Try contacting Lacanne’s. I saw on Walleye Central they have a 20′ tiller listed with a 175 Yamaha. Hopefully that means someone is now producing a power steering system for manufacturers other than Mercury.
I found a uflex system for yamaha’s just released this year
My dealer is saying they can’t order a 150vmax with a tiller. So it would be custom and void warranty.
I’m not sure the extra cost for the 150 is worth it. Not looking for speed but thinking if I add a kicker and 5 batteries, the extra power might be better for cruising at 35 mph instead wide open for 35 mph.
Rumor has it that Yamaha only makes a tiller for up to a 115 and although it fits the 150 and 175 they do not stand behind it for whatever reason. I had a 2009 WX 2000T with a 150 and a tiller but it was a 115 tiller handle. Not sure why Yamaha fights the big tiller thing but they do. It will work and there are many out there just a liability thing for Yamaha.