QuestionQUESTION: I have a John Deere 265 with a 17HP Kawsaki FC540V engine in it. I have replace the carburetor, but it still throbs when in warms up. I runs fine till it warms up but than begans to throb. It throbs the worst with the throttle in the middle postition. This is the case when the valves are adjusted correctly to .006in. I can adjust the fuel valve down till it quits throbbing but then you have to chock it when every time you start it and it dies if pull the throttle from fast idle to slow idly to quickly.
ANSWER: Did you check all the gaskets and seals around the carburetor?
Is the Insulator Part Number: 16073-2097 warped and causing an air leak?
Did you perform a cylinder leak down test to make sure there are no leaks?
I once had a slightly loose head bolt cause surging...rare but the leak down tester clearly showed a leak.
I would use a file and check the insulator to make sure it is not warped.
Eric
---------- FOLLOW-UP ----------
QUESTION: Is a cylinder leak down test the same as a compression test? I performed a compression test and was good. I will try replacing the seals around the carburetor and the insulator(16073-2097) is broken so I will replace it.
Thanks so much for your help!
AnswerLeak down test uses compressed air, through the spark plug hole, to see how much air is leaking past the piston, rings and valves. Different than a compression test; more accurate to determine exactly which part is leaking.
If the insulator is broken I'm betting it is contributing to the problem.
Eric
