Does your truck have the Mikuni carb? If so, these diagrams of the Evaporative emission system and its components should help:
With the Mikuni, likely sources of fuel in the cannister are a failed bowl vent valve or a stuck float needle valve. If either of these are the cause, a rebuilt Mikuni, or better yet, a Weber is the best fix
I believe it has the Mikuni Carb. I really appreciate the information you provided, It seemed like a wild goose chase trying to find those schematics.
I’m going to rebuild the carburetor to be safe from all ends regardless but I noticed today that the vapor line going to the tank was dripping today and I ziptied it shut temporarily. I’m wondering if there are any causes from the tank that I should be wary of?
The Mikuni is a nightmare to rebuild. Plus the only available rebuild kit doesn't include all the parts you need. Get a Weber from Redline or other distributor that sells "made in Spain" carbs. Don't buy a cheap Chinese knockoff. Do a search of this site and you'll find stickies and many, many threads that describe the benefits of a Weber, advise what to buy (carb, electric fuel pump) and how to install them.Originally Posted by Ram50Guy01
In the meantime, plugging the canister line should work. Many web sites or blogs blame a flooded canister on over filling of the tank or thermal expansion. Not sure if that's possible with these trucks, but if it is, keeping the fuel level to less than 3/4 might stop or slow the flow to the canister.
Alright, so I fully closed off the ‘to tank’ vapor line. My truck ran just fine and idled perfectly, where as the carb was bone dry and the truck was unable to start beforehand. My uncle informed me the previous owner had it closed off to begin with and that he actually reattached it to the canister. Do you think it’s still something to do with the carb? Someone else said something about a possible clog in the overfill limiter tube of the gas tank.
The overfill limiter valve may be stuck open thereby allowing vapor or fuel to flow to the cannister. Keep the tank line closed at the cannister and continue to drive it. If the carb has issues, the truck will drive poorly and mileage will be terrible. But since it seems to drive fine and if it continues to do so, there's no need to rebuild or replace carburetor. Driving it is the best test and it will reveal if something needs to be fixed or not.
Have fun.
Alrighty, will do. Thanks for all the info! I’ll take a few days of driving it around and provide an update afterwards.
Alright, so as an update. Pinching off the line has resolved my issue for now. I’m going to check the overfill limiter soon as I’ve been planning to drop the tank to clean it anyways. I’ll provide an update on what I find when I get around to it. I really appreciate the help and information.
Could you point me in the direction of the proper rebuild lit for the Mikuni carb or even a new or rebuilt Weber if you think that’d do better.
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