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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26744
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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We have one of these guys and it recently started surging at

Customer Question

Hi we have one of these guys and it recently started surging at idle all else is good whats gives?
JA: I'll do all I can to help. Tell me a bit more about what's going on so we can help you best.
Customer: like I said it surges at idle...starts good runs good-- surges at idle ...I assume that it tries to die from lack of fuel cause if you choke it somewhat the problem goes away
JA: Is there anything else the Small Engine Technician should be aware of?
Customer: no ............400 hrs
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Small Engine Technician about your situation and then connect you two.
Submitted: 9 months ago.
Category: Small Engine
Expert:  Curtis B. replied 9 months ago.

Make and model? Engine ?

Customer: replied 9 months ago.
Kawasaki 18 hp v twin FH531V BS06
Expert:  Curtis B. replied 9 months ago.

Have you ran a cylinder balance test? Loosen the spark plug wires, and with the engine idling, remove one wire at a time. Engine should continue to run. If engine dies when either wire is removed, the opposite cylinder is not firing. If both cylinders are firing, and only problem is the surging at idle, try taking the slack out of the springs on the throttle linkage at the carburetor. Do not add tension, but take out the slack. But I really think you will find engine is firing only on one cylinder!

Customer: replied 9 months ago.
I personally think the problem is a little dirt in the idle circuit because if you add just a little choke, the problem is gone. I know the sound of a miss and this motor runs very well other than at minimum idle. then it tries to stall and the govenor picks it up and then back and forth it goes (surges)
Expert:  Curtis B. replied 9 months ago.

OK, I just know how well these engine run on one cylinder, and when they do , they surge at idle. To clean the idle circuit, the carburetor will need to be removed and completely disassembled to clean effectively.

Customer: replied 9 months ago.
did your engine balance test and changed the plugs while I was there. nothing has changed still surging at idle only
Expert:  Curtis B. replied 9 months ago.

So I assume the cylinders were both firing, and engine did not die. Try a fuel test line , direct from the fuel pump inlet, into a separate fuel container and see if surge goes away.