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vapour lock ?

PostPosted: Sun Aug 09, 2015 9:30 am
by crackfox1
Hello, I have a 1980 monza with a 151 duke. I've. Recently rebuilt the varajet changing the electric choke, choke pull off and solenoid. I thought I had it sorted but it stutters to a halt when it gets hot. As soon as it cools down it starts up no problem again. Any ideas / information on this issue would be welcomed. Simon.

Re: vapour lock ?

PostPosted: Sun Aug 09, 2015 6:12 pm
by jim327monza
Simon, You may want to look at the screen in the gas tank. I had a similar problem where the car would run for a little while cut off sit for a 2 or 3 min and start back up run and repeat. My first thought was vapor lock. After tracing the fuel system, I found trash in the tank. AS i drove the car the fuel pump would pick up trash off the bottom of the tank, starve the carb,car shut off,trash fell to bottom of tank, crank the car, start over. May be something to look at.
Jim H.

Re: vapour lock ?

PostPosted: Sun Aug 09, 2015 6:47 pm
by cjbiagi
You may also want to try loosening the gas cap to make sure it is not a fuel tank venting issue. If it is truly vapor lock then I would start checking the fuel line from front to back and see if it is near any heat source. It may help to insulate the fuel line if you do find anywhere it is close to the exhaust or engine block etc. I am not familar with the 4 cylinder engines but many other ones also use a insulator between the carb and intake manifold. You may also want to check your heat riser valve in the exhaust if you have one to make sure it is opening and not causing the intake manifold to get too hot.

Re: vapour lock ?

PostPosted: Mon Aug 10, 2015 1:48 pm
by crackfox1
Thanks for your replies. I'm going to check out the tank, especially since the car has stood since 1992. I changed the carb filter after breaking down on my first trip out. It was clogged and solid. Cheers. Simon.

Re: vapour lock ?

PostPosted: Mon Aug 10, 2015 3:10 pm
by crackfox1
I'm guessing I have to drop the tank to check the gauze out as there's no way in through the trunk (hatchback). Thank you. Simon.