Vapor lock?

ledslinger29

Well-known member
Hey fellas! I've got about 150 miles on my new 170, I can drive it five miles or thirty and it runs great, but after I turn it off and run inside the gas station or the beer store it doesn't want to crank back up. After fooling with the gas pedal a bit it will start, but it doesn't want to, and it'll barely run for a few seconds, then if I can keep her up she'll run fine til I turn the key off again. What do y'all think? Etta only seems like a fuel problem, I'm running an 1100 with SCV.
 
:unsure: A few things to try. 1. Recheck that the float level is set correct and if it is lower it a little more. Make a insulator out of a plastic cutting board or seemular material or install a thick carb base gasket mid 1970's to early 80's 3.3. Insulate the fuel line. Good luck :nod:
 
I wish i had a photo, but build a heat shield under the carburetor to shield it from exhaust heat.
Also add another thick gasket under the carb to manifold.
 
guess ur gettin conformation on ur 'vapor lock' diagnosis. That's got the prob 1/2 solved. Good on ya mate! I understand our bronks have a "lack of air circulation prob under the hood". Don't know if it applies here but 1 after mrkt co. has louvered inner fender replacement panels as assistance.

'Back in the day' ('60s) some of the older kids in the neighborhood usta put close pins on the fuel line (not sure where, I was too young to follow the procedure) some put the 'gas line antifreeze' in the tank (that lill yellow or red plastic bottle of isopropyl). May B these are solutions for our humid climate situations only?

If it is 'vap lock' it comes from moist air rushing into the boar, the speed increasing the temp and the H2O freezin out to clog the narrows.

The fella's idea on 'spacer' is good. Bill's idea on 'heat shield' can B done from a good search of the junk yrd for that alu tin type metal modern cars use to shield the exhaust heat from the passenger's compartment. There are some Subarus that have some good sheets under there to scavenge. Any 1 know of an aftr mrkt source for those sheets (rather than scavenge from other applications) be nice to start from scratch?

Non Vap Lock:
Would some 'choke work' assist here? :unsure::
R the 'fingers' on the carb linkage setting up right for starting mode? When set right these i6 start up perfict w/no pump/flutter/etc on the peddle. (C Handbook 4 correct start proceedure). Is the carb bowl leakin out it's fuel as it sits for ur short hop-out-&-into-the-store?
 
Does water go thru your carb adapter?..It is made to warm and cool the carb.
Make sure the choke is working right .
 
I'm not seeing any fuel leaks, so I don't think the bowl is leaking. The choke is manual ( I like it ), and is set properly, with the plate vertical in normal operation. I disconnected the coolant line through the spacer per the handbook ( I live in Florida ).
 
ledslinger29":25r1eann said:
I'm not seeing any fuel leaks, so I don't think the bowl is leaking. The choke is manual ( I like it ), and is set properly, with the plate vertical in normal operation. I disconnected the coolant line through the spacer per the handbook ( I live in Florida ).
If it is not to hard ,hook it back up and see if it helps.
 
I'd agree~
it's not abt climate, cab heat, etc it's abt engine needs...
 
chad":1a750oxw said:
I'd agree~
it's not abt climate, cab heat, etc it's abt engine needs...
I disconnected it since the handbook said it wasn't needed where Im at, but ill hook it back up and see what happens. My understanding was that it was there to provide heat to assist with carb icing.
 
I had a similar concern with our 170 and it ended up being a weak fuel pump. Just another thought.
 
Howdy,

I had a similar issue but i'd get vapor lock while driving at slower speeds, under 30. I found out it was the carb boiling (Holley 1904). The water through the adapter would help that or do what I did, ditch it and go with a weber 32/36 with an insulator. I have a YouTube video explaining the basics of what you need to do and jet sizes, but its for a 200 but maybe a size smaller main jet possibly. Search the name StarDiero75 and you'll find it.

Good luck,
Ryan
 
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