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20HP B&S mower problems!


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07-31-14, 08:46 PM   #1  
20HP B&S mower problems!

Hi Everyone -- Newbie here, but willing to learn. I'm having trouble starting my B&S riding mower. It's an older "Lawn General" with a 20 hp B&S twin II engine, model 460777, type 2277 E1. I bought it used 2 years ago. I think there are a few issues going on here, so I'll walk through all the things that I'm worried about.

The problem now is that I can't start it -- I can't spin the flywheel fast enough. I get a small bit of movement, and then rapid clicking sounds.

I was definitely running on low oil (I know, I know -- I didn't check it before taking it out -- lesson learned), mower worked fine for about 45 minutes, and then when I idled down for a second, it stalled and wouldn't start up again. This actually always happens (i.e., won't start immediately after I shut it off), so I just push it back to the garage and wait for it to cool off before trying to start it. This time, however, it only clicked the next day -- not even close to starting. I tried to spin the flywheel by hand and it wouldn't budge. Sprayed some PBblaster thru the spark plug holes, and let it sit for 2 days. Then, got a wrench around the flywheel nut, and it eventually started to turn. Now it turns by hand (but not sure if there's more resistance than there should be). Also, it seems to be about the same amount of resistance regardless of whether or not there's a sparkplug in or not. It'll turn with one hand, whereas before I just couldn't move it at all. No weird metal sounds or anything. Don't know what I'm doing, but took off the heads, and can see the pistons and valves moving, and no bits of metal. I've changed the oil -- it was pretty black, but didn't see any metal flakes or anything.

So, at one point, after letting the mower sit with the PBblaster for a bit, I tried the ignition and it spun the flywheel pretty fast. So, I thought it was fixed, and waited for the morning to try firing it up with the sparkplugs inserted. No luck. It just wouldn't spin so much any more. Even without the sparkplugs, it still doesn't spin -- less than a full revolution. A few times, the gear on the starter woudln't engage the flywheel (stays low), and it can spin, but even then, if I hold the ignition, it kinda dies out/fades out over a few seconds. Not sure if it's supposed to behave like this. I've cleaned the battery terminals, and tried jumping with a car battery.

One other thing - this last time I was using it, I accidentally went over a pretty large branch of a tree that was buried under tall grass -- it didn't stop the mower, and from what I read, sounds like a sheared flywheel key wouldn't cause the symptoms I have, but I want to give you all the info regardless.

My best guess here is that it needs a new starter, but I also wonder whether it could be something else given the seizing and oil issue. I'd hate it junk it over a starter, but also don't want to just throw parts at this thing if you all think it's toast. So, obviously any advice you have would be much appreciated.

I think I've covered everything, but let me know if I'm leaving something out.

Thanks!!

 
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07-31-14, 10:58 PM   #2  
The clicking sound is low voltage at the solenoid. The battery is low and you must not have had a good connection with the jumper cables when you tried to jump it.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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08-01-14, 04:20 AM   #3  
Thanks Cheese -- Ok, I'll try jumping again.. But, pretty sure I did have a good connection. Will update once I test again.

 
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08-01-14, 07:38 AM   #4  
Hi Cheese -- So, I just had the chance to try jumping again, and as far as I can tell, it's gripped on there well. This time, without one of the plugs in, it did turn okay (I think -- don't know how fast it normally should go, but seemed to move relatively freely and smoothly). So, I put the plug back in, it spun, and sputtered once or twice like it wanted to start. No luck on starting it though. Then, tried the ignition again, and could see the flywheel trying to turn, but now it doesn't continue to spin. It does one turn (I think it's a complete turn), pauses slightly, turns again. Then a longer pause; then repeats. Tried doing this a bunch of times, always with the same result. is this normal, corresponding to the piston movement/compression?

I next tried turning on my car that I was using to jump it. This time, it again spun continuously, but again didn't start up. So, I tried the motor ignition again, and then it was back to those weird partial turns again.

When I disconnected the jumper cables, I tried once again just with the mower battery, and basically hear a weak click coming from the solenoid and the gear on the starter didn't even turn. The rapid clicking I hear from the starter fades pretty quickly (i.e., it noticeably gets quieter within a sceond or two). I opened up the compartment where the solenoid is located, and found a ton of grass in there. So, I cleaned out a bit, but no improvement.

Any thoughts now? Is it possible I somehow damaged the engine running with low, dirty oil, making it harder than normal to turn over? Or, is it possible the starter is weak/damaged?

Thanks again!

 
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08-01-14, 08:04 PM   #5  
I think you need to adjust the valves to get it to crank easily again, and you have a bad or low battery on top of it, compounding the issue. The rapid clicking noise that went away after jumping it confirms the battery problem.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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08-02-14, 05:47 AM   #6  
How would I adjust the valves on this type of engine? Is that a very involved process? Also, how do we know it's not a weak starter?

 
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08-03-14, 05:35 AM   #7  
Well, you were right about the battery. I put a trickle charger on it, and afterwards it fired right up. So, I guess I didn't have a good bite on it when jumping. Its decently loud. Do you think valve adjustment is still necessary and will help? Also, the engine seems very hot after running it for a few minutes. Not sure how hot it should get and whether it's within normal specs, but if you have ideas of what I could look at, let me know.

 
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08-03-14, 06:10 AM   #8  
That dirty oil will not help it to run cool . . . . just the opposite.

 
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08-03-14, 07:01 AM   #9  
I've already changed the oil. Nice and clean.

 
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08-03-14, 06:46 PM   #10  
They can get fairly hot, not sure how hot yours is getting. It wouldn't hurt to adjust the valves, since it sounds like it has probably never been done before and it is recommended routine maintenance.


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08-03-14, 07:03 PM   #11  
So, I just used it to mow my grass, and after about 30 minutes, it started making lots of noise and stalling. Started back up a few times, but now I can't start it, and I hear metal rattling around in there when I try.. That can't be good.

Any thoughts? I think this might be the end of itů

 
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08-03-14, 07:48 PM   #12  
Yep. It's gone south. Battery may still be good, though.

 
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