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10-31-2021, 11:35 AM | #21 | |
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Re: Engine sputters and dies when at high rpms and under load
Quote:
so if you have good flow at the line into the carb but not at the carb drain then it most likely that the problem is inside the carb.
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10-31-2021, 11:52 AM | #22 |
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Re: Engine sputters and dies when at high rpms and under load
Points too close.
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10-31-2021, 03:19 PM | #23 |
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Re: Engine sputters and dies when at high rpms and under load
If you get good flow with the bottom of the carburetor off but dribbles when the drain removed then it is likely that the float is hanging up. Take the carburetor off and shake it up and down and turn it over to check to see if the float moves freely. If not then take it apart to see if you can figure out where it is hanging up.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
10-31-2021, 04:11 PM | #24 |
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Re: Engine sputters and dies when at high rpms and under load
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
10-31-2021, 06:40 PM | #25 |
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Join Date: May 2010
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Re: Engine sputters and dies when at high rpms and under load
You said you used brake clean to check for vacuum leak and it slowed down? I don't think brake clean burns. Better try something else, maybe propane.
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10-31-2021, 06:57 PM | #26 |
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Re: Engine sputters and dies when at high rpms and under load
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Your say your points gap isn't adjustable. You should be able to adjust it. What is the measurement of the gap you have now? Pull the fuel line off at the carburetor and test the flow at that point. While you have it pulled free from the carburetor look to see how much of the fuel line sticks out past the ferrule. If it sticks out too far it can push against the fuel filter screen in the carburetor causing a lack of flow. When you sprayed around the manifolds the engine speed didn't go up but went down. Just the fact that it changed speed when you did so it points to a leak in that area. Leave the condenser in place when running the car. Swap it out for a new / different one instead. You got to go for a test drive or two before March to make sure it's fixed!!
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10-31-2021, 07:20 PM | #27 |
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Re: Engine sputters and dies when at high rpms and under load
I had a similar problem where my engine started and idled just fine, but when I revved the engine to higher RPM's, it sounded like it was choking (starving for fuel?) and if I kept the accelerator pressed down, the engine eventually started to back fire (quite loudly).
I tried all of the things mentioned above with no success. It turned out that my spark plugs were fouled (and possibly shorting at high RPM's). Once I thoroughly cleaned them and especially cleaned (and lightly sanded) the electrodes and then re-gapped them.....everything now runs perfectly. Brad in Maryland |
10-31-2021, 08:43 PM | #28 |
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Re: Engine sputters and dies when at high rpms and under load
the problem with the modern points is. good quality points are hard to find. most of them now have a plastic follower instead of the bakelite type. the plastic follower is rivet to the point spring and will cause a point of high resistance which will melt the plastic follower which will close up the point gap. i have changed so many of these junk points that now i will never put in a modern points plate. the original style point work just fine.
look at the points follower and see if it is plastic and if it is still intact, if they have melted and tightened up the point gap up throw them away and see if you can locate a good set that have the hard follower or change back to the original style points.
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old ugly my old father-in-law told me. "listen close when people tell you how to do stuff they may know something. then do it the way you want." |
11-01-2021, 03:22 PM | #29 |
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Re: Engine sputters and dies when at high rpms and under load
If your rpm changed with brake cleaner you have a vacuum leak!
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11-01-2021, 05:49 PM | #30 |
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Re: Engine sputters and dies when at high rpms and under load
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11-02-2021, 06:33 AM | #31 | |
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Re: Engine sputters and dies when at high rpms and under load
Quote:
I know that there's a small leak at the throttle shaft, but I'm still not sure if the manifold has a leak to the block because some of the bc-spray gets sucked in by the carb as well. Guess I'll have to check again with a short hose connected to the carb to make sure. Why it should only occur at higher rpms/load is something that's beyond me though, I doubt the manifolds heat up so fast that a crack would open up. Anyway, first on the list is flow testing the jets and changing the float valve. |
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11-02-2021, 06:38 PM | #32 |
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Re: Engine sputters and dies when at high rpms and under load
What is the measurement of the points gap?
