I recently purchased a 1965 Corvette 327. It runs great, but when I shut it off, it runs on, sputters and then eventually will shut down. What causes this and what can I do to correct it?

Asked by Sep 07, 2015 at 01:11 PM about the 1965 Chevrolet Corvette Convertible Roadster

Question type: Maintenance & Repair

3 Answers


There's a couple of things that can cause the "dieseling" that you're experiencing. First, too low an octane fuel. These cars were designed to run on premium gasoline with an octane rating of 100 or higher. I'd suggest using a premium gasoline and a bottle of STP octane booster at every fill up. My '70 Pontiac Catalina used to do the same thing. That's how I cured it. Since your Corvette was made before 1971, unless the heads have been rebuilt, you'll need to run a lead substitute at every fill up as well. For around town, low speed driving, it's not as critical. But if you plan on doing any expressway driving, you'll need the lead substitute. Again, I always used STP Lead Substitute in my Catalina. An idle speed that's too high can cause dieseling, as well as an engine that's running to hot. But given the poor quality of today's gasoline and the lower octane available I bet a bottle of octane booster at every fill up will solve the problem. HTH. -Jim


Wow! What a car- yeah, what he said- but understand, you will have fuel problems trying to use pump grade modern gas, most of which has ethanol- and it could be that you might need to adjust or rebuild the carb- to cure the dieseling- sometimes an old carb will continue to drip even when the ignition is switched off- in short, everything must be perfect-

1 people found this helpful.

Not all gas stations in the U.S. of A. put in ethanal. Yes the older engines need work to run on todays available fuel. Correct on the old heads. The old leaded fuel protected the valves and valve seats from pitting. Unless you get new valves and valve seats, you run a chance of burning valves. Have the timing checked also and get the carb rebuilt and perhaps new jets. Better or hotter plugs may be called for along with a hotter coil. My 69 does this also, but I have high compression and am running dual quads. If you have a stick, leave it in gear and start to engage the clutch when you turn it off. That will stop the engine. If your cars has a slush box, leave it in gear, give it a little gas and turn it off. That will keep the engine from dieseling or running backwards. That should help for now. My first Corvette was a 1965 327. Really loved it but without A/C in So. Ca., we traded it in on the 69. Still have it.

Your Answer:


Looking for a Used Corvette in your area?

CarGurus has 15,124 nationwide Corvette listings starting at $4,499.


Chevrolet Corvette Experts

  • #1
    John Carson
  • #2
    Vincent Parker
  • #3
    Tom Demyan
View All

Related Models For Sale

Used Ford Mustang
296 Great Deals out of 39,978 listings starting at $1,312
Used Porsche 911
68 Great Deals out of 4,580 listings starting at $9,999
Used Dodge Charger
332 Great Deals out of 32,185 listings starting at $2,000
Used Mercedes-Benz SL-Class
63 Great Deals out of 2,900 listings starting at $4,930

Used Cars For Sale

2019 Chevrolet Corvette For Sale
3,209 listings starting at $49,356
2018 Chevrolet Corvette For Sale
1,704 listings starting at $48,914
2017 Chevrolet Corvette For Sale
9 Great Deals out of 1,887 listings starting at $41,800
2016 Chevrolet Corvette For Sale
3 Great Deals out of 759 listings starting at $37,888
2015 Chevrolet Corvette For Sale
626 listings starting at $37,336

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.