Engine rebuilt and smoking badly.

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Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Engine rebuilt and smoking badly.

Postby Megoto » Sun Mar 28, 2021 5:20 pm

Hey people, ho's it going? I finished rebuilding the engine in one of my 154's and got it fired up today. The problem is she is dumping black smoke out at all throttle ranges. Set the timing with timing light, tried adjusting mixture on Carburetor, has new air filter and lines and passages have been cleaned. I cannot figure it out. Only problem I'm having is my needle valve in my carb keeps sticking open allowing fuel to pour out when tractor is isn't running. Any ideas?

Eugene
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Re: Engine rebuilt and smoking badly.

Postby Eugene » Sun Mar 28, 2021 6:15 pm

Megoto wrote:The problem is she is dumping black smoke out at all throttle ranges. Only problem I'm having is my needle valve in my carb keeps sticking open allowing fuel to pour out when tractor is isn't running.
Excess fuel.
Carburetor float not set correctly and/or needle valve stuck open.
I have an excuse. CRS.

tst
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Re: Engine rebuilt and smoking badly.

Postby tst » Sun Mar 28, 2021 7:29 pm

do not keep running it, the fuel will wash down your cylinders walls and possibly damage them or pistons, fix your carb

feg7846
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Re: Engine rebuilt and smoking badly.

Postby feg7846 » Sun Mar 28, 2021 7:53 pm

Black smoke - Carb problem. Sounds like float sticking. Don't know if you rebuilt the carb, or maybe replaced the carb, but the new needle valves that they are putting in the carb, do not have metal tip. Some kind of composite material that is subject to sticking. Just rebuilt my carb on my 47 cub and installed the new needle valve. Had to take carb apart and use my old needle valve because new one was sticking. Just saying............

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Sun Mar 28, 2021 8:38 pm

Thanks for the quick reply folks I will look at the carb again tomorrow and yes I did rebuild it and yes the new needle has that composite tip.

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Mon Mar 29, 2021 5:53 pm

:lost: Ok so I replaced the Needle and seat with a known good one from an older carburetor I have for back up. Still have the same problem. So put the parts back in the back up carb and put that on. Same problem. So I took the carb off of my running 154 and put that on. Same problem so I'm not sure it is a carb issue. I'm guessing I did something wrong somewhere but all cylinders are testing at 118-121 psi on the compression test. I'm stumped

Bob McCarty
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Re: Engine rebuilt and smoking badly.

Postby Bob McCarty » Mon Mar 29, 2021 6:07 pm

Did you adjust the float height and drop?
"We don't need to think more,
we need to think differently."
-Albert Einstein

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Mon Mar 29, 2021 6:39 pm

Not on the one I took off the running tractor that doesn't have any issues.

Jim Becker
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Re: Engine rebuilt and smoking badly.

Postby Jim Becker » Mon Mar 29, 2021 7:38 pm

Recheck the firing order on your spark plug cables.

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Mon Mar 29, 2021 8:07 pm

Well I took a short video of what it is doing but I can't seem to add it. I rechecked firing order from distributor and it is correct.

tst
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Re: Engine rebuilt and smoking badly.

Postby tst » Mon Mar 29, 2021 8:45 pm

its black smoke or blue ?

tst
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Re: Engine rebuilt and smoking badly.

Postby tst » Mon Mar 29, 2021 8:45 pm

what color are the plugs when you pull them

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Mon Mar 29, 2021 9:51 pm

The plugs are now black. And the smoke looks black to me

Eugene
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Re: Engine rebuilt and smoking badly.

Postby Eugene » Mon Mar 29, 2021 10:33 pm

Miss firing on one or two cylinders will cause dark exhaust. Two plug wires on worn cylinders? Cross firing/miss firing inside distributor cap?

Check the air cleaner. Plugged up?

Ignition timing? Engine to ignition timing?

Pause, take a break. Start 100% engine tune up all over again.
I have an excuse. CRS.

Megoto
Posts: 30
Joined: Tue Feb 28, 2017 1:53 pm
Zip Code: 38225
Tractors Owned: 154 LO Boy and a Yazoo 34 PTO-W

Re: Engine rebuilt and smoking badly.

Postby Megoto » Mon Mar 29, 2021 11:15 pm

Man I just rebuilt this engine. That would suck but I'm stumped so I will look at everything again


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