I received a pile of equipment from a friend a couple of weeks ago and pulled a 2HP B&S off of an edger. I have replaced the cast iron flywheel, mag, points and condenser with a flywheel and magnetron from a later model vertical shaft mower engine.
I have a two stroke dual needle carburetor I intend to use with a homemade manifold.
Well, I had a mower with a ~3.5HP engine (10A902 2286 B1 01092554) that had about another 1/2" of stroke. Being the tinkerer that I am I striped both engines down and started comparing parts.
The 3.5HP crank has the same main bearing journal diameters as the 2HP. The 3.5HP rod is sorter than the 2HP rod by just the right amount to net nearly 0 deck height (sunken maybe just 1/16". I will need to fabricate a dipper for the rod, as it has the angled spit on the big end.
The plastic 3.5 cam is a perfect fit with slightly more lift and no easy spin start lobe. I removed the centrifugal compression release before this idea came to fruition, wish I had left it on now.
The 3.5HP cam followers are slightly longer than the 2HP followers, so I may grind the backsides of the lobes for a smaller base circle, and grind the longer followers to fit, netting more lift.
The exhaust port is not machined for bolts or a gasket, just a pipe thread. For the exhaust I was thinking a shower head pipe with a 45* bed and as much length as I can find for a header.
"Stroker" crank with the stock 2HP crank in the foreground.
Higher lift plastic 3.5HP cam with stock 2HP in the fore ground.
3.5HP rod and 2HP piston assembled.
There is no obvious mark indicating the flywheel side of the piston, only these two marks on the pin bosses. If no one here knows, I suppose it probably wont matter too much.
I have a two stroke dual needle carburetor I intend to use with a homemade manifold.
Well, I had a mower with a ~3.5HP engine (10A902 2286 B1 01092554) that had about another 1/2" of stroke. Being the tinkerer that I am I striped both engines down and started comparing parts.
The 3.5HP crank has the same main bearing journal diameters as the 2HP. The 3.5HP rod is sorter than the 2HP rod by just the right amount to net nearly 0 deck height (sunken maybe just 1/16". I will need to fabricate a dipper for the rod, as it has the angled spit on the big end.
The plastic 3.5 cam is a perfect fit with slightly more lift and no easy spin start lobe. I removed the centrifugal compression release before this idea came to fruition, wish I had left it on now.
The 3.5HP cam followers are slightly longer than the 2HP followers, so I may grind the backsides of the lobes for a smaller base circle, and grind the longer followers to fit, netting more lift.
The exhaust port is not machined for bolts or a gasket, just a pipe thread. For the exhaust I was thinking a shower head pipe with a 45* bed and as much length as I can find for a header.
"Stroker" crank with the stock 2HP crank in the foreground.
Higher lift plastic 3.5HP cam with stock 2HP in the fore ground.
3.5HP rod and 2HP piston assembled.
There is no obvious mark indicating the flywheel side of the piston, only these two marks on the pin bosses. If no one here knows, I suppose it probably wont matter too much.
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