/isolators and they started discussing natural frequency and harmonic frequency and static loads and dynamic loads. They pretty much sent me to the showers.... I have some homework to do....

Yep, lower Db's/NVH https://www.vibracoustic.com/en/product/active-hydro-motor-mounts/

 

[Techmitch]

I saw those; earlier today I contacted the Lord Corporation https://www.lord.com/products-and-solutions/vibration-and-motion-control/industrial/isolators and they started discussing natural frequency and harmonic frequency and static loads and dynamic loads. They pretty much sent me to the showers.... I have some homework to do....

Replacing your generator engine mounts is probably the quickest/easiest/cheapest/most cost effective solution as somebody has already done some engineering to select what's there. I'm assuming yours are original??

In my mind, those compressor pads are an easy next step as they are designed to decouple a compressor (very similar to a small engine) of about the same weight and rotational speed, which would be a couple factors in selecting appropriate isolators.

Unless you have access to some vibration analysis software or skills in that department, you're probably just as well of using some trial and error.

Unless you use these pads on both sides of the plywood with a large bolt hole, you won't be isolating much at all. Like Tom said, the uncoupling is key. No direct metal to wood contact at all. My 21 KW Kohler has under water exhaust with venting through the port exhaust. From outside it sounds like a hair dryer on the lowest cool setting but when in the salon it is more than noticeable. This is going on the shorter list of updates for sure. In my case the frame on the genny is bolted directly to the hollow fiberglass stringers which I think amplifies the harmonics. I have about 10 inches of head room so installing isolators will be easier in my case. I think I will get some of the McMaster-Carr 1/2 inch bolt units. I had not ever considered looking there for isolators. This type would be ideal for further isolating the freshwater pump as well. Some dufus attempted to quiet mine down by screwing the pump to a stringer with a chunk of white Flexible PVC hose as a cushion.
Carpe Diem

Those compressor pads are through bolted and are not really isolating unless I'm not seeing the pic correctly.
If you want to get down to the heart of the matter
https://www.google.com/search?q=ele...=X&ved=2ahUKEwiGz5fgw_r1AhUaj4kEHY_WCcYQ_AUoAXoECAIQAw&biw=1280&bih=616&dpr=1.5

 

[Techmitch]

True isolation is key. Here's one of may sources. https://www.gmtrubber.com/anti-vibration-mounts/