I got a 97 or 98 mtd for 30$ motor was said to run and tranny case was cracked..ditched the vari drive and made it into a mudder with a dofferent tranny. Well the motor doesnt run for me..the 3 strokes turn fine but as soon as it gets to the compression stroke it is so hard to turn over, even a truck battery wont do it. I dont know what the problem seems to be..i looked at the valves they seem fine. Its a 97or 98 briggs 14.5 hp ohv the model number is 287707 and i have the manual for it. Anyone got any ideas what it is? Thanks
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Age : 51 Join date : 2013-04-21 Points : 7244 Posts : 2914 Location : Ontario Canada
If you look in our engines section, you will find links for service manuals. Download yours for specific instructions on checking and setting valve lash.
It's possible that the valves have been adjusted wrong. It's common practice to adjust valves with the engine at TDC (top dead center), but on these (and most other OPE) engines the engine needs to be 1/4 past TDC. This allows the built-in decompression to work properly after valves are adjusted.
I did this the wrong way once; I couldn't get the motor to crank over even with a truck battery jumping it. Readjusted the valves at 1/4 past TDC and it cranked over fine with just the mower battery.
The Briggs & Stratton website mentions this for valve adjustment.
Lawren Wimberly Established Member
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Age : 57 Join date : 2013-12-21 Points : 4731 Posts : 744 Location : Salem Illinois
It's possible that the valves have been adjusted wrong. It's common practice to adjust valves with the engine at TDC (top dead center), but on these (and most other OPE) engines the engine needs to be 1/4 past TDC. This allows the built-in decompression to work properly after valves are adjusted.
I did this the wrong way once; I couldn't get the motor to crank over even with a truck battery jumping it. Readjusted the valves at 1/4 past TDC and it cranked over fine with just the mower battery.
The Briggs & Stratton website mentions this for valve adjustment.
I agree definitively. This is the most common prob with an OHV. They will need to be adjusted just about yearly. Dunno why they go out of adjustment, just know they do.
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Age : 51 Join date : 2013-04-21 Points : 7244 Posts : 2914 Location : Ontario Canada
As for the adjustment... Wear. Cam wear, lifter wear, rod wear, etc etc etc. Normally, these things would go completely unnoticed, if not for the very obvious effect with the compression relief.
unscrupulous mechanics will often tell you they had to replace this or that, and charge you a lot of money, when all they did was adjust the valves... 15 ninute job. I caught someone locally pullin that crap on the old ladies next door... I demanded the old part... He brought out a part FOR A COMPLETELY DIFFERENT ENGINE! (the governer for a flathead) I busted his chops, called the owner in, got the man fired (this was a reputable place, the guy was skimming the extra)
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the54 Member
Age : 30 Join date : 2014-01-12 Points : 3952 Posts : 51 Location : Ontario Canada
It's possible that the valves have been adjusted wrong. It's common practice to adjust valves with the engine at TDC (top dead center), but on these (and most other OPE) engines the engine needs to be 1/4 past TDC. This allows the built-in decompression to work properly after valves are adjusted.
I did this the wrong way once; I couldn't get the motor to crank over even with a truck battery jumping it. Readjusted the valves at 1/4 past TDC and it cranked over fine with just the mower battery.
The Briggs & Stratton website mentions this for valve adjustment.
Buy 1/4 past TDC I hope your referring to 1/4 INCH past TDC. Not a quarter rotation. The book calls for 1/4 inch past TDC.
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Age : 51 Join date : 2013-04-21 Points : 7244 Posts : 2914 Location : Ontario Canada
if i was you i would pull the intake off remove the valve inspection plates turn the engine over by hand and make sure all the valves move if one dosent i suspect the cam might have a broken lobe