New IN Member with Engine Surging Issue

Hoff64 · Sep 11, 2019

I ran across this forum because I have a yard tractor issue I have been trying to solve. I have always enjoyed solving issues myself and with help of others who have been down a path ahead of me.

I have an 8 year old John Deere LA 135 that just started surging.
So far I have:
- Changed the fuel
- Changed the fuel pump
- Changed the fuel filter
- Cleaned the air filter
- Changed the spark plugs
- Changed the fuel tank cap
- Added Sea Foam to the fuel
The surging has continued, under the load of engaging the blades, but after about 30 to 45 minutes of mowing like that, the engine kicks over and runs like it was new, without surging. I have had this happen twice now.

What happens to cause this shift/reversion to a purring engine after 30 to 45 minutes?
And is it harmful to my engine to mow with it surging for 30 to 45 minutes?

Thanks for any input, Hoff64

TBN Support · Sep 11, 2019

:welcome:

Welcome to the forum!

I'm going to move this thread over to our John Deere section.

Hoff64 · Sep 11, 2019

Thanks Catherine.

Richard001 · Sep 11, 2019

Time to clean the carb.

What do the spark plugs look like? Is it running lean ?

And welcome to TBN

Richard

oldnslo · Sep 11, 2019

I have had three different JD models with Kawasaki engines that replacing the float needle in the carb solved random surging problems. I suspect that the needle gets some wear and then occasionally sticks or binds preventing full flow of gas into the carb.

Not sure if this could be the same issue on a LA model or not?

tomplum · Sep 12, 2019

Typically carb or debris in the carb related. Could be a worn float valve. O ring at the bottom fuel pick up as well. If the carb solenoid is screwed to the side of the bowl, you can remove it to drain out what may in the bowl. Though debris may be in the fuel pick up itself. There is a bit going on with these carbs. If you are not familiar with then, it may be best to order a new OEM Briggs carb and replace it.