BCS 735 doesn't start anymore

[Pam62]

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?

 

[Lnk]

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.

 

[joecoin]

New spark plug also. Just because.

 

[Pam62]

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?

 

[Pam62]

Fixed it: fuel filter was completely full.

 

[Spanner]

Phew!

 

[cmyoung2]

Nice when it is an easy fix, but the easy stuff is sometimes challenging to figure out.

 

[Pam62]

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?

 

[Pam62]

As promised: http://zhonglong.nl/pics/BCS735 start.mp4

 

[m7040]

Also check the fuel float for leaks. That is a know issue that will mess up the fuel level in the carb