I've had the vapor lock issue on my '06 21v since the first time I took it out brand new. I've now got a 2 year old and a 4 year old and this is the first year we've been able to start spending a lot of time on the boat as a family. I guess that's what made me realize this problem for what it is instead of an inconvenience. It's a safety issue. My boat was bad enough that it was a given that it would vapor lock if we let it sit for a half hour or more after running it. Nothing help, running the blower, leaving the cover open, etc. A lot of that is because all of the fuel available here is 10% ethanol and the lake we are usually on feeds a power plant so the water gets pretty warm. It hit me while we were anchored up and the kids were swimming. What happens if one of them gets hurt and I need to run back to dock in a hurry? The last thing I want to do is work on a vapor locked boat in that situation.
I finally just went ahead and bought the indmar secondary pump kit on skidim. Install isn't bad at all. It took me a couple of hours but most of that was figuring exactly how and where I wanted to mount it, not actually working. I mounted it right to the stringer on the port side just aft of the fuel tank. The biggest problem I had was space between the v drive and stringer. It's pretty much impossible to get a drill in there to start the holes for the mounting bracket. If you've got a drill that you can get an angle drive attachment for that would work. I've got a cordless impact driver which was just short enough to get the job done. The included bolts for mounting the bracket aren't ideal either. They are machine threaded so they're not made to hold well in fiberglass. I undersized the holes a little bit and they are working fine so far but I'll probably swap them out when I find some small lag bolts that are stainless or treated so they won't rust.
So far everything has worked great. Not a single problem since the install.