# Diagnose fuel pump; 16HP Vangard



## 40cpe (Jul 23, 2011)

I have a Cub Cadet 2265 that only sees occasional use. I last ran it about 2 months ago. I tried to start it today and it wasn't getting fuel to the carb. I took the fuel line off at the input to the fuel pump and pressurized the tank to be sure there was no restriction. It forced fuel through the filter and out the end of the fuel line. The engine starts immediately on starter fluid. While running briefly on starter fluid I could feel no vacuum at the input side of the pump. I THINK the pump works from pulses from the valve cover, but have no idea how to verify a bad pump or some other problem not letting the pump work. Any advice is sincerely appreciated.


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## jhngardner367 (Apr 5, 2011)

Connect the vacuum line,as usual,and leave the hose from the pump to the carb disconnected at the carb,and aim it into a container. Roll the engine,and see if it pumps, if not,replace it.
If you forced fuel through the pump,it may have damaged the diaphragm .
Briggs # 491922 ,or equivalent .


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## rcbe (Aug 26, 2015)

OP - one caution: If the starter fluid you used to test start engine is ether, lose it and use rattlecan carb cleaner instead. Ether can very easily damage an air cooled small hp engine...use that stuff for the big diesel engines.


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## 40cpe (Jul 23, 2011)

I disconnected the fuel hose at the INLET side of the pump to pressurize. I'm just wondering if there is a possibility/probability of something with the engine not providing a trigger to work the pump. Is there a way to verify that? The replacement pumps are cheap enough to try, but for the wait getting it here. Seems the pumps I find online are plastic, mine is metal.


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## jhngardner367 (Apr 5, 2011)

You can get the pumps at Walmart,or Lowes,garden centers,or at a auto parts store,usually.
The pump is operated by engine vacuum,from either the valve cover or a breather plate,or a fitting on the intake or engine block.
Pressurizing the pump usually damages the diaphragm,since it's actually 2 chambers.
In the vacuum side, the pulses draw down on the diaphragm,and draws fuel through a port,that has a flap.
As vacuum stops,a spring returns it to normal position,,which pushes the fuel out of the pump.
Putting pressure(anything over 3 psi) through either port (inlet/vacuum/outlet) usually causes the diaphragm to tear,or at least,deform,permanently.


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## 40cpe (Jul 23, 2011)

Thank you, I have one on the way.


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