Dear Members;

I was wondering if perhaps you could give me some help. My mower a Lawnboy uses the Honda GCV 160cc engine on it. It also has the blade clutch engage and disengage.

The mower is used. It ran fine the first 1 or 2 times, then it started to idle rough and surge both at low and high speed. When the blade is engaged it runs fine. It also starts fine as well in choke mode. As soon as it is changed into fast speed after starting on choke is starts to surge. One can see the governor linkage hunting back and forth ( i.e. speeding up and slowing down cyclically). Same thing on low speed. I have read that this seems to be a common problem on Honda engines and solutions vary do not seem to point to one problem.

Items that I have checked--- Spark plug replaced

- Gas replaced

- Filter cleaned ( ran without filterÂdidnÂt help)

- Checked for plugged gas cap vent ( ran without gas cap, no change)

- Cleaned Carburetor twice

Remove the main jet and even the secondary jet behind the main jet ( clean with carb cleaner and thin wire) The cleaner looked to be exiting all the various ports after a good spraying all over. As a side note when I looked at the new spark plug after trying to run it in the above condition it was covered in black carbon. I cleaned it off.

Honda states to look for a plugged pilot screw , pilot jet clogged, pilot jet air clogged. Here is the link--- http://www.honda-engines-eu.com/en/images/59139.pdf

I cannot remove the pilot screw without taking off the limiter cap which will break the screw. But when I sprayed through the pilot jet air path carb spray came through the needle port. So I would not think that it would be clogged.

I decided to try to adjust the Throttle stop screw thinking that would assist the surging problem, but it did not help and made things worse. I think that in trying to adjust it I could not find the original position it was in after several attempts. Now on top of the rough idle/surging at low and fast speed, when I try to engage the blade the engine dies. I am assuming that it was my adjustment of the throttle stop screw that caused this or could it be coincidental? I am not sure.

I am at a loss as what to do. I need to know how to reset/adjust the throttle stop screw into its proper position so that the blade clutch can be engaged without stalling and secondly how to stop the surging at low and fast speed.

The only other options I can think of is that there is a leak causing a vacuum, which would warrant changing all the carb gaskets. Do you think that the carb could still be dirty or clogged? Governor out of adjustment ( not sure how I would tackle that problem) Valve clearance incorrect.

I appreciate any help that you could give me. Thank-you

Regards;

Stephen