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Spark plug gets gas fouled every cold start

#1

S

steves snapper

Spark plug gets gas fouled every cold start

Intek 12.5HP I mow twice a month. When I go to crank her up, I press the throttle all the way forward which is the choke (I’ve always cranked her this way) she won’t start bc the spark plug is covered in gasoline.

Should I not be choking an just leave the throttle at the position I run her at (just a bit lower than WOT probably ¾.)



I now air out these gas fouled plugs an am able to reuse on a rotation, would prefer not have to be forced to swap a plug twice a month.

Pls recommend a fix maybe turn back the carburetor a bit.thanks for advisefirstcut.jpg


#2

sgkent

sgkent

most likely you have a fuel or carburation problem. Check the oil too to be sure it isn't filled with gasoline that has been leaking down while it sits.


#3

Scrubcadet10

Scrubcadet10

air filter clean?


#4

S

steves snapper

sgkent said:
most likely you have a fuel or carburation problem. Check the oil too to be sure it isn't filled with gasoline that has been leaking down while it sits.
Click to expand...
prior to finishing mowing, what I do is turn the fuel petcock off an run the engine till dry. how can I tell if gas is in the oil?thanks sgkent


#5

S

steves snapper

Scrubcadet10 said:
air filter clean?
Click to expand...
I can check the air filter IIRC I had a tiny bit of dirt in it at beginning of April. I mow from April though mid Dec. thanks

Scrubcadet10​



#6

A

Auto Doc's

Pull the upper cover and air cleaner off/ out of the way then operate the throttle to verify the choke is working freely and releasing properly. The choke plate lever may be hanging up from excess dust or grass clippings.

This design was a little moody about the choke hanging up.


#7

S

steves snapper

the throttle has always been a bit tight when pushing forward for choke it's been like that for over 12 years. never paid much attention to it.
I will take a look at the carbs. plates. the owners an service mauel kindof skip over carburetor. when I push the throttle lever forward for the choke will I see the plate open extra wide an when I pull backward for regular throttle the plate will close a bit? thanks AutoDocs


#8

M

MParr

A throttle cable adjustment or new throttle cable might do the trick. The throttle plate should close all the way on full choke.


#9

S

slomo

steves snapper said:
how can I tell if gas is in the oil?
Click to expand...
Think about this one a bit.



Pull the oil dip stick out. Use that thing on the front of your face. Still need help? :geek: Sorry I had to.


#10

S

slomo

Pull the top engine cover off. Use your eyes to make sure the carb linkage is working properly. About 3/4 down on the throttle, should be a detent. That is where the choke plate starts to close. Throttle lever all the way down is full choke.

Good job on using the fuel shut off valve.

While you are there, CLEAN your cooling fins. This is a yearly thing on ALL mowers. Compressed air, old paint brush, leaf blower, screw drivers......... Clean the fins and block like a new engine.


#11

M

MParr



#12

S

steves snapper

I always check the oil before every mow. OK I will smell the oil for gas. come to think about it the oil doe's appear to be a tad thiner.
this reminds me of the Yamaha outboard engine they have a term called making oil but I think water is being added to oil.

next mow in a couple weeks I'll take a close look down the throttle plate of carb. an report back.
when you say clean are you say to clean cylinder head fins? thanks Slomo


#13

S

steves snapper

MParr said:
Click to expand...
good video you know my cable has been real constrictive the closer to choke I move it. actuely it's never been smooth. this for over 12 years. thanks MParr.


#14

S

slomo

steves snapper said:
when you say clean are you say to clean cylinder head fins? thanks Slomo
Click to expand...
Yes sir. Head and block. All around the engine. Videos below.





#15

The Brain

The Brain

I attempted to mow the leaves today. same old stuff fuel is leaking out it's soaked the spark plug wire, an made a puddle on the cylinder head. now I'm concerned w/ an explosion. please advise and thanksgasoline leaking on head.jpg


#16

A

Auto Doc's

I recommend you remove the ignition coil and clean everything really well with brake cleaner. Once clean, look for signs of cracking in the casting. This is oil creeping from somewhere such as a crack, or casting porosity pinholes.

