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Muffler on Briggs & Stratton 5HP engine gets red hot


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09-20-16, 04:52 PM   #1  
Muffler on Briggs & Stratton 5HP engine gets red hot

I was given a 1973 Montgomery Ward leaf vacuum that did not run. After cleaning out the gas tank, carburetor and carbon on the pistons I finally got it running. But the muffler gets red hot. I read that it could be running to lean and when I adjust that it runs bad and the muffler still gets red hot. Any ideas what the problem is? It has a 5HP B&S Engine.

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09-20-16, 06:31 PM   #2  
Post the engine model, type etc, usually stamped in the metal engine shroud just above the spark plug it will appear as xxxxx-xxxx-xx. Have a good one. Geo

 
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09-20-16, 07:17 PM   #3  
It's a Briggs & Stratton 5hp from 1973
130202 0209-02 6906257.

 
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09-20-16, 08:08 PM   #4  
Typically it's either a lean fuel/air mixture or pre-ignition from spark advance. Either drives up the combustion temperature.

 
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09-20-16, 10:34 PM   #5  
Is it glowing red so much that you see it in the daytime, or is this in the dark? These old engines sometimes have such minimal mufflers that were small and restrictive and got very hot. Red hot, but not not so hot that it's cherry in the daylight. Late timing or lean mixture can cause it too. If it has points, I'd reset them or really I'd put a new coil on it and just forget the points (the new coils come with electronic ignition).


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09-21-16, 03:01 AM   #6  
It's bright red in the day time. Adjusting the carburetor does not help and just makes it run bad. when I shut it down sometimes fire shoots out of the muffler.

 
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09-21-16, 03:48 AM   #7  
If you're actually getting a richer mixture, it will cool the exhaust. Can you get black smoke from the exhaust by setting the mixture screw? The screw would normally be turned counter clockwise.
You may have an obstruction in the main jet circuit that cleaning missed.

 
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09-21-16, 04:15 AM   #8  
With all of the cleaning that was done, did you check the muffler itself for obstructions ?

Being on a 1973 unit, I don't suppose that it's the original muffler, and some have internal screens and baffles that can rust and fall apart over time and become obstructions to smooth air flow.

 
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09-21-16, 07:05 AM   #9  
I cant get black smoke and when I back off on the screw it runs bad.

I'll check the muffler but i dont think there is much to check. Will running the engine without the muffler tell me anything? With the muffler on the exhaust is so hot I'm sure it could start a fire. If i take it off and its not as hot maybe that would tell me the problem is the muffler. I'll check that out when i get home.

I dont know much about this stuff and i was thrilled that I got my uncles old machine running. I knew it was too good to be true. But i wont give up.

 
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09-21-16, 09:25 AM   #10  
I would suggest a couple things, while it is idling spray some carb/brake parts cleaner behind the carb if the engine tempo changes you have an air leak creating the lean condition also check the flywheel key for damage which would cause the timing issue. Have a good one. Geo

 
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09-21-16, 11:10 AM   #11  
The other thing you can do is use octane booster in the gas. That will slow the burn down.

 
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09-21-16, 04:32 PM   #12  
Flywheel key, Points/condenser, or too much RPM. It's one or more of these.


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09-22-16, 06:50 PM   #13  
take a look at the flywheel key in the photo. Does that look like it is ok or do i need to pull the flywheel? I also show a couple pictures of the hot muffler. It get white hot inside.Name:  ccc.jpg
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i'm not sure if i uploaded them correctly

 
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09-23-16, 07:36 AM   #14  
The key/keyway is fine. You'll need to look at the points/point gap, etc. to see where the timing is, though.

The problem you have is the muffler is getting too hot when it's that close to the gas tank. That is too dangerous to ignore.

Run it for a short time, then shut it off by popping the spark plug wire off, so it'll stop suddenly. Take a picture of the spark plug electrode end and post it.

