Outdoor Power Equipment and Small Engines - Bs V2 Engine Does Not Turn Over Easy

Hi , I'm haven some concerns on want to do about this stubborn engine. The Briggs motor is on a 2000 Yardman 604 tractor. It's a Briggs and Stratton model 407700 vertical crankshaft ohv 2 cylinder.
I had some trouble with it running on one cylinder 2 years ago . I discovered that the valve push rod on the number 2 come out of the rocker cause the rocker nut was loose. Thighten it up and it started . I mowed all last summer with it. But the battery has to freshly charged and you have to hand turn the motor fan to crank the engine over tdc so the starter can turn it over to get it going. If you don't the starter will not turn over tdc by itself. Or I use to have to turn the key start on and off hope the motor would turn it over. I thought it might be the starter so I took it apart and greased the shaft bearings. That helped but it back again in the fall last year.
Anybody having or had this Problem with this engine ? What did you do to correct it. Thanks

If your are sure that the battery is up to par,all the terminals are tight and the wires doesn't have any breaks in them and there is nothing wrong with the starter moter,then check the valves again.Over Head Valves are Notorious
for slipping out of adjustment.They should both be set at 0.004.Check the push rods too.

If you don't know how to set over head valves I've got a manual in PDF on one of my websites @

http://esnips.com/web/TECUMSEHREPAIRMANUALS you'll need a win zip also

TIP
It is recomended to check the valeves on an OHV engine once a year,more often if the mower/tractor is used for commercial use.

GOOD LUCK,let us know how it turns out

I will check the clearence. I not sure if I did that , I think I did but not going to hurt to do it this season.

Well I can tell you that a slow cranking starter can be a sign the starter is on the way out the door, For a week or more I was haveing the same problem then today I went to start the mower and nothing !! Had to repace the starter good news is if you can get the flywheel off their not hard to change.


Crom

I have had several of these engines with the same problem. Most were out of adjustment on the valve lash which mostly runs in the .004 to .007 range. Also take the plugs out and watch the rocker arms as you turn it over slowly for the compression release, which is on the intake valve on some of these engines. Have replace cam shafts on atleast two engines since last summer that were not working properly. Make sure you are adjusting the lash at the proper position of the pistion. These engines are about a quarter inch drop in the piston after top dead center. This will take the cam past the compression release. I hate to tell you this but one of the cam shafts that I had replaced had an intermittent compression release. It would work by turning over by hand with the sparkplugs out but when I spun it with the starter motor the release would drop out too early due to a weak spring. A new cam fixed the problem.

This is a twin cylinder Briggs Intek and it does not have a MCR (mechanical compression release) mechanism on the camshaft. You will set the valve clearances with the corresponding piston at TDC (top dead center). Briggs calls for .005" clearance on both the intake and exhaust valves.