2000 Sundeck 210 Engine Venting

[boater2018]

As some of you have probably seen, I have had some vapor locking issues that I have been fighting. I had come to the conclusion that I just needed to get the booster pump kit and hopefully be done with it, and then I spoke to a mechanic yesterday (I don't think Mercruiser certified, but has a good reputation) about possibly routing the fuel return line into the fuel fill line and he asked me how I confirmed it was definitely vapor locking. I told him what all had been done as I have posted on here before and he said that I needed to replace the anti-siphon valve with a regular 1/4 npt to 3/8 barb fitting. He said it would not siphon the fuel out into the engine bay. He also said I needed to replace the fuel line from the tank to the fuel water separator with a "unlined" fuel line, recommended Gates brand. He is thinking I probably have an air leak somewhere either there or the pickup tube. He said the booster pump shouldn't be needed and it's just mercruiser trying to sell a product. I can't say that I can argue much as you would think vapor lock would be a problem since it was new if the design was really that flawed instead of just happening suddenly after years of use without having the issue. Anyway, I have seen mixed reviews on removing the anti-siphon valve and was thinking I would just replace it instead and the fuel line. I am nervous about messing with the pickup tube because it is one there super tight and the tank is poly, so breaking something would be a difficult fix. I am just posting this to see if anyone else has fixed vapor locking issues by replacing any of these items.

Also, I saw where an individual on here had the same model bowrider and fixed his be re-routing a vent line to the upper portion of the engine bay and he might have added a second blower, but can't remember about that. My boat has 4 vent hoses and none of them are directed to the top of the bay. It seems like that would discourage heat from escaping the engine bay. I looked around at some other 210 sundecks for sale and saw some that were similar to mine and some that had only 2 vent hoses. It made me wonder if someone removed 2 of them to try and help heat escape through the upper vents. Could it hurt anything to remove 2 of them? It seems like it would only improve ventilation.

I haven't had the severity of vapor lock issues this year as last season, but the water is getting warmer and I did have more issues last trip with it than I had yet this year. Thank you guys as always. Great forum!