 
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09-23-16, 08:11 AM   #15  
Posted By: marbobj ". . . The problem you have is the muffler is getting too hot when it's that close to the gas tank. That is too dangerous to ignore . . ."
I was thinking the same thing, and wondered whether that is even the correct muffler for that unit, configured as it is ?

 
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09-23-16, 08:18 AM   #16  
If that is the original muffle it may very well be plugged.

 
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09-24-16, 05:15 AM   #17  
I'm not sure what the spark plug electrode is but I'll figure it out and post a picture.

I don't know if it is the original muffler but it is the kind that originally came with it. Maybe the muffler is plugged but if i take the muffler off the exhaust is still dangerously hot.

 
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09-24-16, 06:02 AM   #18  
No, don't run it without a muffler, Bob. If it wasn't serviceable it would have to be replaced. Those aren't terribly expensive, though.

The electrode of the plug is the end that screws into the engine to ignite the fuel.

 
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09-24-16, 07:19 AM   #19  
Here are pictures of the plug. They didn't come out to good. The plug actually looks better than the pics. This is a new plug and has run less than 5 mins total.
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09-24-16, 08:46 AM   #20  
Other than heavier than normal deposits for only running 5 mins, that looks like a normal running engine as far as mixture.

Are you sure of the type you posted? : -0209 ?

There are several mufflers used on these engines considering the application or "type".
Page 6 of this manual shows the different mufflers and exhaust components used. I can not find type 0209 listed for any of them...from your photos a bit hard to tell but perhaps 299 or 300d? The exhaust uses NPT so creating your own configuration can easily be done with a trip to the hardware store.

If possible can you find the model number of the Vacuum itself? I am guessing it is MTD. If so the number will begin with 24 and formatted " 24*********" also need the serial number to find manuals for the unit.


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09-24-16, 11:05 AM   #21  
that is the correct number. I stopped a the small engine parts store and they don't have the muffler for this. They told me the engine is 1969. They think it could be a dirty exhaust valve so I'll try cleaning that.

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09-24-16, 11:34 AM   #22  
Ok on the type #. Did you find any numbers for the unit itself? As I mentioned I suspect it was made by MTD which I can find more specific info on provided with the numbers.
I personally don't agree with an exhaust valve since there is seems to be unrestricted release through the exhaust and no signs of excessive heat in the engine from the spark plug.

Did you check the manual and determine if any of those mufflers is what you have?
It is possible that a 90 and or extension in the exhaust is missing from original...


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09-24-16, 11:42 AM   #23  
Did you find the points/condenser on the engine and check the point gap?

 
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09-24-16, 11:48 AM   #24  
From signs of the plug it is not running lean.....
Still I would agree with cheese that if it is intended to be used to replace the mag and be done with the points.


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09-24-16, 11:59 AM   #25  
I think the module would be an improvement, but I believe I would check the point gap as it's been run and see if that may be an answer to the overheating.

 
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09-24-16, 03:45 PM   #26  
I'll have to research how to check the points. The number is right off the engine. The muffler setup is correct from all the pictures I have seen on line.

 
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09-24-16, 04:19 PM   #27  
I took the head off and here is what the valves look like. I had cleaned the top of them before i got the engine running. The intake is now black.

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09-24-16, 05:10 PM   #28  
Refer to post #12.
______________


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09-24-16, 06:50 PM   #29  
Flywheel key, Points/condenser, or too much RPM. It's one or more of these.
I was a bit curious when you said only 5 min run time on the spark plug too...as in what those 5 mins were spent doing....under any load or simply testing at idle...

Have you used it and really put it under a load yet? That impeller spinning free takes a lot of torque to get up to speed, but once there , the momentum can overide the engine if not under a load.


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09-24-16, 09:36 PM   #30  
It was not under load. Just started it a few times and let it run for a min

 
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09-25-16, 12:43 AM   #31  
Yeah, I wouldn't have expected the plug to look like that in only 5 minutes either, good catch.
Okay... soot on the plug with a red muffler says the fuel is not fully combusting in the cylinder, it is going out the exhaust and burning off there. More reason to suspect late ignition (a problem with the points and condenser or partially sheared flywheel key and it looks like the key is fine, so you're down to one thing now). I'd put a coil on it and be done with it.


