Small Engines (Lawn Mowers, etc.)/John Deere RX75 Carb


QUESTION: I have a pulsating carb on my RX75. I took it apart and cleaned it and it still is pulsating. How do I adjust the carb?

ANSWER: Do you have a Kawasaki engine?


---------- FOLLOW-UP ----------

QUESTION: Yes it does, it is a Kawasaki 9HP Over Head Valve
Code: FC290V-BS10
E/NO; FC290V158945

ANSWER: You can download the service manual at the URL below:

This link may be helpful as well:

As far as adjusting, most manuals state to start the adjustment from a GENTLY seated position (just very lightly seated, finger SNUG) and then turn out 1 1/4 to 1 1/2 turns out for initial setting.  

You should note this is only for older engines/carbs.  Today's carbs, if adjustable, have various settings.  I always count how many turns when removing to get a rough idea of the setting when dis-assembling for cleaning.

My be there is still something in the carb.  Have you checked the valve clearances recently?


---------- FOLLOW-UP ----------

QUESTION: No I have not could that make the engine rev up and down erratically like that or pulsate.

Valves rarely causing the puslating, hunting, or surging problem you described but the OHV's are pretty easy to check the clearances.

The problem you described (pulsating) is almost always a dirty carb issue.  Don't forget to drain and blow compressed air through the fuel tank and fuel lines as well to make sure there is not any dirt/debris in them.  Check you fuel cans as well and make sure they are clean.

I have had to clean some Kawasaki carbs a couple of times to get the pulsating to stop...the carb can be very sensitive but work great when they are working.  I have an older model similar to yours, just smaller, and it is a very effecient engine using very little fuel and has sufficeint the quiet ans smooth operation.

Did you download the engine service manual?
Let me know how the carb cleaning goes.

Small Engines (Lawn Mowers, etc.)

All Answers

Answers by Expert:

Ask Experts


Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

©2017 All rights reserved.