1970 cutlass, a couple of days back I floored the accelerator and shortly after that the car started sputtering and wanting to stalled and wont turn on, cranks but wont start? Help!


Asked by Mar 23, 2014 at 02:37 PM about the 1970 Oldsmobile Cutlass Supreme

Question type: Maintenance & Repair

Spark plugs have carbon residue and
also gasoline, carb is also running

16 Answers


How many miles on the engine? Not a good sign. Lifters, push-rods, and rocker arms fail at around 100,000 on the Olds rocket engines. You may be looking at getting the heads re-done. That's worse case.


Oh man this engine has gone over 900, 000 miles, but this has happened before and it has worked fine but it I floor the gas it happens again I just want to know what the problem is?


On an engine with that many miles, I wouldn't rule anything out. Have you performed a compression test on the cylinders? Checked for vacuum leaks at the intake manifold or base of the carburetor?


When was the last timing chain replacement? Who knows, the chain could of skipped on of the sprockets throwing the top end out of timing. If you said it happened after jumping on the throttle it's a possibility.


Another thought, check the distributor and make sure the drive gear at the bottom didn't skip under load. I've seen distributors "walk" up the gear and jump out of place if they're not bolted down.


No tests have been donde to the car but now I know which tests to do, thabks for the info, tomorrow i'll get back to you and thanks, im only 17 so I need practice.


What do you think about a bad carb or a bad fuel/air mixture?


If you have access to a timing light, I would start there if you can keep it running. Good luck!


Also when I started the car and put it on drive it stalls, I have to do that a couple of times and when I stepped on the gas it stalled too, maybe too much gas entering the carb and not igniting so the engine floods?


Air/fuel ratio.. possibility. Again, your dealing with a lot of variables with an engine that old and with that many miles. Have you tried starting fluid in the carb? I wouldn't recommend going too crazy with it in case there is a bigger issue. You don't want to slam any valves and start busting things up if there is a top end problem.


The way your describing it, it sounds like it may be a vacuum, timing or carb issue.


You said your plugs are dark and wet.. This indicates an extreme rich mixture.


Thanks for all your help, i'll start to work on the car and tomorrow I will update this, you're of much help!


If you have any other thoughts let me know!


I'm thinking timing chain/gears. I've had that happen doing exactly what you did. Could be a bunch of other things too, but most of what's been discussed here occurs more gradually. Having said that, with that many miles it could be anything. Let us know.


Take a 1/2 inch breaker bar, and a socket and put it on the crankshaft bolt, turn the crank, if the crankshaft moves 1/2 inch or more, the timing chain is worn. Replace timing chain. You can also check for a stretch timing chain by using a timing light. If the timing marks on the crankshaft drift back and forth. The chain is bad. Check the vacuum advance on the distributor with a vacuum gauge, the vacuum advance should move when vacuum is present. Check the float setting in the carb. You can buy a reman, or rebuilt it yourself. Grasp the distributor and see if you have excessive movement in the bushings. I would do a compression test first. 120 lbs or less is weak. Do a cylinder leak down test too.

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