Surging--engine or govenor or fuel pump?

[handirifle]

I have the murray in the thread" Murray engine troubles" and have it running..again and for now. It seems it is constantly" hunting" as i mow. This happened once before and i trouble shot it to the fuel pump but now i am not sure. This engine is on its very last leg so i am not investing much. $ $ into it aany more.

It seems everytime i turn it off now it pops about 1 second after the engine stops. Kinda weird.

Can a backfire cause problems with these vacuum fuel pumps?

How can i troubleshoot the govenor? If it is the govenor can i bypass it? Like i said this motor is on its last leg and if i can get one or two more mows out of it i am happy.

 

[mostly_gas]

The only time I had a surging problem it was the fuel pump. I cleaned the sintered brass area on the back of the fuel pump and the surging quit.

 

[Tig]

Dirty carb caused that symptom on my Murray. It's one of the reasons the original owner dumped it. Fuel pump also sounds logical.
The pop is a running rich thing (I think). You made me laugh with that one. I used to drive the Murray into the my tin roofed shed, shut it down and then sit there with my hearing protection on until the bang was over. It was amazing how long the delay was sometimes. First time it did it, I was off the rider, hearing protection in hand and headed for the door. BANG! :confused2:
For the cheapie fix attempt I'd suggest opening the carb (4 screws on top) blow/wipe out the bowl and blow out any passages with compressed air. Feed it good dose of carb cleaner in the next tank.

 

[Wolfy]

I had a surging problem on my Simplicity. It was the governor. If you look where the spring hooks on, there should be several holes. I would move the spring to different holes, it did wonders for mine.