Help! Briggs 14.5 hp keeps shutting off

[Klutch9]

I've got a 9 year old 14.5 hp briggs OHV motor on my yard tractor. the last few times i've mowed the lawn, once it reaches operating temperature it sputters like rhythmically almost, like the same pattern for a few seconds, then it slowly dies and shuts off. sometimes it'll start back up, sometimes i have to let it sit for a few minutes before it'll actually fire, but even if i'm able to get it running again, it still dies again shortly after.

The engine has fresh oil (no oil filter on my engine), a clean air filter, clean fuel lines and a perfectly clean fuel filter, new gas, valvetrain gaps are in proper spec... any ideas as to why it's doing this? is the carb dirty or clogged possibly? i ran some seafoam in the gas sometime within the past year, but maybe something got stuck in there? What gets me is that it cold starts right up every time, even after sitting for almost 2 weeks at a time, so im thinking that the heat is affecting something.

 

[talker]

My lawnmower does that sometimes.

Suprizenly, it is caused by a small leak colse to the exaust in the front, which eventually causes it to over heat. (In my case, anyway.)


All I do is let it set for 5 min, drive it to the water hose, and spray the [censored] out of it, then use degreasser.


Then shes good to mo!!!

 

[Klutch9]

so you have a hole in your exhaust? because my tractor does too... right on the top of the muffler, its not big, but shoots right back up onto the engine. maybe thats it...

 

[talker]

Oh darn. I ment it has a small OIL leak by the exaust causing it to overheat.

 

[Mamala Bay]

It's a sign that your coil is going bad. The coil will kick out when it heats up. Sounds like an electrical thing spark plug sputters. I'd check the spark plug when it kicks out and check if you got a spark. If there is none try another spark plug that you know is working. Could be a bad spark plug also.

 

[Turk]

Ha - I just walked back from my neighbor across the street and it's doing the SAME THING!

How about the fuel pump...? That's what he think it is on his...

 

[Mamala Bay]

Originally Posted By: Klutch9
I've got a 9 year old 14.5 hp briggs OHV motor on my yard tractor. the last few times i've mowed the lawn, once it reaches operating temperature it sputters like rhythmically almost, like the same pattern for a few seconds, then it slowly dies and shuts off. sometimes it'll start back up, sometimes i have to let it sit for a few minutes before it'll actually fire, but even if i'm able to get it running again, it still dies again shortly after.


This sounds like a sign of a bad coil is going out.

Coil can kick out without any sign but also they can show a sign. This usually happens when it heats up at operating temp and running at that temp for while. When the coil cools off it will produce a spark but once engine heats up again the coil kicks out.

When your engine kicks out CHECK for a spark immediately before the coil cools off. Also have another spark plug you know that is working and check for a spark. This will eliminate two problems, a bad coil or a defective spark plug.

 

[JimmyChainsaw]

If someone brought a mower into me with those symptoms the first thing to check is the fuel cap.All small Briggs vent the tank through the cap.
It would be a very rare thing for the ignition to fail as suggested,they normally go or dont go regardless of temp.

 

[Mamala Bay]

Originally Posted By: JimmyChainsaw
If someone brought a mower into me with those symptoms the first thing to check is the fuel cap.All small Briggs vent the tank through the cap.
It would be a very rare thing for the ignition to fail as suggested,they normally go or dont go regardless of temp.


Most small engines fuel caps are no different then Briggs. If it's the fuel cap the OP should unscrew the cap to release the vacuum in the fuel tank. If the engine starts well its the fuel cap.

I'm almost 100% sure this is a sign of a coil that is going bad and needs to be replace. I've experience almost identical symptoms as what the OP described.

 

[Klutch9]

hmm... i suppose it could be the coil. although i've never had nor heard of a small engine losing a coil, so it must be extremely rare. i wouldn't rule it out though. right now i dont feel like paying for a new one, if that is actually it. thank goodness the lawn isn't growing as much now!

i still have a small push mower to get the job done.

 

[greenaccord02]

Is it a float carb? Check that the float isn't leaking and that the needle isn't clogged up. That'll cause similar stuff and it won't take a minute to check.

 

[Mamala Bay]

Originally Posted By: greenaccord02
Is it a float carb? Check that the float isn't leaking and that the needle isn't clogged up. That'll cause similar stuff and it won't take a minute to check.


If the float or needle was clogged how did the engine start?

 

[greenaccord02]

If fuel is only able to get in by a trickle then it would run for a short time and then die out. Waiting for a few minutes would allow the fuel in just enough for the engine to run again for just a moment before dying. This is much more common than a bad coil.

 

[Mamala Bay]

Originally Posted By: Klutch9
hmm... i suppose it could be the coil. although i've never had nor heard of a small engine losing a coil, so it must be extremely rare. i wouldn't rule it out though. right now i dont feel like paying for a new one, if that is actually it. thank goodness the lawn isn't growing as much now!

i still have a small push mower to get the job done.


good for you. if your lawn is a playground well i understand.

 

[Klutch9]

Originally Posted By: greenaccord02
If fuel is only able to get in by a trickle then it would run for a short time and then die out. Waiting for a few minutes would allow the fuel in just enough for the engine to run again for just a moment before dying. This is much more common than a bad coil.


usually after it dies i can let it sit for a minute and it starts back up and runs again... but lousily, and dies again soon thereafter. but last week it somehow ran fine after dying once, and i mowed the entire lawn.

 

[c3po]

Originally Posted By: Mamala Bay
Originally Posted By: Klutch9
hmm... i suppose it could be the coil. although i've never had nor heard of a small engine losing a coil, so it must be extremely rare. i wouldn't rule it out though. right now i dont feel like paying for a new one, if that is actually it. thank goodness the lawn isn't growing as much now!

i still have a small push mower to get the job done.


good for you. if your lawn is a playground well i understand.


My Dad went through 3 coils over 13 years on his MTD Tractor that had a 18 HP Briggs Engine.