Ive been reading through the various forums and came across one talking about more or less bypassing the multi chambered thing (technical name unknown) that is right behind the access door. Is there any benefit to this? I have a 72 Scout II with the 345 and I just dropped the tank to find all the hoses brittle and cracked so know would be the time for me to just plug them if there is any benefit. I was looking into an aftermarket tank and it only had a spot for the overflow line that goes up to the top of the filer neck. So I guess it's common on builds to bypass the part listed above. Any info is appreciated.
Open vs. Closed fuel system
- Thread starter jgoss79
- Start date
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
That part you describe is referred to variously as the "condensing unit", "liquid/vapor separator", etc. It is a component of the evaporative emissions system that works in conjunction with the charcoal canister in the engine bay and a vent hose arrangement to the carburetor.
Without a functioning ees system, the atmospheric vent system for the entire fuel system will be impaired to the point the vehicle will appear to run out of fuel unless the filler cap is removed to allow atmospheric pressure to equalize the interior volume of the tank. And it will be near impossible to add fuel to the tank, it's somewhat difficult even with an operational system on a Scout II due to the design of the fuel filler component.
Once you start "plugging" anything, then the operation of the entire venting system for the fuel tank/filler neck/carburetor is going to be scruud. The Scout II is no different in this regard from any other vehicle sold in the north American market after 1968, the ees is a federal requirement as an emissions device.
The ees system is totally passive, if it works properly there is absolutely no reason to eliminate or juryrig it. Why not simply refresh all the hose connections so that it simply works?
As a commercial business, we don't advocate the modification or elimination of any emissions system or component. Private individuals do so at their own risk.
Information regarding the servicing of the ees is contained in the appropriate service manual for the vehicle and was also distributed to the dealer base in the form of service letters for each model year as the systems evolved over time.
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
If the carburetor currently is installed is a non-oem mixer, then it won't have a connection for the vent line that goes to the charcoal canister. That is one reason many of the aftermarket carbs are not considered "smog legal" and are rated for "off highway use only".
The charcoal canister must also have a vacuum source applied, so two hoses would have run to somewhere on the top of the engine, one for a vacuum source, one for the carburetor vent .
Attached is a ees system diagram for a '73 sii, it's virtually identical to a '72 model, only the actual oem carburetor is different.
The charcoal canister must also have a vacuum source applied, so two hoses would have run to somewhere on the top of the engine, one for a vacuum source, one for the carburetor vent .
Attached is a ees system diagram for a '73 sii, it's virtually identical to a '72 model, only the actual oem carburetor is different.
Eric VanBuren
Member
The 72 emission system did not have a hose to the bowl vent. So you should only have 2 hoses on the canister even if it has 3 nipples. One to the metering vacuum nipple on the main vac tree and one to the nylon hose that runs back to the separator.
I have all new hoses in and the tank re-installed. When I took another look at the canister it does have two nipples. One going back to the separator and the other has been snapped off so no nipple to run a vac. Hose from. Would you happen to have a photo of where it is supposed to go to? I will buy a new fitting and put it on.