I noticed another message by Patricia Wood suggesting Sherburn Furnald. He is your man. In 1852 he is in Huron, Des Moines, Iowa. Ira was in Pleasant Grove in 1860, which is also in Des Moines county. In 1840 Washington, Allen Indiana,Sherburn has 2 males 5-10 and 3 males 10-15, he is 30-40. There are 2 females 5-10 and his wife is 30-40.
The 1850 census (1852) of Huron, Des Moines, Iowa has: Sherburn Furner (Furnald) age 50 born in Ind? Martha 45, ILL? female Irull? 24 ILL? Nelson 20 ME Ira 16 ME Elmira 14 ME Clarinda 10 ME Jane 8 Ind Marshall 4 Iowa John 2 Iowa
I think the place of birth is wrong for Sherburn and Martha or may not be his 2nd wife, or her place of birth may also be misrecorded.
So now Sherburn is the brick wall!! I'll keep digging.