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2024/04/03 15:23:01
SavageNature

Craftsman T2400 Briggs 33R877- Wont Start- Long story.

Briggs & Stratton 33R877 0002 G1 (2014)
Good afternoon,
This is my first post due to being new to DIY lawnmower repair.
So, I bought this mower used- it was running with blue smoke- seemed to be over filled with oil. After I got some of the oil out, changed the air filter, spark plug, & used carburetor cleaner- It was running well- No smoke a little pulsing from the throttle.
After a few weeks, I was mowing the lawn and noticed that the fuel was very low (see through fuel filter almost empty) I parked,
went and got fresh gas at the gas station (87). Filled it up. Started mowing and ran over a RV Rug. (woven thin plastic)
The mower shut down, wouldn't start. I had to pull the "pin" and push it to where I usually park the mower. Upon inspection, The sparkplug wire was off- which was odd. After I put it back on, only would backfire and not start. I also noticed an oil leak- So i replaced the gasket on the header/cylinder. I noticed the rocker arms were very loose & exhaust valve was "stuck" open due to a black ring being there, I tried to push it back in to free up the valve. (I may need to switch the valve out?) I put it all back together- didn't really space the rocker arms to perfect gap yet- waiting for this weekend to get the spacer for that. The arms looked straight. I installed a new carburetor. I was told to look out for the camshaft, but when I spin the flywheel, I get that "extra" bump.. Could it be the flywheel key? I am not sure, I didn't hit a rock- would that thin plastic be enough? Should I take out the fresh gas and get a better grade put in?
Sorry for the long story- I will be able to look at it more this weekend and post pictures pertaining to anything needed. Any help or ideas would be appreciated!!
16 comments Leave a comment
SRTsFZ6
Quote:
    "stuck" open due to a black ring being there".  
 
The flywheel may have sheared, which it's designed to to.  You May be able to 
check valve opening/piston location with the FLYWHEEL Magnet not being close. 
The flywheels not hard to remove and check..
 
Re the black ring", the intake valve ONLY, has an oil seal on the head around the valve.  That may be what your seeing. 
 
If the exhaust valve is staying partially open, you likely have a dropped(fell out) exhaust valve seat (in the head). It'll hold the valve open (partially or a lot).   It's not un-common but usually occurs from running hot or old age.  My current 18HP Briggs, freebie) had that exact failure.  It may be a bent valve as well, but in any event it should close fully...
 
 
 
2024/04/03 18:51:30
SavageNature
Thanks for your Reply!
SRTsFZ6
Quote:
    "stuck" open due to a black ring being there".  
 
The flywheel may have sheared, which it's designed to to.  You May be able to 
check valve opening/piston location with the FLYWHEEL Magnet not being close. 
The flywheels not hard to remove and check..

 -I will check the Flywheel once I get a flywheel puller.
SRTsFZ6
Quote:
Re the black ring", the intake valve ONLY, has an oil seal on the head around the valve.  That may be what your seeing.
 

 - I believe the intake valve was fine (bottom valve).
SRTsFZ6
Quote:
If the exhaust valve is staying partially open, you likely have a dropped(fell out) exhaust valve seat (in the head). It'll hold the valve open (partially or a lot).   It's not un-common but usually occurs from running hot or old age.  My current 18HP Briggs, freebie) had that exact failure.  It may be a bent valve as well, but in any event it should close fully...

 - Yes the top valve (exhaust) was open due to a metal black ring being stuck. Is this something that can be changed out without replacing the entire head? 
 

Thanks!
2024/04/04 07:42:49
SRTsFZ6
Ok, the "ring" I gather is seen when looking down the port and holding the valve open?
If so, it's the valve seat and probably a bent valve, possible damage to the piston (probably not). 
 
Taryl, has a good video (he's goofy but knows his stuff) about doing the repair (if NOT too badly damaged):
 
https://www.youtube.com/watch?v=GTEVXl0uxHg   
 
I ended up replacing the entire head on mine as it was too damaged. 
About $150 brand new on Amazon with all gaskets.
 
.
2024/04/04 07:57:30
SRTsFZ6
Re flywheel removal, you don't need a special tool...
 
I've used the below method MANY times, works great (if done properly against hard surfaces):
 
Taryl again:
https://www.youtube.com/watch?v=SYVjw7fw8RU 
 
And yes, the head has to come off for the valve seat. The valve seat itself is not available from Briggs.
If not tore up, you may be able to re-use it... As long as you get an air tight seal once assembled at the
valve.   
 
When (if) re-assembled, install the spark plug, head off and upside down. Put a thin liquid inside the combustion chamber and watch for any leakage from the chamber BACK into the runner (past the valves).
 
 
.
 
 
.
 
 
.
 
