Carb flooding no matter what I do...

[electrycmonk]

This kind of fuel back fogging out the carb is excessive valve overlap "cam timing" or late ignition timing. Check flywheel key.

so both you and @bertsmobile1 point to checking the valves and the ignition timing marks....

(_) homework #3 and now i think i have a new learning curve ahead of me....
(_) Find the service manual and download it from here? PDF? Unless one of y'all can give me a shortcut link?

 

[Scrubcadet10]

How new is the fuel line?

 

[hlw49]

I agree on the valve problem could be a worn out cam any way the thing looks to be blowing back out the carb. You know if you have the equipment you could do a cylinder leak down test and if it is a valve problem it will tell you. But not if the exhaust valve is staying close and blowing exhaust back out the intake. Could just pull the heads off and check the valves are working. You know I have seen those old opposed twins wallow the valve seat out of them.

 

[Scrubcadet10]

flathead clearances close up over time..even heard from star tech on some having Negative clearance.. I.E. valve held slightly open.

 

[bertsmobile1]

View attachment 57552

I guess the "Carb throat" you speak of would = the "Red circle" i drew then, yes?

Excellent,
Now we are getting some where
The "brass straw" ( blue arrow) is the air vent .
In order for fuel to come out of a carb bowl, air has to get in.
When we had fewer idiots in government and more people who understood things, carburettors had overflows that dripped out of a tube under the engine so you could see from 100' away that the bowl was overflowing.
Now this has to be internal so they overflow through the air vent like yours is doing.
So first job is to remove the carburettor and fix the float valve that is not cutting off the fuel supply.
There were a couple of 1/2 decient you tube links to sites that are good enough.
If the float is cutting off the fuel then we need to look at what is causing the fuel line to be over pressurised .

Next problem
Fuel mist coming out of the carb throat , Red circle .
When the piston gets to the end of the intake stroke it rises a bit before the inlet valve closes .
If the inlet valve does not close fully as the piston rises it will pump most of the fuel that was in the cylinder back out through the carburettor .
It is usual to see a a little of this particulalry at cranking speeds because there is a mechanism that holds the inlet open a bit longer at low speeds to decompress the engine so the starter can crank it fast enough to start.
For the above mentioned idiot law makers, in the old days they held the exhaust open.
Now days they hold the inlet open so in theory the gas goes backwards through the carb and then get sucked back into the engine on the next stroke.
In practice this does not happen, but don't tell the pen pushing experts this .
SO you have a couple of likely suspects hear.
1) failed ACR ( automatic Compression Release ) fairly rare
2) inlet valve hanging open , fairly common
Usual reasons for No 2 were outlined back in the previous post .
If you have no idea how to check these things then tell us.
Plenty here quite willing to walk you through the processes just so long as we know what you need to know.

 

[electrycmonk]

How new is the fuel line?

*feels new enough, its reasonably flexible and the screw down clamps do their job with no fuel leaking out at the clamps.

I have stiffer fuel line on a different, fully functional mower currently. Because? - If it ain't broke, don't fix it.

 

[Scrubcadet10]

Okay, reason i asked is because sometimes the lines can come apart internally and those rubber bits can jam up the float and cause flooding.

 

[electrycmonk]

Excellent,
Now we are getting some where
The "brass straw" ( blue arrow) is the air vent .
In order for fuel to come out of a carb bowl, air has to get in.
When we had fewer idiots in government and more people who understood things, carburettors had overflows that dripped out of a tube under the engine so you could see from 100' away that the bowl was overflowing.
Now this has to be internal so they overflow through the air vent like yours is doing.
So first job is to remove the carburettor and fix the float valve that is not cutting off the fuel supply.
There were a couple of 1/2 decient you tube links to sites that are good enough.
If the float is cutting off the fuel then we need to look at what is causing the fuel line to be over pressurised .

Next problem
Fuel mist coming out of the carb throat , Red circle .
When the piston gets to the end of the intake stroke it rises a bit before the inlet valve closes .
If the inlet valve does not close fully as the piston rises it will pump most of the fuel that was in the cylinder back out through the carburettor .
It is usual to see a a little of this particulalry at cranking speeds because there is a mechanism that holds the inlet open a bit longer at low speeds to decompress the engine so the starter can crank it fast enough to start.
For the above mentioned idiot law makers, in the old days they held the exhaust open.
Now days they hold the inlet open so in theory the gas goes backwards through the carb and then get sucked back into the engine on the next stroke.
In practice this does not happen, but don't tell the pen pushing experts this .
SO you have a couple of likely suspects hear.
1) failed ACR ( automatic Compression Release ) fairly rare
2) inlet valve hanging open , fairly common
Usual reasons for No 2 were outlined back in the previous post .
If you have no idea how to check these things then tell us.
Plenty here quite willing to walk you through the processes just so long as we know what you need to know.

Alright, @hlw49 , @Scrubcadet10 & @bertsmobile1 I'm gonna say here early... before i goto bed.

let me see the video links to the valve checking.

A leak down test huh? I do honestly have access to a friends from their shop. these screw in at the sparkplug hole normally right? (for diesels i think its screwed into the injectors hole?)

I've rebuilt 5 80's old school subaru's, 1981 Honda CB900c, and a few classic muscle car engines but, I haven't torn into a head or engine this significant in a decade. So show me to the thread where someone else was "Walked thru it." and I will gladly bow my head in fully owning my mental rustiness here and now.

side note this evening I have been troubleshooting our NAS and struggling with the fear of a HardDrive failure that didnt have a solid "backup" done to it in too long.

I'll be back at it tomorrow after lunch finishing the NAS repairs... the Mower will likely be a tuesday or wednesday "laying on of the hands" but, tomorrow and tuesday will be the mental walk with yall...

night night and thanks in advance.

 

[slomo]

Find the service manual and download it from here? PDF? Unless one of y'all can give me a shortcut link?

http://faculty.missouri.edu/~schumacherl/276781SingleCylinderOHV.pdf

 

[Joed756]

Using the info Slomo provided, check your valves.