Needing a mud motor for moderately flowing river. I have a 14 x 48 john boat. What HP would you recommend and what do you run on your 14 x 48?

The biggest you can get. Anyone who says a boat can have too much giddyup is a quitter. Every boat should be a hydrofoil.

I have a 23 hp GoDevil. Has a Briggs and Straton motor. I chose the 23 hp over bigger because it has both electric and pull start. I've used it on a small river, 20 yds wide+/- , with heavy current with no issues. I had a new shaft, prop, bushing, and seals (all parts for the long shaft) put in. The dealer asked if this was the same motor he sold me over 20 years ago. Yep! I had it on a 14 x 48,but went up to a 16 foot for more room. I've driven bigger motors, but in my opinion had to much power. 23 is a great balance point

I run a 23 horse go devil on my boat 14 by 48 crestliner. Goes fast enough for me.

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The 23 Go-Devil is an excellent longtail and with excellent support !

Do you run that on rivers or just lakes?

I’ve had go devil and backwater. I prefer backwater in the long tails. Just bought gator tail surface drive definitely faster and easier to operate. Don’t pop out of the water tho

I have been on the Mississippi as well as a smaller river for quite a few years when I lived in Minn. The Crestliner I have is welded and heavy but if it's floating I'm going.

Maybe I'll upgrade the HP. Concerned to spend the money on a 23-24 hp motor and still not go upstream. I do appear to be the king of downstream, however.

You'll have no issue going up stream in a 23 hp. See if they will let you take it fir a demo. The small river I ran had really string current. I left my right side gif on my trailer attached with one bolt so I could push the hide down parallel with the trailer so I could float the boat over the trailer from the side to load it. Couldn't load it normal by yourself because of the current. Also ran the Mississippi River too..