I understand the Beta 38 is the go-to engine W32, but before I commit I just want to inquire briefly if any lighter and emissions Tier 4 EPA rated engines have been investigated by anyone? We have used the 1800rpm Kubota engine for some remote generator applications (-45C land based) with great success. 

Although I do not want to re-invent the wheel... just checking if any Kubota or Yanmar engines have been spec'd for a W32. Just trying to get the quietest/cleanest/ most fuel efficient engine currently available today.... perhaps those attributes are eclipsed by the tried and proven Beta engine experience by all thanks to Bud et'all.... as long as the Tier 4 requirement won't come to bite me.

Thanks in advance for any response.

Paul