Riding Mower Lack of Power

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  #1  
Old 06-03-18, 12:03 PM
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Riding Mower Lack of Power

I have a Simplicity Regent (2690437) riding lawnmower with a 20hp briggs intek v-twin engine. It is currently displaying a lack of power and the engine does not sound like it is running smoothly. In regards to the power, pressing on the accelerator pedal results in the mower moving forward more slowly than it used to. I'm not an expert in engine noises, but the engine is perhaps making a bit of a pinging or misfiring noise.

So far this season, I have changed the oil, changed the spark plugs, and replaced a worn drive belt. However, none of these seemed to make a difference on the lack of power. I did also confirm that both plugs are sparking, although i am not a great judge of how strong the spark is.
 
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  #2  
Old 06-03-18, 02:32 PM
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Are both cylinders firing?

When you replaced the spark plugs what did the old ones look like?
 
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Old 06-03-18, 03:12 PM
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How do I know if both cylinders are firing?

The ends of both plugs were black and at least one of them looked to have some oil on it. I did decide to check the oil level at that time, and it was within the ideal zone.
 
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Old 06-03-18, 03:19 PM
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Make sure your choke is operating correctly.
 
  #5  
Old 06-03-18, 04:49 PM
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In terms of the choke, I can confirm that opening and closing it does make a difference in engine operation, as I do have to adjust it every time that I do a cold start on the mower. Am I correct in assuming that this would be a good indicator that it is working properly?
 
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Old 06-03-18, 05:43 PM
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Is the exhaust smoking? If so and with the oil covered spark plug I would put a blown head gasket on the list of potential causes.
 
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Old 06-03-18, 06:03 PM
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I think it does smoke a bit when I first start the mower but not after that.
 
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Old 06-04-18, 05:08 AM
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Check for spark at both cylinders and if both have spark I would look for others signs you might have a blown head gasket. If that's it it's a pretty inexpensive repair.
 
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Old 06-04-18, 08:14 AM
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I don't see where it was ever confirmed the engine was running on both cylinders, start it and remove one spark plug wire if the engine tempo changes/starts to miss then that cylinder is firing then try it on the other cylinder. Have a good one. Geo
 
  #10  
Old 06-04-18, 03:27 PM
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Thanks for the detailed instructions. I have now confirmed that the engine is running on both cylinders.
 
  #11  
Old 06-05-18, 06:34 PM
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Is there something that I should check with the head gasket next? I will say that I am not noticing a constant smoking like I saw in several videos that demonstrated symptoms of a failed head gasket.
 
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Old 06-06-18, 05:23 AM
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Do some reading online. There are many different symptoms. Smoke, fowling spark plugs, oil on spark plugs, more than usual amount of oil blown up into air filter housing.

I don't recall you mentioning changing the air filter. Have you done that? A clogged air filter can rob power.
 
  #13  
Old 06-08-18, 05:23 AM
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The air filter looks a little dusty, but not too bad by my eye. I fired up the mower, let it run for a minute, and then removed the air filter. It made no difference in terms of how the engine runs.
 
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Old 06-10-18, 09:55 AM
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Someone that I know recommended doing a compression test. I did that earlier today and found that the left cylinder (as I sit in the driver seat) has 140psi. The right cylinder has 130psi. Does that sound reasonable for this type of engine? I don't think I previously mentioned this, so the engine number is 406577.
 
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Old 06-10-18, 01:28 PM
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Those numbers are great. What color is the smoke? Have you checked the valves and their adjustments?
 
  #16  
Old 06-12-18, 04:15 PM
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I double-checked again to be certain on the smoke item. When I first start the mower, there is a decently strong exhaust smell, but no smoke at this point. Perhaps this is pretty normal.

I have not looked at the valves. Do you have a recommended video or instructions for that?
 
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Old 06-13-18, 12:16 AM
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I'd start by removing the valve covers and making sure the push rods and rocker arms are in palce and not loose.
 
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Old 06-15-18, 07:08 PM
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This is another demonstration of my ignorance on this topic, but after investigating further, it turns out that the noise that I was hearing and thought was coming from the engine is actually coming from the transmission area. After doing some further research, I am looking into changing the transmission oil.

In addition, I have noticed that there is another belt that has the beginning of a tear in it. I'm planning on replacing it. The part number is 1728008 with a description of "V-BELT, Drive Belt, Aramid/Kevlar". I don't know if this is normal, but I also notice that it is quite loose.

Obviously, the noise from the transmission doesn't explain the oil that I saw on my spark plug earlier, but perhaps it is the source of the mower's reduced power.
 
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Old 06-15-18, 07:27 PM
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You folks probably already know this, but maybe it will be helpful for someone else to read. The belt is the transmission drive belt. It appears that this is loose when the parking brake is on, but then tightens up when you release the parking brake.
 
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Old 06-15-18, 11:28 PM
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When you say reduced power, that indicates the engine is not running properly. Is it the engine not running properly, or is the mower not going as fast as it was? The transmission belt could cause noise and loss of speed and pulling ability but not a loss of engine power. Just trying to clarify if it's an engine problem or not.
 
  #21  
Old 06-16-18, 09:52 AM
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The mower is not going as fast as it was.

Does anyone happen to know how to use a drill to purge a k46 transmission? I see some mentions of doing this on the input shaft, but have not seen any clear illustrations or videos showing where to find the input shaft.
 
  #22  
Old 06-16-18, 11:08 AM
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K46 means nothing to me?????????????
If it is a Hydro tranny the input shaft is the pulley that is driven by the drive belt. As for purging, lift and support the mower so the rear wheels are off the ground, pull the bypass lever that allows you to push the mower, then with the engine running engage the drive forward for 5 seconds, then reverse for 5 seconds. Repeat this 6 times. Now engage the bypass and repeat the above procedure.
 
  #23  
Old 06-18-18, 06:16 PM
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Thanks for your feedback. I did change the transmission oil, although nothing really changed. I have the transmission drive belt on order, so I'm going to try that next.
 
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