2024/04/04 07:59:59
SavageNature
Thanks for these helpful answers and tips!
I will be attempting some of these this weekend, I really do appreciate the knowledge and time given pertaining to my issue!
2024/04/04 08:31:28
SRTsFZ6
Been there, done that!!  
 
It was a freebie Toro Zero turn, for free!   Don't have much $ in it, been about 3 years
with me.... Runs better than new (2005 model)  !!
 

 
 
 
 
 
2024/04/04 08:36:01
SavageNature
That was a heck of a deal! Looks very nice!
2024/04/04 12:14:02
SavageNature
SRTsFZ6 - Thanks for all of your help! Yes I seen a few of Taryl's vids and he is wild!
When I took the valve head off, it seemed as though the ring reset itself, which was odd, so I tried to make sure to make it tight. cleaned up in there pretty good.
I sprayed starting fluid in the actual chamber before reattaching the intake tube. Once assembled, it started up!
The starter sounded a bit rough like it was getting stuck on one of the cranks..(replace?) Turned it off, and it would only start with more fluid the second time- after cutting the entire back yard. after the cutting of the front it started up fine. And honestly, I think the engine is running way better with the new carburetor that I put on previously. (do i need to tune that?) but it is running strong, no more throttle pulsing. 
If the valve ring comes off again, I may just buy a new part due to "resetting" a second time may be an issue. We will see!
Thanks for all of your help!!
2024/04/08 08:24:31
SRTsFZ6
That's great!
 
Re carb tuning, there really isn't any adjustment of the carb itself so don't worry about that.
 
When researching my "issue", I learned the exhaust valve seat can come out of the head due to old 
age AND / OR overheating.  My machine didn't have any debris in the cooling fins but was over 15 years old and not maintained well...
 
Taryl does have a video of re-installing the seat, then "staking" the aluminum around seat(with a punch, indenting the aluminum to help hold the seat better).  Mine was way beyond that..  
 
Did you happen to check for fluid leakage from the valve with the head held upside down or lap in the valve?  
 
.
2024/04/08 18:25:23
SRTsFZ6
From a customers machine:
 
 
2024/04/08 18:28:07
SavageNature
SRTsFZ6
That's great!
 
Re carb tuning, there really isn't any adjustment of the carb itself so don't worry about that.
 
When researching my "issue", I learned the exhaust valve seat can come out of the head due to old 
age AND / OR overheating.  My machine didn't have any debris in the cooling fins but was over 15 years old and not maintained well... 

 
Yes, I should clean up around my fins- a bit of debris is absolutely present (CAKED around). I was looking at engine cleaners on amazon. -Any suggestions? or just get a wire brush and go to town?
 
SRTsFZ6
Taryl does have a video of re-installing the seat, then "staking" the aluminum around seat(with a punch, indenting the aluminum to help hold the seat better).  Mine was way beyond that..  

 
Yes, I seen the video that you requested which helped my secure the seat. This helped a lot!
 
SRTsFZ6
Did you happen to check for fluid leakage from the valve with the head held upside down or lap in the valve?  

 
I poured some gas in it to and held it upside down and did not notice any leakage. The valve seemed to be in good shape.
 
ALSO- What a crows nest on that thing! woah!
2024/04/09 10:20:24
SRTsFZ6
Yep, I wasn't expecting that mess.  
 
Re cleaning under the cover.  
 
Use compressed air if you have it or a vacuum and suck what you can from it.
 
Brake cleaner and a paint (or parts cleaning) brush works great for removing all the nasty's.
Use it on the exterior of the carb, linkages, intake manifold, etc.   Remove the air filter as you don't want crap flushed into that (cover up the intake opening).
 
As a side note, I use left over gasoline (old fuel from a customers machine) , squirted from a bottle onto the unit (a little at a time) to remove the heavy stuff.  The brake cleaner will remove all contaminates. 
 
Just an FYI, I've found carb cleaner to much more aggressive in cleaning and definitly DON'T USE IT near any rubber parts, seals... The rubber, most of the time, will swell and not fit anymore...
 
.
2024/04/09 15:40:20
SavageNature
I will use a shop-vac along with some brushes at first and work down the debris. (old crushed up acorns/organic matter & grime) How i bought it. I plan on taking very good care of this thing!
Good tip on the old gasoline in a spray bottle- I will have to use that!
I agree on the carb cleaner being more aggressive and will not use it for cleaning.
Thanks for all of your help, I'll try to post pictures of my mower that you helped fix!
2024/04/10 08:27:59
SavageNature
Here it is! 
Like I said, bought used- A little fading on the hood and the seat is a bit rough.
2024/04/11 15:15:31
SRTsFZ6
Looks fine!!!
2024/04/12 07:36:20

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