It may also help to apply shop air pressure through the plug hole with both valves closed.


#17

M

MParr

Clean all of that up and pull the plugs.
Get some pictures of the plugs and post them.
That's a long way for fuel to go and settle on the cooling fins.


#18

The Brain

The Brain

Auto Doc's said:
I recommend you remove the ignition coil and clean everything really well with brake cleaner. Once clean, look for signs of cracking in the casting. This is oil creeping from somewhere such as a crack, or casting porosity pinholes.

It may also help to apply shop air pressure through the plug hole with both valves closed.
Click to expand...
I neglected to mention when I turned her over to start battery was at 12.05VDC barely turned her over but I did hear leaking compression. I will clean. when you say shop air into the spark plug hole how much PSI an am I sparying w/ soapy water like a innertube repair? w/ this much fuel all over the engine exspecialy next to the coil thats an explosion waiting to happen correct? thanks Auto Docs


#19

The Brain

The Brain

MParr said:
Clean all of that up and pull the plugs.
Get some pictures of the plugs and post them.
That's a long way for fuel to go and settle on the cooling fins.
Click to expand...
I attemptrd the start up over 24 hours ago so I assume the gasoline on the plug has evaporated? the fuel on the spark plug wire dryed yesterday. strange the cylinder cooling fins are filled w/ gasoline.can I remove the plug now for these images you request?

the previous fuel leaking problem was the exhaust manifold cracked right where it's bolted to the head. remember I swapped the old manifold on which resolved that leak. thanks MParr


#20

M

MParr

The spark plugs will be wet with fuel and fairly clean, if there is that much fuel getting into the cylinders. If that's the case, I'm surprised that you haven't experienced a hydro-lock situation.
I just can't imagine that much fuel on top of the cooling fins coming from inside of the engine. Oil can certainly show up in that area.
I had Kawasaki Mule that would carbon foul the plugs. It eventually got worse. It progressed and hydro-locked the engine. I pulled the plug and cranked it over. Gasoline shot out of the spark plug hole. I changed the carburetor, plug, and traded that nightmare.


#21

The Brain

The Brain

MParr said:
The spark plugs will be wet with fuel and fairly clean, if there is that much fuel getting into the cylinders. If that's the case, I'm surprised that you haven't experienced a hydro-lock situation.
I just can't imagine that much fuel on top of the cooling fins coming from inside of the engine. Oil can certainly show up in that area.
I had Kawasaki Mule that would carbon foul the plugs. It eventually got worse. It progressed and hydro-locked the engine. I pulled the plug and cranked it over. Gasoline shot out of the spark plug hole. I changed the carburetor, plug, and traded that nightmare.
Click to expand...
you know I hate to think about it but I was having a no spark issue an couldn't find the spark tester so I removed the spark plug an placed the spark plug near the cylinder head cranked her over to see if I had spark. what I had was a huge fireball from all the fuel shooting out the spark plug hole scared the crape out of me.
I never thought there would be that much fuel shooting out the sp hole. there's definitity something wrong w/ the fueling.

I also neglected to mention the cylinder head swap from the orginal engine. remember my thread about adjusting the valves? anyway I reused some of the old orginal engines valves. I also reused the old cylinder head gasket. pretty sure I tightened the cylinder head down tight. tightening from inside to outside in like 3 pass's.

I'll clean an inspect real close, if I don't see any visiable cracks then remove head an inspect the head gasket. will report back. thanks MParr


#22

M

MParr

With what you just described, you definitely have a carburetor problem.
I got a good soaking after pulling the plug on the Kawasaki Mule. It's a good thing the spark plug wasn't connected to the plug wire.


