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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14908
Experience:  Certified on Onan and Generac generators
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I have a Honda EX4500 generator. It ran fine earlier this

Customer Question

I have a Honda EX4500 generator. It ran fine earlier this year. I just moved, so I had to drain all of the gas. I went to fill it and start it. All it would do is start and stall. I checked the fuel into the carb, the solenoid is opening. If I hold the choke almost completely closed, it will run up to full speed. It seems that on start up, the choke will close. But as soon as it starts, the choke opens fully, and it stalls. If I bypass the temp switch, it will start and run, but then the choke doesn't fully open.
Submitted: 1 year ago.
Category: Small Engine
Expert:  Hank F. replied 1 year ago.

Hello, my name is ***** ***** I am going to assist you with this.

Thisis a classic symptom of a carburetor that has become plugged with varnish.

Asgas gets old, it turns to varnish and clogs up the passageways inside thecarburetor, not allowing enough gas to get to the engine.

Today’sgasoline formulation goes bad in as little as 30 days.

Thiscondition is cumulative. Every time gas sits, the varnish builds up just alittle more, like coats of paint, until eventually gas can notflow. It will not happen overnight, but the symptoms can show up allof a sudden, even while simply stopping to refill with gas.

Theuse of fuel additives, such as Sta-Bil or Sea Foam will not stop this processfrom happening. They will greatly slow it down, but the gas will still go bad.

Thiscan also happen even on a brand new engine or brand new carb. When the carb isbuilt, it is run at the factory to tune it.

Aftertuning, they do not always get properly cleaned, or may not have enough/anypreservative injected. Believe it or not, this is actually fairly common.

Whenthis happens, either the engine simply will not start, or it will not runwithout the choke on (this reduces the amount of air getting pulled into theengine, changing the fuel/air mixture), or it will run but surges.

Anotherissue that varnish in the carb can cause is that the varnish may not allow thefloat needle to seal properly against the seat, causing the flow of gas to notshut off when the bowl is full. The result will be gas overflowing the carb andrunning into the cylinder, and possibly out the air intake. If the gas getsinto the cylinder, it will seep past the rings and down into the crankcase.This will be evidenced by your oil level being over-full and/or the oilsmelling like gas.

Ifthis is the case, you will need to change the oil and filter, if it has a filter.

Varnishcan also cause the float needle to stick shut, and not allow any gas to flowfrom the carb bowl into the engine.

Theonly 2 solutions are to either replace the carburetor or give it a good,thorough cleaning.

Whenremoving the carb, make sure to take a good picture, or make a good drawing ofwhere all springs and linkages are attached. This will make reassembly mucheasier.

Mostpeople believe that cleaning a carb involves removing the bowl and wiping itout, then spraying some carb cleaner through it.

Thisis simply insufficient. It takes months or years for this accumulation to buildup – it just can not be removed in minutes.

Toproperly clean the carb, you must remove it, disassemble it (making sure toremove all non-metal parts), and soak it in a commercial solvent for severalhours. Soaking it overnight is even better.

Thenclean all solvent off with a spray type carb cleaner, making sure to get lotsof cleaner into every hole and passage there is. Pay special attention to thetiny holes in the bore of the carb, under the throttle plate for the carbs thathave these holes. Use lots of cleaner. And make sure to wear safety goggles toavoid getting the over spray into your eyes. There will be over spray.

Drythe carb with low pressure compressed air.

Whenreassembling the carb, make sure to use a carb kit, when one is available foryour carb.

Often,even a good cleaning is not going to be sufficient, and you may end up havingto replace the carb anyhow. Be prepared for this.

If for some odd reason this does not help, please let meknow so I can assist you further.


Expert:  Hank F. replied 1 year ago.

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