42 in. Deck 19.5hp Lawn Tractor

How to Identify and Fix Common Gardening Problems ?

We provide a variety of viewpoints on how to identify and fix common gardening problems. Our sources include academic articles, blog posts, and personal essays from experienced gardeners :

Clearances differ for the two valves and typically range from . 002 – . 004″ to . 005 – .
Position the dial indicator on the top of the exhaust-valve retainer and zero the dial indicator. Next depress the exhaust valve. Note the distance traveled. Now subtract the difference in the gasket thicknesses and you should have an accurate measurement of the piston-to-valve clearance.
Tappet clearance, also known as valve clearance, is the small gap between the rocker arm and the top of the valve stem (Yoke). Engineers can observe and adjust tappet clearance only when the valves are in a closed position and the engine is cooled at the compression stroke.
A general rule of thumb is that intake guides need guide-to-stem clearance of . 001″ to . 003″ and exhaust guides need from .
Rule of nine

With any given valve open, count what number valve that is from the front. Subtract that number from nine. Whatever number you`re left with is the valve you`re in position to set. So, with number 1 rocker opening its valve, you`ll be setting clearance on (9 minus 1), number 8 valve.

Too much clearance means the valves will likely clatter and, over the long term, cause damage to the valves, camshaft lobes or rocker arms. If there`s too little valve clearance, the valves won`t fully close, causing excessive heat, and the engine will lose power.
Check the clearance between the top rocker arm and the corresponding valve stem, located in the center of the valve spring, using a feeler gauge. If the clearance reading falls outside of the acceptable range of . 005- and . 007-inch, the top exhaust valve is out of adjustment.
Auto shops or mechanics charge around $150-$300 for the adjustment, but it depends on the make and model of your car. The process would involve removing the valve cover and measuring the space between intake and exhaust valves and their lobes with feeler gauges.
To adjust the valve clearance, slacken the locknut with a ring spanner and screw the ball in or out of the rocker a tiny amount, checking the clearance betwixt valve and rocker with feeler gauges. Once it`s correct, tighten the locknut and check again.
Valve Clearance Tips

Recommended valve-to-piston clearance is generally 0.080-inch minimum on the intake side and 0.100-inch minimum for the exhaust valve. The exhaust needs a little more clearance because it expands more with heat.

Check the clearance between the top rocker arm and the corresponding valve stem, located in the center of the valve spring, using a feeler gauge. If the clearance reading falls outside of the acceptable range of . 005- and . 007-inch, the top exhaust valve is out of adjustment.
This is the total volume remaining in the cylinder at the end of the piston stroke. This consists of the volume between the end of the piston and the cylinder head, in the valve ports and the volume in the suction valve guards and the discharge valve seats [26].

Discover Relevant Questions and Answers for Your Specific Issue

the most relevant questions and answers related to your specific issue

Won’t crank over seems like to much compression ?
ANSWER : OHV? First try adjusting the valves too much clearance will the decompressor to not work. Now the decompressor can also fail but try the valve adjustment first.

Hard hitting on compression stroke when starting
ANSWER : If its the 21 or 20 hp OHV single briggs. Adjust vales to .004. The cam also has a decompression that breaks, Causing hard start. So if valves are adjusted and u still have problem. “Could” be cam, remove bottom cover and inspect cam. new cam about 75 to 100 bucks.

Need the valve setting for the intake and ext. on a briggs and stratton motor engine model # 130202-1035-07 serial # 75020607
ANSWER : .005″-.007″ intake

.009″-.011″ exhaust

Set clearance when engine is cold.

My 24hp Briggs and Stratton ohv engine has bent push rods on one side. The top valve can be pushed in but the bottom one will not push in. Is the valve stuck in the open position? If so how can it be fixed?
ANSWER : Unable to answer if valve opened or not but does sound like ur bottom valve is bent or piston made contact and bent it to fix need to remove head and replace valve also need to inspect piston face is not damaged from possible contact

Wshat is the valve clearence for a 24 hp briggs and stratton engine model 446677 type 0470E1 code 050405yh
ANSWER : About a mm or .004″.

Lawn mower will turn over a bit with booster conectd then it doesnt start. Already have a new plug in it.
ANSWER : Adjust the valves to .04 this will do it if you havent damaged starter already, and the battery is good

Valve clearances for jd la valve adjustment only John Deere Tractor Model L A doesn’t cut it with this web site so that is the reason for this approach
ANSWER : 0.08mm-0.13 mm- intake top
0.13mm-0.18mm- exhaust bottom

17 HP Briggs & Str lawn mower engine that is smoking a lot –
ANSWER : Compression test it can either rent or buy one should be over 90psi!!!