#23

ILENGINE

ILENGINE

MParr said:
With what you just described, you definitely have a carburetor problem.
I got a good soaking after pulling the plug on the Kawasaki Mule. It's a good thing the spark plug wasn't connected to the plug wire.
Click to expand...
Doesn't matter if the spark plug is connected or not. I have had 2 over the years where the spark plug was sitting on the work bench and cranked the engine over and had them static discharge ignite. I will not crank an engine over with a flooded cylinder if I can avoid it. Will blow the cylinder out with compressed air if available.


#24

Tiger Small Engine

Tiger Small Engine

The Brain said:
you know I hate to think about it but I was having a no spark issue an couldn't find the spark tester so I removed the spark plug an placed the spark plug near the cylinder head cranked her over to see if I had spark. what I had was a huge fireball from all the fuel shooting out the spark plug hole scared the crape out of me.
I never thought there would be that much fuel shooting out the sp hole. there's definitity something wrong w/ the fueling.

I also neglected to mention the cylinder head swap from the orginal engine. remember my thread about adjusting the valves? anyway I reused some of the old orginal engines valves. I also reused the old cylinder head gasket. pretty sure I tightened the cylinder head down tight. tightening from inside to outside in like 3 pass's.

I'll clean an inspect real close, if I don't see any visiable cracks then remove head an inspect the head gasket. will report back. thanks MParr
Click to expand...
Charge battery, 12.05 volts is flat.
Remove carburetor and address the leaking needle and seat issue. Install fuel shut off valve for backup.


#25

M

MParr

ILENGINE said:
Doesn't matter if the spark plug is connected or not. I have had 2 over the years where the spark plug was sitting on the work bench and cranked the engine over and had them static discharge ignite. I will not crank an engine over with a flooded cylinder if I can avoid it. Will blow the cylinder out with compressed air if available.
Click to expand...
I won't do it again.
That Mule had great compression. 😂
The Nikki carburetor was horrible.


#26

The Brain

The Brain

I can remove an replace the carb. I’d probably mess up trying to rebuild a carb.



All I see that’s available is a carb replacement from ebay. a carb part# would be a big help.

219907-0131-B1 - Briggs & Stratton Vertical Engine carburetor parts NA image



top of carburater image linkage pointed frontward
top of carburater.jpg


right side of carburater

right side of carburater.jpg

full choke throttle plate closed

full choke throttle plate closed.jpg

throttle backed down (giving little fuel)

plate open

throttle backed down (giving little fuel)plate open.jpg



cable moving linkage toward front



cable moving linkage left

carbuater linkage.jpg
can I turn key switch to on (not ignition) an expect the fuel pump to pump fuel where I can observe where she's leaking?

thanks Guys for advising


#27

The Brain

The Brain

Update:I turned the key switch to ignition an observed fuel shooting straight up.this fuel appeared to be coming out the cylinder head but I didn’t see any cracks. I removed the cylinder head and found a damaged or blown head gasket it doesn’t appear to be blown all the way though just a bit of a layer.
blown head gasket.jpg
blown head gasket opposite side.jpg

There is a carbon stain on the cylinder head. Image
blown head gasket stain on head.jpg
I assume all this compression being released is why the fuel wasn't getting burned thus the gas fouling the spark plugs. I was able to get away w/ swapping in new plugs bc the gasket wasn't completely releaseing compression I'm thinking.

how doe's this look https://www.amazon.com/gp/product/B08D8QP9NB/ref=ox_sc_act_title_1?smid=A2RFO9WR3VK6AB&psc=1
can I rub the head and block w/ steel wool before swapping in the new gasket? thanks


#28

M

MParr

Are you using an electric fuel pump?


#29

A

Auto Doc's

Need a better picture of the head.

You can carefully get the left-over material off the head with a razor blade.

After that you need to resurface the gasket face of the head using a true flat surface like a tempered glass table and 400 grit wet/dry sandpaper. Scrub the head gently across the sandpaper and you might be surprised how much sanding will be needed to re-true the gasket surface.

Sand until the entire gasket surface is clean aluminum.

The block surface will also need some light cleaning.