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09-25-16, 07:35 AM   #32  
What does put a coil on it mean?

 
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09-25-16, 08:02 AM   #33  
The coil is one of the ignition/electrical parts. Replace the ignition coil.

If you are familiar with car engines pre-mid 70s, you are familiar with the distributor or distributor cap. On the distributor cap was one spark plug wire for each spark plug. These were located all the way around the outer edge of the distributor cap. Then there was one "spark plug looking kinda wire" right in the center of the cap. That single wire went from the center of the distributor cap to the coil. The coil was usually about the size of, or smaller than, a coke can. The coil wire was usually less than 12" long.

 
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09-25-16, 08:42 AM   #34  
the point gap was way off. maybe thats was the problem. Once i get it back together we'll see. the thing that hold the flywheel on came apart and the beraings cam out. I'm trying to get them lined up to get it together

 
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09-25-16, 09:42 AM   #35  
If the point gap was a lot wider than the spec it would have advanced the timing proportionately. That can cause over heating.

If you decide to replace the points/condenser/coil with the single module, keep in mind you'll need to shop for an ignition module and not just a coil like you have. The module will replace the points/condenser/ and coil. You'll just have a single kill wire coming out of the module to run to a switch for ground.

If you're on a tight budget and don't plan on using the machine a lot, the point setup you have may get you by.

 
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09-25-16, 10:06 AM   #36  
The point gap was too tight a .010 would not fit and it should be .020.
So that must have been the problem because the Muffler no longer gets red hot.
It seems to be running rougher not. I was adjusting the carb when i noticed the screen covering the starter clutch/flywheel was spinning. Is that supposed to spin when the engine is running. I never noticed before. I soon as i was thinking that i heard some grinding from there and shut it down. When i took the flywheel off earlier the starter clutch came apart and the ball bearings came out. When I put them back in it didn't look like the two parts where the ball bearing were match up correctly. I'm not sure how to describe it but all the balls were not it the same spot in each location when i turned the clutch. I'll have to take it apart again. should there be grease in there. It didn't look like there ever was.

 
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09-25-16, 02:36 PM   #37  
No grease in the starter clutch!!!! It must be dry and clean for the ball bearings to move freely.
The screen should mount directly to the starter, so yes it will spin with the engine.

I'm not sure how to describe it but all the balls were not it the same spot in each location when i turned the clutch
I am pretty sure I understand, I don't remember if there is one more ball than slot, or it just looks that way when you put all the balls in the housing. Ya it don't look quite right at first but you can place all the bearings in the housing, then by hand slowly turn the engine with the starter cup by had and watch the action. When you turn it CCW it should not spin the engine, CW the bearings should lock in and spin the engine.


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09-26-16, 11:25 AM   #38  
One steel ball per slot. Make sure the post that goes up into the square part of the starter is clean, rust-free, and smooth. You can put one or two drops of light oil into the hole of the square piece but no more. Otherwise it will gum up and cause problems.


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10-01-16, 12:44 PM   #39  
It' looks like the red hot muffler problem was solved by fixing the gap in the points. After doing that i got the grinding problem I already mentioned. I figured I put it back together wrong to cause the grinding so i took the starter clutch off and there were metal shavings on the threads. I dont know where that came from. I cleaned it off. I took the starter clutch apart and reset the balls. Put it back together and had a heck of a time getting it started. It ran for a couple mins with no grinding sound. It was running rough so I started turning the cab adjustment screw and it stalled out. That was the last time i could get it running. I took the spark plug out and put a little gas in there a few times and it wanted to start. The spark plug was pretty black so i replaced it and still wont start. What could be going on now

 
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10-01-16, 11:02 PM   #40  
Since you had the starter off to check the flywheel key, I would suspect the key is now sheared. That starter has to be very tight or it will shear.


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