BCS 735 doesn't start anymore

   / BCS 735 doesn't start anymore #1  

Pam62

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May 16, 2022
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5
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BCS 735
Hi all, I recently bought a BCS 735 petrol tractor. I used it for about 5 hours and it worked fine. Also started at the first pull.
Then it started leaking petrol at the connection beteren upper and loser part of the carburetor. The basket (old paper like) was drawn in. I slightly modyfied it and put it together again. The leakage was fine, it started ok, but stopped by itself after 20 minuten. This repeated 3 times. Now it barely starts, runs a few rounds and backfires.
Because of the history I suppose the problem is in the carburetor?
Sucking in false air because of gaskets? But I'd expect it wouldn't have run that long.
Dirt in the fuel? Any other reading or things to check?
 
   / BCS 735 doesn't start anymore #2  

lnk

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Feb 24, 2014
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327
Location
E TN
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Ferguson to-20, Deutz D7007, Yazoo yhr-60, Gravely 5240, Gravely C8 and model L,
Hi all, I recently bought a BCS 735 petrol tractor. I used it for about 5 hours and it worked fine. Also started at the first pull.
Then it started leaking petrol at the connection beteren upper and loser part of the carburetor. The basket (old paper like) was drawn in. I slightly modyfied it and put it together again. The leakage was fine, it started ok, but stopped by itself after 20 minuten. This repeated 3 times. Now it barely starts, runs a few rounds and backfires.
Because of the history I suppose the problem is in the carburetor?
Sucking in false air because of gaskets? But I'd expect it wouldn't have run that long.
Dirt in the fuel? Any other reading or things to check?
Sounds like the needle is not blocking the fuel when the bowl fills. Is the plug wet? Disassemble and clean the carb. Count number of turns in on needles before removing them so you can put them back to the same setting. (Screw in until it stops with light pressure while counting). Gaskets can be made. Hope this helps.
 
   / BCS 735 doesn't start anymore
  • Thread Starter
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Pam62

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May 16, 2022
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BCS 735
Thanks for the help! Had time today to work at it. Spark plug was completely dry. It night be that the problem arose because the field tank was "empty". I noticed today it takes it fuel from the front site of the tank. Leaning backward the fuel level propably was to low.
Now it starts.. but doesn't run smooth. Changes rpm, backfires and stops. Have to clean the carb.
Another question: allready from the start the axle from the gasvalve had some play. So rpm changed smoothly by the trembling of the engine. I put a tiny piece of rubber hose around the axle. That removed most of the play on the valve but the valve doens't run completely smooth. Could that be the reason for the symptoms I now have?
 
   / BCS 735 doesn't start anymore #7  

cmyoung2

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Jun 21, 2010
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North west NC mountains
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BCS 850, Kubota BX2230 w/FEL, mid mount mower, 41" tiller
Nice when it is an easy fix, but the easy stuff is sometimes challenging to figure out.
 
   / BCS 735 doesn't start anymore
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Pam62

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BCS 735
Episode 2: after one afternoon working in the field it again wouldn't start.

During the past weeks I did the following things:
* Clean it again (and again, and ..)
* Replace gaskets.
* Adjust level of fuel in bowl acc. manual.
* Checked working of spark plug: it sparks!!
* Checked contact breaker point distance.
* With removed air inlet and loose carb blew into the inlet with a compressor which shows a slight fuel plume from the middle pipe.
* When starting a few times fuel drips out of the air inlet (without filterappendage)
* When I pour some gasoline in the cylinder and put the spark plug in it runs for a few seconds.
* Sometimes when I start it backfires to the air inlet. Will later place a video of it.

What causes the backfiring?
As it runs with fuel in the cylinder does this mean it doesn't start because it gets not enough fuel?
If everything is cleaned what could be a cause of not getting enough fuel?
 
   / BCS 735 doesn't start anymore #10  

m7040

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Sep 15, 2006
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684
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Frederick maryland
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Kubota M7040, MF 203 industrial, ZD331, RTV 1100 , Kubota Minix excavator, Unimog 404
Also check the fuel float for leaks. That is a know issue that will mess up the fuel level in the carb
 
 
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