adjustinig valves on B & S 18.5 OHV engine? difficulty

[hankzudd]

anyone done it? mower is about 4 years old, no idea of hours.

shop estimated around $60, so I'll probably let them do it, but i'd still like
to know how hard this is.

I don't do internal engine work on my cars, so maybe it's better for the shop to do this job. thanks

 

[SeniorCitizen]

anyone done it? mower is about 4 years old, no idea of hours.

shop estimated around $60, so I'll probably let them do it, but i'd still like
to know how hard this is.

I don't do internal engine work on my cars, so maybe it's better for the shop to do this job. thanks

You'll never learn any younger. All it amounts to is rotating the engine until the piston is going down on the power stroke and inserting the correct feeler gauge thickness between the rocker levers and valve stems where the green boxes are in the pic. When the feeler is beginning to drag stop adjusting the nut in the center of the rocker and lock it. Then re-check after locking. Need help if it seems intimidating? Just ask. Tools needed are minimal.

 

[hankzudd]

thanks; this & some youutube vids makes it easier to understand; what's the clearance on each
valve? thanks

 

[SeniorCitizen]

thanks; this & some youutube vids makes it easier to understand; what's the clearance on each
valve? thanks

You'll find a clearance specification chart here to be very handy plus more information

Valve Clearance | Briggs & Stratton.

Here is some information from Briggs :

Adjusting Overhead Valves

Release the brake spring. Then, turn the flywheel to close both valves.

Insert a narrow screwdriver into the spark plug hole and touch the piston. Turn the flywheel clockwise past top dead center until the piston has moved down 1/4". Use the screwdriver to gauge the piston's range of motion (image F)
. PLEASE NOTE: This procedure must be performed for each cylinder on V-Twin engines.

Check the valve clearance by placing a feeler gauge between the valve head and the rocker arm (image G)
. Clearances differ for the two valves and typically range from .002 - .004" to .005 - .007". Valve clearance specifications for your engine series are available by viewing our Engine Specifications Chart (PDF).

Adjust the clearances as required by turning the rocker screw. Once adjustments are completed, tighten the rocker nut.

Install the valve cover, using new gaskets, as required, and make sure the cover is secure.



There is one thing in this information I strongly discourage and that is putting a screwdriver into the spark plug hole to monitor piston travel. A drink straw will do just as well while avoiding any chance of piston, cylinder or spark plug hole damage.

Also, the 1/4" past top dead center ( TDC ) on compression stroke and into the power stroke isn't that critical. 3/8" , 1/2" or 1" will work just fine.

New valve cover gasket ? Unless it tears or breaks try it without buying new. If it leaks it isn't the end of the world and you can then buy one. And those little valve cover cap screws need inch lbs. of torque.

 

[hankzudd]

you guys are great; thanks & I'll let you know how it goes tomorrow.

 

[hankzudd]

got it running again; thanks SR; now how do I check & make sure my charging system is putting out
the correct voltage? Do I just check across the battery with a meter?

also, is there any trick to replacing the clutch cable (to the cutter engagement); thanks in advance.

 

[ILENGINE]

Just check across the battery with a meter. Should be in the area of 13-13.5 volts, maybe up to about 14 depending on charging system.

The engagement cable is a finger skinner no matter what you do.

 

[motoman]

Instructions on this task understate the technique required. Patience is required. You may feel like a one armed paper hanger. The rockers will wobble some because of design. The feel of a slightly dragging (correct)feeler gauge is an acquired skill. Often when the desired drag is felt you lose it in the final tightening of the lock nut and must redo it. The locking torque of the nut is quite light. Why do I say this ?

Not to deter but to motivate you to be easy on your self until you acquire the skill. I also find squatting beside the heads of my V Intek to be tiring. Bring the tractor engine up to a better level. I also second that you may be able to reuse the valve cover gasket if careful. :thumbsup: