BriggsReplacement

A Briggs&Stratton Replacement for the Kohler CV15S on the Craftsman Riding Mower

• The CV15S is damaged beyond repair, with scored cylinders
  • Likely initial problem was a failed valve cover gasket, then it ran out of oil
  • The oil dipstick is very difficult to read since oil splashes up the filler tube

    • does anyone make a twin filler tube, reading stick down one channel, fill down the other? How about a CLEAR one?

  • No onsite repair available, we need a towing service to trailer the riding mower to and from repair, spendy!

• Kohler's replacement engine lineup is thin and poorly described.

More Details

• I made a rubbing/tracing of the holes in the chassis. With a bit of care, more holes can be drilled. The pulley through-hole is 7 inches in diameter, so there is room to put in a new engine and displace it from center a bit.

• There's some room between the sides of the hood and the old engine; a newer one can be an inch or two larger. At the top, there is a panel with a cutout for the air inlet; that may get in the way of an oil filler cap, but holes can be cut.

• The frame has a cavity for the old Kohler muffler, and exhaust came out the bottom front. A new engine with a side-mounted muffler will blow exhaust under the hood and some may trickle back to the driver. This will need attention.

Replacing with a Briggs

• Briggs&Stratton FAQ

• Engine Catalog, pages 17 and 18 are 17.5 HP Vertical Shaft

  • 17.5 HP Vertical Shaft

• Best is 31R977-0033-G1 with a 591763 crankshaft. The older, higher price 31R977-0029-G1 has a smaller-diameter-lower-seal 591762 crankshaft.

• I plan to order this direct from Briggs, it is on sale there. Other places may have it 5% cheaper, but my guess is Briggs ships faster, and a direct relationship may help with warranty service later.

• -0033 site search

• parts list . . . operator's manual

• This engine has no superfluous gas pump (gravity feed), an oil pump, and an oil pressure switch.

  • The oil pressure switch is reference number 239 on the lower right corner of the diagram on page 10 and the parts list on page 11 of the parts list.

  • Can an oil gauge be added on a tee from the switch port? A bright LED idiot light in parallel with the oil switch seems good enough.

• How do we wire this particular engine? This is simple wiring, and I have no problem with clipping and splicing wires on the riding mower body, but we may need to buy some mating connectors for the Briggs, not clipping Briggs wires and voiding the warranty.
• I don't have a torque wrench. We will need that to tighten bolts to spec.

• Need more info: The mounting holes on the Briggs may or may not be threaded. 5/16-20 like the Kohler? Still working on this.

Prices for 31R977-033-G1 2018 May 8

More B&S Documents

• wiring diagram page

  • alternator_replacement

  • alternator_specifications

  • ignition_wiring_6_pin_ms5301

  • ignition_wiring_5_pole

• Need more info: what connectors will we need to wire to this? Must we wait for a mail order?

• Engine replacement

  • engine mounting hardware, bolt torque, etc.

Meta-questions

• The Kohler never stalled against a load; is 15 HP more than adequate? A frequent problem is wet grass plugging the lower part of the feed tube to the grass catcher in back. Would more RPM help? Perhaps a supplemental impeller or vacuum draw or conveyor rope loop through the feed tube that keeps wet grass moving uphill.

• Perhaps replace the grass with raised beds and growth-suppressing walkways, and invite neighbors to use the garden space. We don't use the back LAWN for anything. A riding mower is useful for the front and side yards.

Old mower, Kohler information

• Sears Riding Mower 917.271022

  • page 33 shows the wiring diagram, with the battery grounded to the chassis. Both varieties of volt-ammeter from Ebay put the current sensing shunt in the ground lead. So, the battery negative must be run from the battery compartment to the shunt near the meter.
• Old Kohler CV15S / Family SKH426U1G2RB / Spec 41567 / Disp 426cc / SN 2830900233

  • manual

  • service manual