#30

The Brain

The Brain

MParr said:
Are you using an electric fuel pump?
Click to expand...
not sure about the fuel pump, don't even know where it's located. when I turned the ign. key the fuel shoot up over ten feet.then when dissassembling the head seamed like the whole cylinder was filled w/ fuel.


#31

The Brain

The Brain

Auto Doc's said:
Need a better picture of the head.

You can carefully get the left-over material off the head with a razor blade.

After that you need to resurface the gasket face of the head using a true flat surface like a tempered glass table and 400 grit wet/dry sandpaper. Scrub the head gently across the sandpaper and you might be surprised how much sanding will be needed to re-true the gasket surface.

Sand until the entire gasket surface is clean aluminum.

The block surface will also need some light cleaning.
Click to expand...
I'll take a good image of head. it felt smooth around the carbon stain. I don't have a tempered glass table. I do have a piece of plexie glass about 1/8" thick x 2'. what do you think about the amazon gasket?


#32

M

MParr

The Brain said:
not sure about the fuel pump, don't even know where it's located. when I turned the ign. key the fuel shoot up over ten feet.then when dissassembling the head seamed like the whole cylinder was filled w/ fuel.
Click to expand...
It certainly sounds like you have an electric fuel pump mounted on your engine. A standard pulse fuel pump will not pump fuel unless the engine is turning over. Follow your fuel line from the carburetor. A pulse fuel pump will look like this. 👇

Amazon.com: Briggs and Stratton Genuine 808656 Mechanical Fuel Pump by Briggs & Stratton : Automotive

Amazon.com: Briggs and Stratton Genuine 808656 Mechanical Fuel Pump by Briggs & Stratton : Automotive
www.amazon.com


#33

Tiger Small Engine

Tiger Small Engine

MParr said:
It certainly sounds like you have an electric fuel pump mounted on your engine. A standard pulse fuel pump will not pump fuel unless the engine is turning over. Follow your fuel line from the carburetor. A pulse fuel pump will look like this. 👇

Amazon.com: Briggs and Stratton Genuine 808656 Mechanical Fuel Pump by Briggs & Stratton : Automotive

Amazon.com: Briggs and Stratton Genuine 808656 Mechanical Fuel Pump by Briggs & Stratton : Automotive
www.amazon.com
Click to expand...
It is a Nikki carburetor from the looks of pictures. If you can’t tell a pulse fuel pump from an electronic fuel pump, I would suggest going to a shop for help. Why would an electronic fuel pump be on a carbureted engine?!


#34

M

MParr

Tiger Small Engine said:
It is a Nikki carburetor from the looks of pictures. If you can’t tell a pulse fuel pump from an electronic fuel pump, I would suggest going to a shop for help. Why would an electronic fuel pump be on a carbureted engine?!
Click to expand...
We aren't getting all of the details.
Fuel delivery and fuel metering seems to be the main problems. An electric fuel pump will definitely flood out the engine and carburetor. Fuel is bypassing the needle and seat. There could be a problem with the float too.
Looking at the overall setup of the Rear Engine Snapper, the fuel tank height is above the carburetor height. If that is how it actually setup, there is no need for a fuel pump. Gravity feed is all that's needed. That takes us back to the carburetor.


#35

The Brain

The Brain

MParr said:
Looking at the overall setup of the Rear Engine Snapper, the fuel tank height is above the carburetor height. If that is how it actually setup, there is no need for a fuel pump. Gravity feed is all that's needed. That takes us back to the carburetor.
Click to expand...
Here’s the cylinder head after blown head gasket. not seeing metal damage image

cylinder head after blow head gasket.jpg
cylinder head after blow head gasket2.jpg

I had to use the parts engine head from orginal head.

Replacement engines head damaged under rocker arm mount. I assume it’s trashed image

orginal head damaged under rocker arm mount.jpg

Aditionaly I do smell a bit of fuel in the oil. Thanks for advising.

edit as far as the fuel pump goe's I previously mentioned I don't even know where it's located. I belive MParr is correct about the gravity feed fuel.
I did turn the key switch to ignition turning engine over this is when I observed the fuel shooting straight up real high.


#36

The Brain

The Brain

Tiger Small Engine said:
It is a Nikki carburetor from the looks of pictures. If you can’t tell a pulse fuel pump from an electronic fuel pump, I would suggest going to a shop for help. Why would an electronic fuel pump be on a carbureted engine?!
Click to expand...
do you have a part# for this carb. thanks


#37

M

MParr

Is this your correct engine number?
219907-0131-B1 - Briggs & Stratton?
If not, please list the model number and serial number.


#38

The Brain

The Brain

MParr said:
Is this your correct engine number?
219907-0131-B1 - Briggs & Stratton?
If not, please list the model number and serial number.
Click to expand...

yes that is the correct engine# as ingraved on the valve cover.

engine#cu.jpg


#39

The Brain

The Brain

the amazon gasket appears to be the correct gasket however the bot is confused as usalesnapper gasket bot is confussed.jpg.


#40

M

MParr

The Brain said:
yes that is the correct engine# as ingraved on the valve cover.

View attachment 72324
Click to expand...
I believe that this is your carburetor. Some of the others on here can confirm.
shop.briggsandstratton.com

Briggs & Stratton 593432 Carburetor

Genuine replacement carburetor for single cylinder engines. This OEM part is used on select 21 cu. in. vertical OHV engines and ensures proper fit and performance to maintain the life of your Briggs and Stratton engine. Many parts look similar, so it’s crucial to ensure you’re choosing the right...
shop.briggsandstratton.com shop.briggsandstratton.com
@ILENGINE
@Auto Doc's


#41

The Brain

The Brain

thanks on carb part# what is correct part# for head gasket?


#42

M

MParr

The Brain said:
thanks on carb part# what is correct part# for head gasket?
Click to expand...
I come up with a B&S part #273280S


#43

The Brain

The Brain

yeah thats what I came up w/ from parts tree. could a faulty carburater flooding the cylinder create to big of an explosion which ruined the head gasket?
BTW I have a spare carb from orginal engine.but am uncomfortable dissassembleing a carb. I'd rather swap in a replacement but then I'll have to figure out how to adjust. or can I count the # of turns each screw? thanks
cylinder head gasket.jpg


#44

M

MParr

I suggest that you get the B&S carburetor. It's a crap shoot with aftermarket stuff.
Replace all of your fuel lines and your fuel filter. Adjust the valves after fitting the new head gasket.
I don't think that will have too much of a problem with setting up your carburetor.


#45

A

Auto Doc's

The Brain said:
I'll take a good image of head. it felt smooth around the carbon stain. I don't have a tempered glass table. I do have a piece of plexie glass about 1/8" thick x 2'. what do you think about the amazon gasket?
Click to expand...
Plexiglass is not stabile and usually not true "flat" level. You need a perfectly solid flat surface has possible to get the head truly flat on the gasket mating surface.

Amazon just sells the gasket; they don't make them. I have not had any problems using them though.

I advise you to get a B&S small engine repair manual that cover your model. They can be found as online downloads. They are much cheaper than guessing and making mistakes.


#46

The Brain

The Brain

This is definity a carb. Related problem which I believe lead to the blown head gasket.


I just found out how the needle/seat and sticking float can produce fuel flooding cylinder an get into crankcase. I will remove carb. Bowl an inspect float for holes if float is full of fuel it won’t float an needs replacing proceeding on test the float blowing into upsidedown carb. Result float is blocking flow which means it’s working.



Then w/ carb rightside up blow again if float is functioning properly it should alow flow so when I blow it should flow though carb. Maybe I can get away w/ just cleaning the needle/seat an possiably replace the float.



So I believe the carbs float is malfunctioning bc I do smell fuel in oil an I assume the gasket blew bc of to much fuel inside the cylinder.
how bad can the el cheapo amazon carbs be?


will report back an thanks.


#47

M

MParr

How bad can the cheapo Amazon carbs be? It's a crap shoot. If you are planning on keeping the mower, put on a Briggs carburetor. You will thank yourself later.


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