Vapor lock?

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Hi everyone, I have been having some minor issues with what I think is Vapor lock. After heat soak the primer bulb loses its air gap and gets hard. My guess is either the carb diaphram or the gas cap. The idle seems to pick up. I am running the stock zenoah 32.
 
Sorry we all missed this.
It's definitely common for the vents to get plugged with dirt and cause a vacuum lock.

I recommend adding another tank vent for redundancy. I'm not sure what vehicle this is, but you can get tank grommet kits which come with everything you'd need to add an extra vent.
 
HXRC said:
Sorry we all missed this.
It's definitely common for the vents to get plugged with dirt and cause a vacuum lock.

I recommend adding another tank vent for redundancy. I'm not sure what vehicle this is, but you can get tank grommet kits which come with everything you'd need to add an extra vent.
Click to expand...
 
It’s a Dbxl 2. I had the issue from new, it would slowly start to lean out. My first guess was the carb diaphragm, there was no change after replacing it. I removed the small seal in the gas cap and it improved, but I think it still needs a little more vent. Thank for the input, good winter project.
 
Having the same issue with my brand new hpi baja. Car runs fine during engine break in then is starts to lean out after 5 minutes progressively getting worse. I am going to test shortly, but I was screwing the gas cap on as tight as I could and the last time I took the cap off the diaphragm inside was suctioned so right to gas tank it was so very pressurized. I am am thinking it is vacuum lock causing this bogging issue. I am going to put gas cap on pretty loose to see if that helps. I checked the cap does have the hole in it free and clear.
 
Highly recommend Taylor's caps , just make sure you get the right one.....threads on tanks are different. You're not gonna spend 20- 30 bucks on a better upgrade!!!!
 
Thank you. I will do research on caps! Confirmed it was in fact Vacuum lock. Cap is still suctioning down after running for a while I unstuck the diaphragm and it immediately was fine. Thank goodness it was only this. Diagnosing was perplexing to say the least. Hopefully others can learn from this post.
 
Been there, done that,.....I am far from an expert, but this group of people are great, intelligent, friendly folks. Just reading build threads has gotten me a ton of tips.
 
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