Sabo lawnmower with Briggs & Stratton engine won't start when warm
- Thread starter Raiden
- Start date
So, if you use water to check for leaks, does the motor slow if it's sucking water, or do you just see it being sucked in?
Parts add up. That is why you need to test them before replacing. I have no problem with replacing a spark plug at $3.50-$4.00 if you are unsure. But make sure you have a quality plug. There are a lot of cheap counterfeit plugs on the internet. Buy your plugs at a Brick and Mortar store. You should use a RJ19LM or J19LM Champion. This is what Briggs designs the engine with. They come with different versions of that plug from the Factory, but it is the basic base line plug that will work well. The non resistor (no R prefix) plug will give a little bit stronger spark. For some reason, from the Factory they always use the R. I do not know Briggs thoughts on this. I won't guess.
If you cleaned the carb as you said, the float is at the right position, It does not leak. It should be fine. You do not need a new one. Did you replace the O-ring seal or confirm it is good? They usually last a very long time. The Chinese cheap carbs are a crap shoot. On top of that the bowls rust very easily. I have seen 2 to 3 year old ones with rust in the bowls.
It appears that you set up the thermostat sail correctly from what I can see in the video. If the sail spring is not the original it may be too light. This is a long shot. I am guessing at what else may be your issue.
It seems if you where at 1/2 choke your issue would go away. As slow mo said you should not run long with the shroud off for long. It is not really an accurate test as the cooling/heating of the engine is altered by it being off.
If you cleaned the carb as you said, the float is at the right position, It does not leak. It should be fine. You do not need a new one. Did you replace the O-ring seal or confirm it is good? They usually last a very long time. The Chinese cheap carbs are a crap shoot. On top of that the bowls rust very easily. I have seen 2 to 3 year old ones with rust in the bowls.
It appears that you set up the thermostat sail correctly from what I can see in the video. If the sail spring is not the original it may be too light. This is a long shot. I am guessing at what else may be your issue.
It seems if you where at 1/2 choke your issue would go away. As slow mo said you should not run long with the shroud off for long. It is not really an accurate test as the cooling/heating of the engine is altered by it being off.
It slows silly. What do you think it would do?? LOL
If you add enough water and RPM's, will steam clean the inside of the combustion chamber and valves too.
sgkent
Lawn Addict
at rpm the water will, as slomo stated, and I suspect the trolling post asked 
steam clean the inside of the combustion chamber. GM used water as means of knocking excess carbon loose for years. A very slow drizzle is all an engine can tolerate before it stalls. That is because it is mixed with the fuel mixture when it is poured or injected into the fuel mixture. If it gets in the carb bowl, then the mixture goes to 100% water and the engine dies.
steam clean the inside of the combustion chamber. GM used water as means of knocking excess carbon loose for years. A very slow drizzle is all an engine can tolerate before it stalls. That is because it is mixed with the fuel mixture when it is poured or injected into the fuel mixture. If it gets in the carb bowl, then the mixture goes to 100% water and the engine dies.It doesn't look too good...
Is there any saving this?
I unscrewed the intake, and as you can see, it's quite carboned up.
Can this be fixed? What's the proper way to repair it?
I suppose the cylinder head should come off and the valves need to be lapped?
Which repair kit (gaskets, etc.) do I need for this job?
The AI says the valves on this engine (124T07 0260 h1) can be adjusted (via adjustable rocker arms). I had actually assumed that wasn't so easy with this type and that grinding/lapping was required.
Is there any saving this?
I unscrewed the intake, and as you can see, it's quite carboned up.
Can this be fixed? What's the proper way to repair it?
I suppose the cylinder head should come off and the valves need to be lapped?
Which repair kit (gaskets, etc.) do I need for this job?
The AI says the valves on this engine (124T07 0260 h1) can be adjusted (via adjustable rocker arms). I had actually assumed that wasn't so easy with this type and that grinding/lapping was required.
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First of all you have a flat head engine and the valves can only be adjusted by grinding off material from the end of them. AI is wrong often enough. I would remove the head and clean up all of the carbon. I use WD40 and a Dremel tool with a wire wheel. There are a lot of ways to do it. WD40 is a solvent and light lubricant and tends to soften the carbon and as a lub it prevents. scratching the aluminum too much. Using your model number look up the part numbers for the gaskets you need. Go to Jacks or some other on line supplier of Briggs parts. You may be able to reuse some of them if they come off cleanly. If you are careful and lucky. Inspect the valve lash using feeler gauge when the engine is at TDC. I think the clearance should be .005-.007 for the intake and .007-.009 for the exhaust. No need to assume when you can measure and know. There are on line videos on how to do this. If it is getting to be too difficult for you, then take it to a small engine mechanic. You do not want to screw this up.
sgkent
Lawn Addict
this thread is three pages and too much to do to read them all again so I'll just answer. Have you done a compression test with the engine cold, and another with it hot? if the valves are too tight to where heat is opening them, the pressure will drop significantly with the engine hot.