Reduced rpm on Briggs Stratton 450E Mower

[Spacecrow]

Hello all. Some of you remember my posts on the Weedeater push mower that kept cutting off. and now the latest.
I have been getting good results running ethanol blend fuel and running the mower dry. Today I started the mower and when it ran into a shallow depression it stalled out. Since then the engine runs at less than half the rpm it did before I hit the depression which I have ran over many times. I kept running the mower until the gas went dry. Periodically it stalls out but starts up again with out much trouble. I wonder if I broke a timing gear but the incident was not that hard on the mower. Another possibility is I put some carb cleaner and another additive in and I put too much in and hoping I burned up all that. I will fill the tank partially tomorrow and check the plug for fouling. I started the mower with the air cleaner off and not much difference also checked the oil. The underside was checked and no wires wrapped around the shaft or overheating. Thank you for any replys.

To sum up the engine ran at full rpm before cutting off and since then runs less than half the rpm but runs fairly smooth.

 

[Oddjob]

I suspect that you have slightly dislodged the flywheel and now your ignition timing is slightly off. Pull the flywheel and see if the woodruff key is still aligned in the slot in the crankshaft.

 

[sgkent]

without more information it is hard to answer. Maybe others might know what engine you have but my guess is most would not. Is it one cylinder, two cylinder, overhead valve, L-head. How does the throttle work, is it one speed fits all or a variable throttle? Four stroke or two stroke? Belt driven or direct shaft? Did you burn the additives off and add new fuel? A model and serial number could help answer those questions. It may be as simple as it is starving for fuel if you dislodged something that is partially plugging the fuel line.

 

[Spacecrow]

without more information it is hard to answer. Maybe others might know what engine you have but my guess is most would not. Is it one cylinder, two cylinder, overhead valve, L-head. How does the throttle work, is it one speed fits all or a variable throttle? Four stroke or two stroke? Belt driven or direct shaft? Did you burn the additives off and add new fuel? A model and serial number could help answer those questions. It may be as simple as it is starving for fuel if you dislodged something that is partially plugging the fuel line.

thank you for your reply. It's a briggs and stration 80000 450e very basic push mower model number 08p502-0064-f1. Today I plan to examine the spark plug for fouling and maybe replace it anyway. The additives were burned off I will try new fuel. I will report back the results. Oil level checks out fine.

 

[Spacecrow]

I suspect that you have slightly dislodged the flywheel and now your ignition timing is slightly off. Pull the flywheel and see if the woodruff key is still aligned in the slot in the crankshaft.

certainly sounds possible. I will get some easier checks out of the way and see if I can pull off that flywheel. I did source a woodruff key (it is actually a rectangle.)

 

[Rivets]

Don’t go after the flywheel key until you check the easier external parts. I suspect the governor setup has changed, reducing rpm speed. Please post a couple of pics of the carb a governor linkage.

 

[Spacecrow]

Don’t go after the flywheel key until you check the easier external parts. I suspect the governor setup has changed, reducing rpm speed. Please post a couple of pics of the carb a governor linkage.

the linkage at the carburator. old photo I will pull the cover off and see if something is blocking the device.

 

[Spacecrow]

Don’t go after the flywheel key until you check the easier external parts. I suspect the governor setup has changed, reducing rpm speed. Please post a couple of pics of the carb a governor linkage.

Holy smokes! You are right! The spring had come loose. All I had to do was reattach the spring and full power again! Thank you thank you thank you. https://i.ebayimg.com/images/g/5AEAAeSwr9dp5sI0/s-l1600.webp

 

[Rivets]

That’s why I always say start with the simple things first. A couple of years experience have taught me to that. A no charge fix instead of an $$$$ inexperienced tech looking in the wrong direction. Glad you found the solution.

 

[Spacecrow]