'68 Sudden Sputtering
Thread Starter
6th Gear
Joined: Sep 2016
Posts: 6
Likes: 1
From: North Carolina
'68 Sudden Sputtering
Hi everyone, ive got a problem thats not very uncommon and something ive diagnosed and fixed many times, many different ways, but this time the onset of the problem was new to me. I have a 1968 327/350 4 speed, took it out for a drive this morning after it has sat for about 2 months. Stopped at a gas station and filled up with 93 like always; then after driving for about 15 minutes it started sputtering out of nowhere, violently. It would lose 500-800 rpm each time it cut out. My question here is what angle do you guys think I should go at it with? Normally with a sputtering situation id start with things like, cleaning the carb, checking and/or changing spark plugs, checking timing, etc. But with this one being so sudden and so violent im wondering if trash or something in the tank has gotten sucked into a line, anyone ever had that issue? When I did the restoration about 6 years ago I put a new tank and lines on it, so they "should" be clean and free of rust.
So far in playing with it today I have tried pouring a little sea-foam down the carb while running, and changed all the spark plugs AC Delco R45's, with no change at all.
So far in playing with it today I have tried pouring a little sea-foam down the carb while running, and changed all the spark plugs AC Delco R45's, with no change at all.
Safety Car
Joined: Sep 2005
Posts: 4,226
Likes: 643
From: Orange County Ca
Could be dirty/bad gas. Try changing your fuel filter and run a can of SeaFoam through your tank.
Through the tank is different than through the top of the carb, which just goes straight through the carb. It doesn't go through the jets or internal passages.
Through the tank is different than through the top of the carb, which just goes straight through the carb. It doesn't go through the jets or internal passages.
Last edited by Sayfoo; Mar 14, 2021 at 06:39 PM.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
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could be the fuel filter, the needles and seat could be gummed up with varnish, the fuel pump could have died. I would eitther put an inline fuel pressure gauge in or pull the fuel line and route it into a bucket and see what kind of flow you get while someone is cranking it over. If thats good check the filter in the carb and may be consider a rebuild. If you dont use a fuel stabilzer things like this can happen
Race Director
Joined: May 2006
Posts: 18,740
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Why not eliminate ignition first?
Check condition of cap and rotor.
Check dwell.
Check timing.
Check for cylinder not firing by carefully pulling one wire at a time from cap.
Then go to carburetor.
Do idle mixture screws adjustment have effect on idle?
No cracked or disconnected vacuum lines?
Check condition of cap and rotor.
Check dwell.
Check timing.
Check for cylinder not firing by carefully pulling one wire at a time from cap.
Then go to carburetor.
Do idle mixture screws adjustment have effect on idle?
No cracked or disconnected vacuum lines?
Le Mans Master
Joined: Aug 2005
Posts: 6,541
Likes: 1,975
From: Temple Terrace Florida
If it is a stock set up, there are three fuel filters. One is in the tank, one is after the fuel pump before the carb and the last one is in the carb. Any one or all three could be clogged. Jerry
