Tip on flat head briggs 3.5hp get more hp cheap

[will72rupp1]

I know a lot of you guys are running flat head briggs 3.5hp motor's well if you have one, it has to be the block with two bolts too mount on the coil, this wont work on the older blocks with 4 bolts,

here is a tip for you guys with or with out points,

change over the old steel cast flywheel, too a lighter aluminum flywheel, from a flat head briggs 3.5hp push mower & use the newer solid state coil from the push mower,

the newer solid state coil has just one wire hook up, & it is the kill wire, ground it out & the motor wont start..

If your motor had points leave them in there, & just take out the wire going to the condenser from the old points coil, i just cut them,

make sure you get the flywheel tight & get it all back together & you will notice you freed up some power, the motor will run & start much better

 

[frankthetank]

Pics or it didn't happen. :devil2:

 

[125ccCrazy]

I know a lot of you guys are running flat head briggs 3.5hp motor's well if you have one, it has to be the block with two bolts too mount on the coil, this wont work on the older blocks with 4 bolts,

here is a tip for you guys with or with out points,

change over the old steel cast flywheel, too a lighter aluminum flywheel, from a flat head briggs 3.5hp push mower & use the newer solid state coil from the push mower,

the newer solid state coil has just one wire hook up, & it is the kill wire, ground it out & the motor wont start..

If your motor had points leave them in there, & just take out the wire going to the condenser from the old points coil, i just cut them,

make sure you get the flywheel tight & get it all back together & you will notice you freed up some power, the motor will run & start much better

you have to be careful on what flywheel you get, not all the mower flywheels are clocked the same so it will throw the ign timing way off.... You want one when looking at the flywheel straight on with the magnets at 12 o'clock and the keyway at approx 2 o'clock... Also check them for cracks and sheared keys that booger up the taper, mowers tend to take a beating....

you can also remove the points, the little accuating pin and just silicone the hole shut so there is no worries about an oil leak..

 

[The Restore Kid]

You can also grind a little extra off from the intake valve stem to remove the compression release in the cam.. Makes a huge difference in compression. Make sure to hold the pull handle gently in your fingers and leave a foot or two of rope hanging out of the engine until you know it's running, before you let the rope go.. If the engine stalls and kicks back it will rip the rope out of your hand.. If ya let the rope go THEN the engine stalls, it can tear your rope in half.. :doah:

 

[CC 51]

You can also grind a little extra off from the intake valve stem to remove the compression release in the cam.. Makes a huge difference in compression. Make sure to hold the pull handle gently in your fingers and leave a foot or two of rope hanging out of the engine until you know it's running, before you let the rope go.. If the engine stalls and kicks back it will rip the rope out of your hand.. If ya let the rope go THEN the engine stalls, it can tear your rope in half.. :doah:

.....Voice of experience!!!

 

[mr.modified]

I tried a vertical shaft mower flywheel on a 3.5 horizontal shaft. Definetly makes it tough to start. When you do get it going, it does make it rev a lot quicker. Almost not worth it after the engine kicks back ripping the rope from your hand a few times. Like TRK said, it's hard on the starter. I never tried it with the engine attached to something. I was going to try it on a go kart or something and see if it makes much difference for acceleration.

 

[will72rupp1]

ya you need to bolt on & try it..