StatesboroMike
Member
- Joined
- Aug 2, 2018
- Threads
- 6
- Messages
- 26
I have a Poulan Pro PP20VA46 lawn tractor that is about a year old. It has a B&S 20hp Intek V-Twin engine. Code is 40N877-0004G1-170627YG. It ran perfectly until a few months ago when someone broke into my shed and stole all my fuel, including draining the tanks of all of my gas-powered equipment (I have a suspect but no proof 
). It began surging badly after that. I took apart the carb and gave it a good cleaning. I also did the same for the fuel tank and lines. After that it ran smoothly until a few weeks ago when it began surging again. Once more I took apart the carb and cleaned it but the surging continued. After taking it apart and cleaning it a second time the governor gear exploded (my fault, I misadjusted it). I have since replaced the governor (and I made sure I found all the pieces of the exploded governor) and adjusted it according to the procedure outlined in a service manual another member here was kind enough to send to me. In fact, I have given it what amounts to a full service. Here is what I have done:
replaced fuel, air, and oil filters
cleaned mower deck and frame of debris
sharpened blades
leveled deck and adjusted gauge wheels
adjusted governor and throttle linkage per service manual
changed oil
cleaned fuel system (I use 89 Octane btw)
replaced spark plugs
installed new o rings in carb float bowl
replaced carb manifold gaskets
Cleaned the fuel pump
greased all lubrication points with lithium based marine grease (recommended by another member here)
aired all tires to proper psi
replaced choke return spring
After all this, I am STILL having issues! It starts fine and continues to run but only at full throttle and that roughly. Even then it seems to be operating at a much lower rpm than Fast mode implies. If I throttle down it starts to surge badly. It also surges and loses power when I engage the blades. Even without a load it runs sluggishly just driving it around.
So what could be the issue? I've heard of other people with similar engines having to replace the entire carb. Could this be it? Or could it have something to do with the valves? Or could it be something else entirely? This is my Hail Mary effort before taking it to a professional or taking my sledgehammer to it and buying a new engine. Any input will be greatly appreciated. PS: I did use a liquid gasket maker rather than purchasing a premade gasket for the engine. I'm sure I did a thorough job in sealing the engine case however. Should I crack it open again and replace it with a premade gasket?
). It began surging badly after that. I took apart the carb and gave it a good cleaning. I also did the same for the fuel tank and lines. After that it ran smoothly until a few weeks ago when it began surging again. Once more I took apart the carb and cleaned it but the surging continued. After taking it apart and cleaning it a second time the governor gear exploded (my fault, I misadjusted it). I have since replaced the governor (and I made sure I found all the pieces of the exploded governor) and adjusted it according to the procedure outlined in a service manual another member here was kind enough to send to me. In fact, I have given it what amounts to a full service. Here is what I have done:replaced fuel, air, and oil filters
cleaned mower deck and frame of debris
sharpened blades
leveled deck and adjusted gauge wheels
adjusted governor and throttle linkage per service manual
changed oil
cleaned fuel system (I use 89 Octane btw)
replaced spark plugs
installed new o rings in carb float bowl
replaced carb manifold gaskets
Cleaned the fuel pump
greased all lubrication points with lithium based marine grease (recommended by another member here)
aired all tires to proper psi
replaced choke return spring
After all this, I am STILL having issues! It starts fine and continues to run but only at full throttle and that roughly. Even then it seems to be operating at a much lower rpm than Fast mode implies. If I throttle down it starts to surge badly. It also surges and loses power when I engage the blades. Even without a load it runs sluggishly just driving it around.
So what could be the issue? I've heard of other people with similar engines having to replace the entire carb. Could this be it? Or could it have something to do with the valves? Or could it be something else entirely? This is my Hail Mary effort before taking it to a professional or taking my sledgehammer to it and buying a new engine. Any input will be greatly appreciated. PS: I did use a liquid gasket maker rather than purchasing a premade gasket for the engine. I'm sure I did a thorough job in sealing the engine case however. Should I crack it open again and replace it with a premade gasket?
Last edited:
