" Loose Yamaha dealer" – translate please

I went to a boat dealer today and talked to them about a boat that normally comes with a merc. 90 or 115.
This dealer also sells and services two other brand boats that come from the factory with a Yamaha.
I asked – “can I get it with a Yamaha”, and whats the price? .
He said – no, cause we are not a “loose Yamaha dealer”,, plus he said you would need all new controls.

If they sell Yamaha new with boats, and of course service the engines that they have just sold (and I assume other yamaha walk in people with engines) why cant they sell a motor.

Or is it just two much trouble to take the merc off then they are stuck with a spare engine?

Thanks