Boat Emissions

[Prophammer]

Tinkering around with my new boat I discovered it as emissions devices on the gas tank , now I realize I have a Pressure Vent system with no carbon canister. Parts in the system are; tank inlet fill/check valve, vapor vent check valves consisting of 2 diurnal vent valves ;1 of each is mounted on each end of the tank (from bow to stern),, the diurnal valves have 2 functions internally ; closes vapor vent to stop overfill, allows venting of vapors during the diurnal process using vented gas cap. The fill the fill inlet and vent port are both together under the gas cap, I have no remote external vent and as mentioned before- no carbon canister. I found a lot of useful information on http://bluskies.us// I had a hard time figuring out how my tank works, I hope this helps someone else figure their's out !

 

[QBhoy]

Very interesting. Haven’t heard of this. But how would the fuel tank have a bearing on emissions ? Or am I being silly ?

 

[dingbat]

Very interesting. Haven’t heard of this. But how would the fuel tank have a bearing on emissions ? Or am I being silly ?

fuel vapor retention......aka air pollution

https://www3.epa.gov/region1/airquality/gas.html

 

[QBhoy]

fuel vapor retention......aka air pollution

Ah. So stopping fuel vapour in the tank escaping ? You’d think it might not make a difference in the end...given it’s going to be escaping one way or the other. Might keep the fuel fresh though. I’ll need to look it up. Very interesting.

 

[GA_Boater]

It seals the tank so vapors aren't released when the boat is not running. Same as cars today with no open tank vent.

 

[dingbat]

Ah. So stopping fuel vapour in the tank escaping ? You’d think it might not make a difference in the end...given it’s going to be escaping one way or the other. Might keep the fuel fresh though. I’ll need to look it up. Very interesting.

Google evap

 

[QBhoy]

Google evap

Will do.

 

[Prophammer]

what drew my attention was I could not get the gas gauge to read full even though I couldn't squeeze one more drop of gas into the tank, I then opened my hatches and that's when I found these fore-mentioned devices and wondered what they are.Gas gauge problem is unrelated to emissions post , I'll start a new topic for that sometime.....