Hot engine starting issues

Roy Ale

Member
Oct 20, 2020
33
9
8
Victoria BC
My car with a 307 starts well when cold , but has always had issues restarting when the engine is hot , and now we are into above average summer temperatures . The car will restart but runs rough and takes a while for the engine to sort it self out . So cannot restart and just start driving , i have to wait until it sounds normal or it will stall , and i will be into another restart . To make sure the engine has less issues restarting i lift the hood when i get somewhere to let the heat out . and when i get home i lift the hood to let the heat out . So any ideas what i can do to have less hot restarting issues ? or no hot engine restart issues ?

Part of problem may be ethanol in the fuel , i see on internet ethanol boils at 180 F
have turned the air cleaner up side down , this has helped a bit , maybe it lets boiling fuel vapour out . have disconnected and plugged off vacume hose from carb to charcoal canister the other hose goes to fuel tank this i think may reduce sucking in fuel vapours from tank .
next thing would be replace carb gasket with something that reduces heat transfer to carb.
Carb is a Rochester QuadraJet with the Hot air tubes to choke
 
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Olds 307 and 403

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Oct 4, 2018
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Melville, Saskatchewan

Roy Ale

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Thread starter
Oct 20, 2020
33
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8
Victoria BC
Melville thanks thats a good tip .
was told the R. Q. has a small float bowl so fuel boils off faster than other carbs
I have the cast iron # 17 intake .
would the A4 aluminum intake help at all to reduce heat soak to carb ?
Does the # 17 intake have exhaust gas passages under carb to heat carb ? if the # 17 does , should i plug them off ?
Does the A4 have exhaust gas passages under carb ?
I think the exhaust gas passages under carb help the carb from icing up in winter time , but do they over heat carb in summer ?
 
Last edited:

Olds 307 and 403

Active member
Oct 4, 2018
760
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Melville, Saskatchewan
You need the crossover for the hot air choke to work. You could use an A4 which should run slightly cooler and block the intake opening with a piece of flat plate stainless steel. This will require conversion to an electric choke coil. The proper way to block the crossover is remove the heads and valves. Then pour molten zinc or aluminum to fill the crossover ports. A lot of work, more than you probably want. The thin stainless plate should keep some heat out, along with the thicker gasket under the carb. Good luck.
 

Roy Ale

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Thread starter
Oct 20, 2020
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Victoria BC
i have the hot air tube choke , it works fine , if i put in the thicker gasket .325 ( 8.255 mm ) and a stainless heat shield plate . The hot air tubes will not be long enough. So options are ? could i bend what i have to fit ? make new longer tubes for the hot air tube choke . Or change to an electric choke or a divorced choke or a manual cable choke . The manual choke sounds simple , no wires , no tubes ! is there an ideal best choke ?
 

Olds 307 and 403

Active member
Oct 4, 2018
760
230
43
Melville, Saskatchewan
The hot air choke needs flow from the crossover or it will stay on. Go electric, either splice from the distributor connector or the ignition terminal in the fuse box. A manual choke sucks in my opinion.
 

Roy Ale

Member
Thread starter
Oct 20, 2020
33
9
8
Victoria BC
So that i do not have to lift the hood every time i stop , i removed the big long rubber seal that fits on a metal edge at top of fire wall . The rubber seals off the engine bay from the cabin air intake when the hood is closed . When removed it sure lets the heat out. But when i turn on the vent fan or AC its not good , as car then has engine bay smell . This idea only works if i put windows down and do not turn AC or vent fan on . But might work if i could put a rubber seal only around the cabin air intake.

other ideas to let heat out with out lifting the hood , Oldsmobile hood vents or ram air dual hood scoops on the 442 . Any ideas about hood vents for a 4 door delta 88 ? or would hood vents look to out of place on a 4 door car !
 

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