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Dave / Lincoln Nebraska |
11-03-2021, 07:59 AM | #33 |
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Re: Engine sputters and dies when at high rpms and under load
Beg, borrow or steal (ok, don't steal one) a known good running carburetor and put on your car and see what happens.
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11-04-2021, 01:33 AM | #34 |
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Re: Engine sputters and dies when at high rpms and under load
Hi, where are you located? I have some flow tested working carburetors here. We could do some road tests next spring.
Cheers Michael
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11-04-2021, 06:26 AM | #35 | |
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Re: Engine sputters and dies when at high rpms and under load
Quote:
Hi Michael, thanks for the offer, I've sent you a pm. To everyone else, I'll report back after checking the jets. Greetings, Daniel |
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03-19-2022, 10:52 AM | #36 |
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Re: Engine sputters and dies when at high rpms and under load
Update:
Last week I ordered a new float valve for the carb and installed it. The first test drive today was promising: It can now run up to around 45 mph without stalling and doesn't stall even when climbing a hill with ~10% with mid rpms in 2nd gear. (~15-20 mph) I did notice however that the ignition advance lever didn't make a lot of difference. It is working, as I can feel the engine start to knock when I advance while idling, but there's not much difference on the road whether it's on 10 o'clock or fully pulled down. So I'll check the timing tomorrow, maybe it's a bit retarded. The torque at low rpms is good as it pulls away from a standstill nicely. As soon as I reach said 40 to 45 mph it just stops accelerating and starts to sputter, I think through the muffler, from time to time. Also when running the carb dry to park (at ~1000 rpm I'd guess) the engine runs normal but just before it dies the revs climb noticably for maybe 1 second. Am I right that it's still running too rich on at least the main jet and possibly also the others? GAV was completely closed by the way. Haven't flow tested the jets yet, that's next on the to-do-list after an oil change. |
04-29-2022, 10:01 AM | #37 |
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Re: Engine sputters and dies when at high rpms and under load
Another update:
In the meantime I disassembled the carburettor and flow tested the jets. Main and cap jet were relatively fine, with the main being a bit too lean. (fixed that, now they have the proper flow) The comp jet flow was way too high, around tripple the normal flow rate. Soldered it up and tinkered with it until the flow was right. Now the car won't go past 35 mph, it seems to run too lean. (getting lots of vibrations at ~30 - 35 mph without any backfire, no smoke as far as I could see) MichaelSchwarzer sent me one of his spare carbs for testing and the engines runs fine with that one. Top speed was ~55 mph (measured via gps) and it pulls nicely as well. That means it's definitely a carb-problem. I've noticed there are 2 differences between Michaels carb and mine: - the shaft of my throttle plate has a bit of play on the lever-side - turning the GAV on his car seems to make a difference compared to the one on my carb So I'll have to re-check the GAV on my carb, it seems to me that either the secondary well doesn't get enough fuel from the float bowl or the GAV won't allow enough fuel to pass to the cap jet. Is that the right direction or am I totally wrong? Thanks and have a nice day, Daniel |
04-29-2022, 01:21 PM | #38 |
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Re: Engine sputters and dies when at high rpms and under load
This just happened to me, ... in the end, it was the Armored Ingnition Cable shorting out when ever the vibrations got to much. Drove fine under 35 mph, or under 1300 rpm.
Regards Bill |
07-02-2022, 06:26 AM | #39 | |
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Re: Engine sputters and dies when at high rpms and under load
Quote:
Thanks. Newbie Rich |
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07-02-2022, 07:06 AM | #40 |
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Re: Engine sputters and dies when at high rpms and under load
Please explain what you mean when you say you have a split fuel. I have one line exiting my fuel tank that feeds directly into the carburetor.
Do you have access to a Zenith carburetor that is known to be working properly? I would remove your existing carburetor and try running with the Zenith. It appears the carburetor you have been using has some internal flow problems at the higher flow operating range. As someone has mentioned you are starving for fuel at the higher engine speed range. |
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