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Carburetor - Huffing above 45MPH
Posted: Wed Jul 12, 2023 7:12 am
by Rdinatal
Ok, ok, so it's not really doing drugs... Neither am I!!
On the 2nd drive I was able to confirm what I 'thought' I was hearing. With my right ear deaf, sometimes I think things are different than they really are. The best I can describe it is when accelerating at 45mph I hear multiple "HUFF" (not a backfire). The engine lightly skips a beat but continues to develop RPMs.
Under 45mph, smooth...
Is that the Governor I keep reading about?
Any high speed (yea, right) jet adjustment on the carb I should look at??
Re: Carburetor - Huffing above 45MPH
Posted: Thu Jul 13, 2023 7:05 pm
by ez8
How far out do you have your choke pulled when all this is happening?
On mine I have to pull the choke out about 1/4" to get it to run smooth. Air is getting in somewhere, but I can't detect from where yet.
Re: Carburetor - Huffing above 45MPH
Posted: Fri Jul 14, 2023 3:03 am
by Rdinatal
ez8 wrote: ↑Thu Jul 13, 2023 7:05 pm
How far out do you have your choke pulled when all this is happening?
Choke isn't out, this happens at temp.
Re: Carburetor - Huffing above 45MPH
Posted: Fri Jul 14, 2023 1:29 pm
by ashyers
Rdinatal,
It's possible it's the governor. You can test it in lower gears and see if the behavior is reproducible. A search will kick up a bunch of posts on how to adjust the governor if that proves to be the case.
I've also seen a low float setting cause issues that were similar to a poorly adjusted governor. Again a search will help you out there. I'd suggesting setting the fuel level "wet" if possible as opposed to just measuring the float height with the needle closed.
Andy
Re: Carburetor - Huffing above 45MPH
Posted: Fri Nov 10, 2023 1:33 am
by Rdinatal
It was the governor. Adjusted and no more huffing.
While troubleshooting it was revealed that two cylinders have really low compression. Not something that one wants to find...
Re: Carburetor - Huffing above 45MPH
Posted: Fri Aug 01, 2025 4:29 am
by Rdinatal
Rdinatal wrote: ↑Fri Nov 10, 2023 1:33 am
While troubleshooting it was revealed that two cylinders have really low compression (80psi). Not something that one wants to find...
Wanted to update on the low compression.
After some reading I decided to
- Change oil/filter
- Put Marvel MO in the gas and oil (cleaning ratio)
- Run for two tanks
- Change oil and recheck compression
The compression is now between 95-110psi. While not perfect, it's good. There's other items that need attention.
Re: Carburetor - Huffing above 45MPH
Posted: Sat Aug 02, 2025 6:09 am
by Cal_Gary
I have never done a compression check. Perhaps I should, based on your results.
Thanks,
Gary