I have been getting my butt kicked by this lawn tractor all season and push mowing my lawn in the mean time.

MTD 42" "Shift on the go"
Briggs 14.5 HP

When I go to start it, it seems to crank strong and solid until it hits the compression stroke. While the started is still engaged, I can turn it past this "sticky spot" and it will rotate again to the compression stroke.

If I take out the plug, it will spin all day long.

This is done while jumped from my car. I have also jumped the starter straight from the hot post on the starter. same result.

Thinking it might just be a weak starter, i dissasembled and cleaned it, put it back on an I get the same result.

I'd love to hear any thoeries...

Regards,
Dave.

What is the model number of your engine?

Sounds like your compression release is not working, may be a simple valve adjustment or could be the compression release mechanism on the camshaft.

Thanks for the response...

Model: 287787
Type: 1224-E1

I would check the valve lash on your engine, I believe it should by .003-.005" on the intake and .005-.007" on the exhaust. If you have too much clearance on the valves, your compression release will not activate the valve and the compression will be too great for your starter to overcome.

Is this an external adjustment? The furthest that I have had one of these apart is to remove the flywheel...

The valve adjustment is made by removing the valve cover (four bolts). The adjusters are on the rocker arms that operate the valve. You will need a set of feeler gauges in order to set the clearances properly.

Alright, I found some time to tear this thing apart. I wanted to make sure that I understood what the valve lash was. I took the valve cover off and depending on the position of the piston, the rockers are "sloppy" leaving a gap between the top of the valve and the rocker. Is this what I want to set to ".003-.005" on the intake and .005-.007" on the exhaust."

Q: To I turn the nut in the center of the rocker to adjust?
Q: How do I tell which is the intake and the exhaust?

rocker with card stuck in the "gap" in question.
http://farm4.static.flickr.com/3053/2693611755_63cecec99d.jpg

The intake valve is the one inline with the intake manifold from the carburetor and the exhaust is the one inline with the exhaust pipe going to the muffler, looking at the picture you posted, the intake is on top and exhaust is on bottom.

To set the lash, bring the piston up aproximatley 1/4" past TDC on the compression stroke. To find TDC remove the spark plug then slowly rotate the flywheel clockwise (while looking down on the flywheel) and observe the valve operation. After the intake valve closes the piston will start it's upward travel, this is the compression stroke. Place a screw driver or some kind of probe into the spark plug hole until it rests on top of the piston, continue to rotate the flywheel while holding on to the probe in the plug hole. As soon as the probe stops raising out of the spark plug hole and just starts to go back in about a 1/4" STOP this is the position to use for setting the valve lash.

There is a small set screw in the middle of rocker arm nut (may be an Allen head or Torx head screw) loosen the rocker arm nut and then loosen the set screw. Tighten or loosen the rocker arm nut to achieve proper valve lash and then while holding the rocker arm nut, tighten the set screw to lock the adjustment.

Good Luck... :thumbsup:

Thanks. I probably wont get to it until tomorrow.

Another related question though. When I tinkering, I took the nut off of the rocker and the push rod dropped out of position. When I pushed in back in, it felt like it wasnt seated right. so I wiggled it around ant got it back to where it felt right and put it back together. Is there anything that the rod is suppose to seat into on the other side? Just want to make sure I'm not going to blow it apart when (if) I start it again.

Thanks.

Yes, the bottom of the push rod need to set in the little cupped area of the lifter. You may need to shine a light down in the area to see it, if the valve does not operate when you rotate the flywheel, then the push rod is not installed correctly.

and if you try and start it not in the right place, you are likely to break the push rod

Thanks all. I did go back out there last night and checked real close with a flashlight. It looks like it has to be right.

I found a video on youtube that demonstrates how to set the lash on a similar OHV briggs and that gave the kick to go get it done.
http://www.youtube.com/watch?v=hGkn0jR9RJM&feature=related

After I got things set, I turned the engine by hand a few times and it still feels about the same. It's nice and smooth until it compresses and then its real tought to get past the compresssion. I turned it until I pinched my finger between the flywheel and the magneto and then spent some time cleaning up the blood.

The real test will be to roll it out into the diveway and try to turn it over with the starter. Perhaps after work...

Rock on! I pushed it out to the driveway and we are back in business... Sort of. See my next post on the electrical issue.