71 Cutlass vapor lock?

Originally Posted by bullwinkle
There is NO evap system on the OP's Cutlass, the gas cap or tank normally has a small hole or orifice that is open to the atmosphere to allow excessive fumes out & air in during operation, which makes the fuel go bad faster than it would in a modern sealed system.

Are you sure? My 70 elcamino had a canister and related vacuum hoses.
 
If it helps, my MG had a big problem with vapor locking years ago. The engine wasn't overheating, but the mechanical pump would get hot enough I could take the cover off of it and hear the fuel boiling inside when it decided to stall out on the road a few times. Supposedly the '79 model had a thick spacer added between the pump and the block to better insulate it, but the pump had a different lever to account for the spacer. Since those later pumps aren't available, I put in an electric pump next to the tank and bypassed the mechanical pump.
 
Quote
Tell that to the general aviation guys.....

https://generalaviationnews.com/2011/06/26/vapor-lock-ethanol-and-ultralights-2/


These guys are talking about several different failures in the supply chain, and don't REALLY blame ethanol on the issue, just the failure of the rest of the system to comply with specs.
With Ethanol having an RVP of 2 psi, it will not increase the possibility of vapor lock in the sense that the OP is referring to.
Yeah, maybe at higher altitude, it may be an issue. I don't think the OP has flying car though.
 
I am burning through some fuel that i bought during the winter. I mixed a gallon of it for my chain saws. My smaller saw seems to be vapor locking on it. It runs great , and when shut off sputters to restart until if cools, it has spark, so i think i need newer fuel.
 
Originally Posted by spasm3
I am burning through some fuel that i bought during the winter. I mixed a gallon of it for my chain saws. My smaller saw seems to be vapor locking on it. It runs great , and when shut off sputters to restart until if cools, it has spark, so i think i need newer fuel.


That's a good start, trying some fresh fuel, preferably without ethanol if you can find it.
 
Originally Posted by wings&wheels
For your car, I would try and run pure gas but if you can only get e10 (like us), I'd use a good treatment/stabilizer. If it were my vehicle I'd use Sta Bil marine and a lead substitute.

Good luck.

Just a quick point here - GM lowered compression and added hardened exhaust valve seats to allow for unleaded fuel (91 Research octane which is 87 R+M/2 octane on today's US and Canada gas pumps) across the board for its 1971 models. No lead substitute should be needed for GM cars starting with the 1971 model year. Here is a page from a 1971 Buick owner's manual that confirms this:

http://www.oldcarmanualproject.com/...lark%20Owners%20Manual-Page%2063_jpg.htm

Enjoy that Cutlass - great cars.

Andrew S.
 
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