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gleiwitz

Dellorto petrol pump - issue

14 posts in this topic

Posted (edited)

Hello,

I would like to ask for your help before I order a new petrol pump. Maybe I missed something during my investigation.

The problem with my Sherco St 300 from end of 2013 is that the carburetor does not get fuel or gets too little.

I first checked the vent of the fuel tank - one-sided valve ok,  fuel hose - ok,  fuel tap - ok.  Just to be sure I started the engine with the unscrewed fuel tank to be sure the reason was not to vent the fuel tank

I disassembled the fuel pump -  cleaned - I have not seen any signs of wear or damage.

I started the engine. After a while the fuel stopped flowin. I disconnected the fuel lines and fed the fuel directly to the carburetor using a syring. From disconnected fuel supply line from the pump to carburetor fuel does not flow. During engine operation in a normal situation petrol pump should pump fuel  ?

Do you have any ideas what else should I check?

 

Edited by gleiwitz

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43 minutes ago, gleiwitz said:

Hello,

I would like to ask for your help before I order a new petrol pump. Maybe I missed something during my investigation.

The problem with my Sherco St 300 from end of 2013 is that the carburetor does not get fuel or gets too little.

I first checked the vent of the fuel tank - one-sided valve ok,  fuel hose - ok,  fuel tap - ok.  For sure I started the engine with the unscrewed fuel tank to be sure the reason was not to vent the fuel tank

I disassembled the fuel pump -  cleaned - I have not seen any signs of wear or damage.

I started the engine. After a while the fuel stopped flowin. I disconnected the fuel lines and fed the fuel directly to the carburetor using a syring. From disconnected fuel supply line from the pump to carburetor fuel does not flow. During engine operation in a normal situation petrol pump should pump fuel  ?

Do you have any ideas what else should I check?

 

Pump works by vacuum  created by piston downstroke  so check the vacuum pipe that goes from the carb intake rubber area to the pump itself.....if it has a cut/hole in it or is trapped/pinched somewhere then you have no vacuum and therefore no pumping will take place.

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2 minutes ago, oni nou said:

Pump works by vacuum  created by piston downstroke  so check the vacuum pipe that goes from the carb intake rubber area to the pump itself.....if it has a cut/hole in it or is trapped/pinched somewhere then you have no vacuum and therefore no pumping will take place.

Thank you very much for the reply!

I checked the hose only visually. I did not dismantle it.  I checked its position so nowhere is trapped / pinched. I will check tomorrow whether there are any holes or cracks.

Apart from the vacuum pipe, something may be the reason for not creating a pump-induced depression? 

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5 minutes ago, gleiwitz said:

Thank you very much for the reply!

I checked the hose only visually. I did not dismantle it.  I checked its position so nowhere is trapped / pinched. I will check tomorrow whether there are any holes or cracks.

Apart from the vacuum pipe, something may be the reason for not creating a pump-induced depression? 

Yes a hole or non sealing of the diaphragm in the pump itself.

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3 minutes ago, oni nou said:

Yes a hole or non sealing of the diaphragm in the pump itself.

 Thank you very much for your help.

I will check it and if vacuum pipe will be ok  then I will order a new pump because I am slowly losing patience :)

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2 minutes ago, gleiwitz said:

 Thank you very much for your help.

I will check it and if vacuum pipe will be ok  then I will order a new pump because I am slowly losing patience :)

Hope you find the problem soon.

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A friend had the same problem, I think it was a kink in the pipe when reassembling the bike.

 

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Or dirt blocage into fuel tank tap. 

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Thanks a lot guys for all tips. 

I will check the vacuum pipe carefully today. Just to be sure I will put on a new pipe and we will see :) 

 

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breather pipe from carb too long gets clogged with mud, sherco known for it,

 

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Problem solved :)

The cause of the problem was vacuum pipe. It was not visible but when  I disassembled the vacuum pipe I noticed that hose/pipe clip was badly mounted at the very end which caused the hose to deform and consequently leak / catch the air.

 I mounted a new vacuum pipe on the lef side of carburetor where I my opinion is more space and pipe will not bends

79f89d49fae56d28med.jpg

 

Thanks a lot for your help.

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Today I was practice and unfortunately the pump stopped working again :( I got upset and ordered a new pompe. I hope this will resolve the problem definitively.

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Posted (edited)

17 hours ago, gleiwitz said:

Today I was practice and unfortunately the pump stopped working again :( I got upset and ordered a new pompe. I hope this will resolve the problem definitively.

 Voodoo type problems.

Edited by oni nou

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Heheh It will be funny when I will instal new pump and it turns out that it still does not work hehehe

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