If you want to clean them yourself you can get the baskets/filters for 50 cents each at fuelinjectorconnection.com. Tell them you have Denso injectors on a Yamaha outboard. Also to do it right you should be able to open and close the injector to allow fluid through. Ask the guy for the electrical pigtail that fits on the injector and then wire it into a 9volt transformer. 12volt will work but 9 is safer as you don't want to fry the injector coil. Get a button switch and then just click it open and closed as you push fluid through. But don't hold the injector open more than just clicking it open and closed so you don't heat it up and fry it.
I used a half inch clear plastic hose that fits over the end of the injector and then a hose clamp to secure it. I also got a air pressure regulator and a valve so I poured sea foam into the hose, hooked the regulator and compressor up, dialed up to 40 psi and cycled the fuid backwards through the injectors to clean them. With all the electrical junk I've bought over the years I have a box of the plug in charger transformers in my shop. I also got an ultrasonic cleaner that I also cycled the injector in while the bottom half inch was in the bath. The ultrasonic cleaner also cleans up the vst filters like new.
So you can see I set up a rather sophisticated system to clean mine which is what you need to clean them properly. But as the boat with the f115s was at the family place in Florida, and I only get down there for a few weeks a year, time was the biggest constraint. I was able to replace the VST filter and have the injectors cleaned with new filters by the end of my first day down. Then I was able to put a beat down on the grouper.
Good Luck
