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Engine Silver Series LB wont stay running.
- Thread starter tlwright21
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A violent stopping of mower/With a new crank, if you can find one. I would say if you cannot cure issue with carb adjustments your only process of elimination is the crank imho. You can spray carb cleaner or ether/starting fluid under mower while it running to see if you have a damaged seal, there should be no RPM change. If RPM jumps then you have a seal bad. Ebay you can probably find a motor. I have not seen a short block for the 4.75 hp LB.
I had the same mower for probably as long as you did. My son filled with gas when I was out of town, did not know I filled with fresh gas but normally had mixed in can. I bought a duraforce in replacement. You can find them on craiglist readily and you can also get short blocks for around a 100.00 which is crank and cylinder assembly. That is what I did, bought a donor mower for 25.00 and put a new short block in.
i shot with it starting fluid to keep it running and it did not raise the engine rpm. I'm going to buy a new air vane spring. the air vane was going to the closed position while it was briefly running. i haven't ever touched it, didn't not ever even know what the air vane was or what it did
i shot with it starting fluid to keep it running and it did not raise the engine rpm. I'm going to buy a new air vane spring. the air vane was going to the closed position while it was briefly running. i haven't ever touched it, didn't not ever even know what the air vane was or what it did
You have to spray underneath or in the deck as mower is running not into the carb intake. X2 on key, have to pull the tank, cover and recoil to see top of flywheel.
tlwright21
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The vane is a governor, the more load on engine the more it opens up throttle. Your spring is probably sacked out or something is binding which is why no difference in throttle change rpm. To replace the spring you have to remove the throttle plate/butterfly (looks like a penny) Just use a needle nose and pull it, The spring has a tab the sits in the dial adjuster and the other end goes into throttle. To set it clockwise each click is 25 rpm at full throttle, want 3000 to 3200 rpm. I have done in the past is tie up the safety handle and start mower, you can turn the vane by hand to run throttle up and down. You should be able to do this to see if you can get it to stay running.
i started it up with primer/ starting fluid. the air vane was in the closed position while running and trying to die. I manually opened it with my hand while pumping the primer. i managed to keep it running for a minute or so before it died. the motor was running at full rpm and except for the fact it was running out of fuel it was running stong as it always has.
soooo do I spend a $100 and buy a brand new carb. by all appearance there is nothing wrong with this one other than the engine won't run for no known reason.
They are simple carbs, as long as the float is set right and the needle is working correctly so the carb is not flooding (leaking gas when not running) or preventing enough gas into bowl, it should run. The throttle plate can wear into plastic (should be very little play in throttle plate) causing it to stick. Does the vane move back and forth with out sticking? You can warp the front of the carb where it attaches to the motor intake, you should be able to make your own gasket if that is the case. The jets main and idle could be plugged, but they are easy to clean and should last for several years.
Before buying a new carb or finding one on ebay I would inspect the flywheel key. If you manually open the throttle and it still did not rev up something has to be up with the motor. Could also be damaged reeds. They are in the case behind the carb. They should be tight against the opening no gap.
Before buying a new carb or finding one on ebay I would inspect the flywheel key. If you manually open the throttle and it still did not rev up something has to be up with the motor. Could also be damaged reeds. They are in the case behind the carb. They should be tight against the opening no gap.
tlwright21
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They are simple carbs, as long as the float is set right and the needle is working correctly so the carb is not flooding (leaking gas when not running) or preventing enough gas into bowl, it should run. The throttle plate can wear into plastic (should be very little play in throttle plate) causing it to stick. Does the vane move back and forth with out sticking? You can warp the front of the carb where it attaches to the motor intake, you should be able to make your own gasket if that is the case. The jets main and idle could be plugged, but they are easy to clean and should last for several years.
Before buying a new carb or finding one on ebay I would inspect the flywheel key. If you manually open the throttle and it still did not rev up something has to be up with the motor. Could also be damaged reeds. They are in the case behind the carb. They should be tight against the opening no gap.
call me a LB mechanic. I removed the strainer screen inside the carb. doesn't appear plugged but wanted to remove the possibility it was choking the jet. Also cranked in about 6 clicks on the governor collar and the motor fired and ran and sat there running. Yahooo. I'm going to buy a new screen for the heck of it. Really believe that the spring is weak and couldn't hold itself open against the flywheel wind. so i think it is fixed. just needed more spring pressure applied on the air vane. guess I could buy another spring also and change it out.
call me a LB mechanic. I removed the strainer screen inside the carb. doesn't appear plugged but wanted to remove the possibility it was choking the jet. Also cranked in about 6 clicks on the governor collar and the motor fired and ran and sat there running. Yahooo. I'm going to buy a new screen for the heck of it. Really believe that the spring is weak and couldn't hold itself open against the flywheel wind. so i think it is fixed. just needed more spring pressure applied on the air vane. guess I could buy another spring also and change it out.
The springs are cheap and might be able to find one locally at a toro/LB dealer. The tab can work itself out of the notch thus loosing tension, I know when you replace the spring you have to be careful so it stays in place.