Old engine wont idle

[Garysengine]

Its a briggs and stratton 2 and a half horse. Here is a picture of the throttle linkage with a spring. Wondering if an expert could spot something wrong

 

[Rivets]

Don’t see anything wrong.

 

[slomo]

Don’t see anything wrong.

Put your reading glasses on Rivets LOL. I see a lot.

First off, wash that mud bog Saturday Night Special off. Remove the top metal engine cover. Clean the block and all cooling fins like it was a NEW engine. These are air cooled. Running it like that, you are asking for engine damage. Those fins must be clean and clear to dump off engine heat.

1.Where's your throttle cable? It goes in the green hole.
2.The 2 red areas are just two that are filthy. Clean this engine and blow out/off with compressed air.
3.Blue part is the air vane. The faster the engine revs the more air the flywheel generates to cool the block. Clean this and BE GENTLE WITH THIS PART. Most of these parts are NO LONGER AVAILABLE. CAREFUL with the air vane. The higher revs will push the vane to the left in this pic. Which will close the throttle plate dropping down the revs.
4.Purple is the throttle linkage. Connects the air vane to the throttle plate to control revs.
5.Orange part is the idle speed screw. Set this at 1800rpm, no load.

Far as revs go, Briggs states to run at MAX revs ALL THE TIME. This is for max lubrication and air cooling. This is the recipe for max engine longevity/durability. So set your max revs to 3200-3600rpm. Don't idle down as this is a splash lubed engine. Lubrication will suffer.

Might check the valve clearances while you are there. Clean out the fuel tank and install a new carb diaphragm.

Last time, careful with this little guy. Many parts are no longer made by Briggs. These were built to last.

 

[slomo]

Run SAE 30w oil in that only. Fill to the plastic plug as in overflowing out of the threads. Make sure the block is level doing this.

 

[Rivets]

Don’t know what you see, but he asked about throttle linkage and the way he has it connected he has it connected correctly. Your purple circle is the linkage connecting the air vane to the throttle plate. The spring is connected to the loop in the linkage. Yes, it could use a good cleaning, but the only thing I see possibly missing is an external throttle control.

 

[slomo]

Go clean your cooling fins Rivets LOL.

 

[Hammermechanicman]

Time to clear up, or start a fight, on how the lubrication system works on the old briggs horizontal engines. When engine is started cold the bore, piston, rings, cam, lifters, rod and crank bearings are immediately lubricated with oil quite violently splashed by the dipper attached to the rod bearing cap. Even at low RPMs these components receive adequate lubrication. What is not receiving lubrication is the valves in the valve guides. The oil needs to come up to temperature and be beaten into a mist (not vapor) by the crank dipper. This mist is then carried into the valve spring chamber by crankcase pulses via the crankcase breather. The pulsing mist laden air is forced up the valve guides. As the mist laden air enters the crankcase breather the oil contacts a foam element that causes the oil to to precipitate out of the air and drain back into the crankcase via the hole in the spring chamber. Air that exits the breather is reatively oil free.
Until the engine is up to temp and RPM the to generate the oil mist what will wear is the aluminum block valve guides. Once up to temp idling down the engine will not cause an oiling issue.