# Honda engine hunting [surges]



## TownWrench

*engine gx390 13.0 hp qaa2 gcaet 1092845. Engine is mounted on a pressure washer and surges when not pulling trigger to use water,when power washing, engine maintaines rpm without surging. If this isn't normal does anyone know how to adj.carb?*


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## 30yearTech

A restricted idle circuit will cause surging at all speeds when the engine is run under a no load condition. 

When the engine has no load, the throttle plate is barely cracked open and most of the fuel is metered through the idle circuit. When you have a restriction, the engine leans out and starts to die, then the governor opens the throttle to compensate for the drop in engine speed. When this happens enough fuel is fed through the main jet and the engine picks up speed once again, then the governor closes the throttle and the idle circuit takes back over. Then the whole process starts over again and you have a continuing surging of the engine. 

If the surging pretty much disappears at higher speeds with a load applied (such as blades engaged on a riding mower) then the idle circuit is the most likely cause.

On newer engines, there is no adjustment and the idle or low speed circuit just needs to be cleaned. It does not take much to restrict this circuit as the passage ways are very small, and the blockage may not even be visible.

Best of Luck....:thumbsup:


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