my engine is coughing

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elmer
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my engine is coughing

Unread post by elmer » July 13th, 2018, 4:35 pm

Hello everyone. My A2 worked very well until suddenly it has started to cough when I accelerate. Only when it circulates. if accelerating without driving does not fail. I have checked spark plugs and distributor and I have cleaned carburetor and air filter but it still fails. I've realized that if I give the choke a little bit it works fine. Any idea? I don’t know what else I can check.
My carburator is a zenith 13669B
elmer
Last edited by elmer on July 13th, 2018, 4:49 pm, edited 1 time in total.

Hambone
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Re: my engine is coughing

Unread post by Hambone » July 13th, 2018, 4:41 pm

Coil or fuel filter??

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Re: my engine is coughing

Unread post by elmer » July 13th, 2018, 4:53 pm

My distributor is a swiss control model.

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Re: my engine is coughing

Unread post by Hambone » July 13th, 2018, 5:27 pm

The Swiss modules are very reliable, not saying they don't go bad, but yours sounds more like a coil, being you went through the fuel system. If you are confident with the fuel, I would suspect coil.

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Re: my engine is coughing

Unread post by Hambone » July 13th, 2018, 5:38 pm

Oops! you changed the original post, now I would lean toward fuel.

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Re: my engine is coughing

Unread post by elmer » July 13th, 2018, 6:05 pm

forgive me Hambone. is that I had used the word starter when I was really talking about the choke. It's curious because if I take the choke out a little(very little), the engine no longer coughs or fails to accelerate in each gear. I cleaned the carburetor and changed the fuel filter

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Re: my engine is coughing

Unread post by rickf » July 13th, 2018, 6:19 pm

Try resetting the idle mixture screw. You want to turn it in until it just starts to stumble and then turn it out until it starts to run a bit rough and then instead of going back to the middle as you would normally only turn it in from the rich side about a half turn and see what that does for you. If you do not seem to get any action when adjusting the screw it is probable that you got something clogged in the idle passage.
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Re: my engine is coughing

Unread post by elmer » July 13th, 2018, 6:27 pm

The problem I have with the iddle mixture screw is that my zenith 13660B carburetor has no screw in sight. It's the kind that has it covered with a stopper and I've never dared to touch it

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Re: my engine is coughing

Unread post by rickf » July 13th, 2018, 9:28 pm

And there is your problem, it will be set too lean. Carefully drill a hole just big enough to get the tip of a sheet rock screw jammed into the cap over the screw, chuck the drill as short as you can and take your time so that when it breaks through you do not damage the mixture screw under it. There is a little room there but no a lot. You will find that you can back out that mixture screw quite a bit before it gets to the rich side and then go in just a little bit. You can try the normal halfway between method but if you still have issues do what I said and go a bit on the rich side. Any carb that still has the emissions cap on it s going to run lean and 90% of them have the famous "flat spot" and the owners are always driving with the choke on.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

elmer
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Re: my engine is coughing

Unread post by elmer » July 14th, 2018, 7:30 am

Thanks rickf, I followed your advice and the engine has improved a lot. I have removed the cap cover on very careful but without problems and I have turned to the left the screw a whole turn. I've driven it and Engine almost doesn’t cough anymore. This afternoon I will try it longer. Do you think a lap is enough? I have to put the screw cap again or can I leave it without a cap?
Elmer

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Re: my engine is coughing

Unread post by rickf » July 14th, 2018, 8:34 am

You can leave the cap off, it was only there to keep people from adjusting the mixture against the rules of the emissions lords. Do not be afraid to experiment with the adjustment, you can't hurt it. To set it to the standard you would turn it in until the motor starts to stumble and then out until it starts to stumble counting the turns and then go back in halfway in between those two points. On the M-151 I have found that they run much better when you go out to the stumble and then in only 1/2 to 1 turn. But do not take that as gospel, start with that and go in a half turn more at a time after driving it far a couple days until you get the flat spot again and then back it out the half turn and you should be set for a good long time at that point. You can put a drop of nail polish in the hole to lock the screw but I never do and I don't have any problems. If for some reason it does go out of adjustment it is certainly easy enough to turn it a 1/4 turn if need be.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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Re: my engine is coughing

Unread post by acudanut » July 14th, 2018, 9:41 am

rickf wrote:And there is your problem, it will be set too lean. Carefully drill a hole just big enough to get the tip of a sheet rock screw jammed into the cap over the screw, chuck the drill as short as you can and take your time so that when it breaks through you do not damage the mixture screw under it. There is a little room there but no a lot. You will find that you can back out that mixture screw quite a bit before it gets to the rich side and then go in just a little bit. You can try the normal halfway between method but if you still have issues do what I said and go a bit on the rich side. Any carb that still has the emissions cap on it s going to run lean and 90% of them have the famous "flat spot" and the owners are always driving with the choke on.
Forgive my ignorance, but do you have a picture of what area of the carb you are talking about. I love pictures. :D

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Re: my engine is coughing

Unread post by elmer » July 14th, 2018, 11:57 am

Hi,hear can see the cap and the screw

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Re: my engine is coughing

Unread post by elmer » July 14th, 2018, 3:19 pm

I have been doing tests and many miles this afternoon to know if I could solve the problem of my A2. Regulating the screw has improved the problem of the engine and it does not fail so much but still coughing a bit.
I only have these failures when I accelerate to change gear and always driving (with the engine running but without moving the A2 there are no failures).
Elmer

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Mr. Recovery
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Re: my engine is coughing

Unread post by Mr. Recovery » July 14th, 2018, 3:57 pm

Sounds like the Advance Timing weights or springs are stuck or rusted. :roll:

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