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B&S 16HP Losing Power


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04-20-10, 06:13 AM   #1  
B&S 16HP Losing Power

Hello All,

I have a Briggs & Stratton 16 HP Vanguard V-Twin (303447-0030-01) on a Simplicity Front-Cut Wheel Steer lawn mower. The last couple of summers it seems to be losing engine power. Especially in heavy grass with new and/or sharpened blades. Once it hits heavy grass is cuts out and sputters black smoke. Otherwise it runs great.
Any ideas? Do I need news valves, rings and gaskets? Is there a good place to buy a rebuild kit for these engines at a reasonable price?

HELP!!! New engine costs big $$$.

Thanks,
Simplistic_1

 
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indypower1's Avatar
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04-20-10, 07:44 AM   #2  
Sounds like the valves need to be adjusted.

 
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04-20-10, 09:20 AM   #3  
Sounds to me like the choke is sticking on.


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

God bless!

 
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04-20-10, 10:57 AM   #4  
Cheese & indypower1

Thank you both for the responses.

A What is the proper method for adjusting the valves
B would a carbuerator kit take care of the sticking choke issue?

Simplistic_1

 
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04-20-10, 11:48 AM   #5  
answer to question "b". No a carb kit will not do anything about the choke. You are going to have to check to see if it is sticking and if so find out why. Most likely just need to spray penetrating oil on the shaft and work the choke back & forth.

answer to question "a". Here is a video adjusting the valves.

YouTube - Lawn Mower Repair Valve Adjustment V-Twin

 
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04-21-10, 07:12 AM   #6  
indypower1,

once again thank you for the information. Last night as I was working on the darn thing I found I'm no longer getting spark to the spark plug. Just another bump in the road but after spending three hours tracing wires for a possible short and a six-pack I have not been able to pinpoint the cause.

Once I get the darn thing to fire I will let you all know the outcome of the valve and choke suggestions. It's good to post whether or not the suggestions given actually resolve the issue so others can benefit as well.

Thanks again,
Simplistic_1

 
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04-21-10, 08:54 AM   #7  
Have you installed new spark plugs?

 
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04-21-10, 10:11 AM   #8  
16 HP B&S Spark

If you had spark before check to be sure all your safety switches are engaged. IE. seat safety ,netrual and clutch. I just went through this on a John Deere I was rebuilding and after several hours discovered I did not have it in netrual.
Backachers

 
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04-21-10, 10:13 AM   #9  
I did install a brand new spark plug over the weekend. Unfortunately that didn't help. It fired up last year before storing it for the winter so I'm a bit puzzled.

Once I get the spark issue figured out I'll let you know how the choke and valve suggestions work so that other forum users can benefit.

Backachers, as I was going through the wiring I was checking for disconnected wires or loose connections. I will now check each connection to make sure proper contact is being made.

Thanks,
Simplistic_1


Last edited by simplistic_1; 04-21-10 at 12:51 PM.
 
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04-21-10, 05:39 PM   #10  
Are you grounding the plug when checking for spark?

Does it have spark with the kill wire disconnected from the coil?


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04-22-10, 08:02 AM   #11  
Cheese,

I am grounding the plug to a clean solid metal state (not aluminum or rusty metal etc..).

Which wire is the kill wire?

Thanks,
Simplisctic_1

 
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04-22-10, 08:09 AM   #12  
indypower1,

I pulled the valve cover off of the right side first. I was amazed at what I found. Both push rods were laying loose in the case. Not sure how long it had been like this. They were not bent, dinged scratched or anything I'm not sure if they were just that loose that i knocked them around when I pulled the valve cover off. Either wayI reconnected them and adjusted the valves to .004.
I then pulled the valve cover from the left side and they were in tact but loose. I adjusted them to .004 as well. By this time it was around 11:30 PM so I hung it up for the night.

The choke did not appear to be sticking at all. It moves freely, opens, closes without any stickyness.

I'll keep you posted.

Thanks again,
Simplistic_1

 
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04-22-10, 12:06 PM   #13  
Posted By: simplistic_1 indypower1,

I pulled the valve cover off of the right side first. I was amazed at what I found. Both push rods were laying loose in the case. Not sure how long it had been like this. They were not bent, dinged scratched or anything I'm not sure if they were just that loose that i knocked them around when I pulled the valve cover off. Either wayI reconnected them and adjusted the valves to .004.
I then pulled the valve cover from the left side and they were in tact but loose. I adjusted them to .004 as well. By this time it was around 11:30 PM so I hung it up for the night.

The choke did not appear to be sticking at all. It moves freely, opens, closes without any stickyness.

I'll keep you posted.

Thanks again,
Simplistic_1
Sounds like you maybe getting close. How did the valves look?.. Did you notice any gunky buildup?.. If so, make sure to clean those areas as well..

 
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04-22-10, 12:45 PM   #14  
jnt412,

The valves were remarkably clean. I was actually surprised at how clean everything looked. Although I change the oil every spring I was really expecting some build-up. Amen to synthetic oil I guess.


Thanks,
Simplistic_1

 
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04-23-10, 01:07 AM   #15  
The kill wire connects to the bottom of the coils. It has a diode inline that can cause it to lose spark when it blows.


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04-23-10, 09:21 PM   #16  
OK - I now have spark, after pulling the flywheel cover and cleaning both the magnetos and the flywheel of rust. However, most times when I turn the key to start the mower nothing happens...i hear a subtle click indicating something receives power (starter solenoid?). Once in a while after turning the key numerous times it will fire up......BUT.....I am not able to turn it off. I just put a new key switch on early last year. Grrrrrr....frustration....but yet so close!!

Thanks,
Simplistic_1

 
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04-25-10, 01:13 PM   #17  
1. Did you put the kill wire back on the coil after you disconnected it to check for spark?
2. The problem engaging the starter sounds like the solenoid. Turn the key on and jump the two posts on the solenoid. If that starts it replace the solenoid. Easy fix once you get to the solenoid which will be buried somewhere. Follow the clicking sound. Good luck.

 
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