Ercoupe gross weight STC possible?

He said he had a C-75 which uses a 73” prop, which is not legal on a C-85

Larry , explain the

"new prop" requirement.
I have the 85hp change and a McCauley 7150 prop which I bought new 3 years ago .

Thanks

Bill James

Chris, changing the trim tab from the original 3/4" to the 1 3/8" trim tab is all that is necessary on the 75 hp to raise the gross weight to 1320 lbs. Ref Univair STC SA02450CH. Far cheaper than buying a different prop. One can either add a trim tab extension (p/n 415-22031-4) or replace the entire trim tab (p/n 415-22031).

Pretty simple mostly paperwork and a new jet for the carb. Same engine, basically.

Thanks Larry, yes that was my next question... how involved is the C-85 conversion (aside from the prop)?
Any articles in Capers or on this site which can help?

It can be done. 1320 with a 75 is a little tricky, imho. You can always upgrade to a C-85. Of course that means a new prop…