Sorry, could not get all the pics in with the first post. Will have to resize and add them later.
Heart Transplant
Well, except for some trim colours and stickers the machine is finally all back together.
This is a 1975 ST12 that had the ignition on the Tecumseh motor finally go the way of the Dodo. Became uneconomical to fix as I had already tried 2 modules with no success. Other than that this mower is damned near indestructable.:i_praying and that 48" deck makes short work of the lawn.
After looking through recyclers and at some of the new junk offered out there finally decided to bolt in a new engine. Could not overlook the cost of one of the knockoff 13HP PowerFist motors so gave it a try. Only problem was the output shaft was slightly smaller, meaning I had to grab two taper-lock pulleys as well, (more on that in a bit).
Surprise! The mounting holes lined up when I was setting up the crank location:bannana: . Same with the original pulley guard/guide for the drive and accesory belts.
As this motor has an integral fuel tank I pulled the stock battery/tank mount and fabbed a .200" U-Shaped plate to fit between the frames. Only bit of fun there was aligning the drive belt clutch pulley and, as I flipped the plate over to give more room between the top of the battery and hood, it took a couple of tries to get the stack height correct for the pedal.
Even though the schematic was a joke it was not that complex to remove the integral control and install the components to the dash. That includes the breaker. Still looking for a 0-5 or 0-10A ammeter as the stock one barely jiggles with the 3A charging system output.
The other pain came from the fact this was an angle-cylinder engine, compared to the straight vertical stock plant. Due to this I used part of the stock battery plate removed earlier to move the front hood mount forward 2". This cleared the motor, but created its own set or problems. Now the tapered hood would not fit and I needed an exhaust deflector to keep the grille and glass from getting cooked.
The deflector ended up coming from a B/S motor and I had to fab a 2" extension bent out of an old industrial shelf.
Final analysis? This motor fit, but required a bit of shoehorning to get it to integrate and line up with the stock drives. I probably made it more difficult by trying to eliminate some of the original complaints of access to certain areas, such as the back of the dashboard and still have a few tweaks to do to the throttle and choke. The former lever range does not match that of the new carb very well and the choke cable does such a severe angle change at the carb there is more friction than I like. On that note, to get the choke cable system I had to shell out close to $55 for the Honda kit. Could not figure any other way to hook up a remote and this motor absolutely requires choke to start. I think a few R/C aircraft linkages will have to get sacrificed to rig it so it will be more reliable and easier to operate.
p.s. Ignore the Ridiculous pic at the end. It's in response to a Father's Day card my son sent me. At least it gave me an excuse to dig out my old Helicopter Flight Gear:sidelaugh .
Oh yeah, that bit about the pulleys? First try had me nearly run it into the neighbors brick wall as I could not get the drive to disengage. The problem ended up being the fact they powder coat the belt shieves along with the outside surfaces! Got nice and sticky and required a bit of work with a hand file and sandpaper to remove. Belts slide nicely now.
This is a 1975 ST12 that had the ignition on the Tecumseh motor finally go the way of the Dodo. Became uneconomical to fix as I had already tried 2 modules with no success. Other than that this mower is damned near indestructable.:i_praying and that 48" deck makes short work of the lawn.
After looking through recyclers and at some of the new junk offered out there finally decided to bolt in a new engine. Could not overlook the cost of one of the knockoff 13HP PowerFist motors so gave it a try. Only problem was the output shaft was slightly smaller, meaning I had to grab two taper-lock pulleys as well, (more on that in a bit).
Surprise! The mounting holes lined up when I was setting up the crank location:bannana: . Same with the original pulley guard/guide for the drive and accesory belts.
As this motor has an integral fuel tank I pulled the stock battery/tank mount and fabbed a .200" U-Shaped plate to fit between the frames. Only bit of fun there was aligning the drive belt clutch pulley and, as I flipped the plate over to give more room between the top of the battery and hood, it took a couple of tries to get the stack height correct for the pedal.
Even though the schematic was a joke it was not that complex to remove the integral control and install the components to the dash. That includes the breaker. Still looking for a 0-5 or 0-10A ammeter as the stock one barely jiggles with the 3A charging system output.
The other pain came from the fact this was an angle-cylinder engine, compared to the straight vertical stock plant. Due to this I used part of the stock battery plate removed earlier to move the front hood mount forward 2". This cleared the motor, but created its own set or problems. Now the tapered hood would not fit and I needed an exhaust deflector to keep the grille and glass from getting cooked.
The deflector ended up coming from a B/S motor and I had to fab a 2" extension bent out of an old industrial shelf.
Final analysis? This motor fit, but required a bit of shoehorning to get it to integrate and line up with the stock drives. I probably made it more difficult by trying to eliminate some of the original complaints of access to certain areas, such as the back of the dashboard and still have a few tweaks to do to the throttle and choke. The former lever range does not match that of the new carb very well and the choke cable does such a severe angle change at the carb there is more friction than I like. On that note, to get the choke cable system I had to shell out close to $55 for the Honda kit. Could not figure any other way to hook up a remote and this motor absolutely requires choke to start. I think a few R/C aircraft linkages will have to get sacrificed to rig it so it will be more reliable and easier to operate.
p.s. Ignore the Ridiculous pic at the end. It's in response to a Father's Day card my son sent me. At least it gave me an excuse to dig out my old Helicopter Flight Gear:sidelaugh .
Oh yeah, that bit about the pulleys? First try had me nearly run it into the neighbors brick wall as I could not get the drive to disengage. The problem ended up being the fact they powder coat the belt shieves along with the outside surfaces! Got nice and sticky and required a bit of work with a hand file and sandpaper to remove. Belts slide nicely now.
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Sorry, got busy and was out of town.
Let's try the pics again. What you can't see in these are the exhaust deflector and the choke cable. Must have added them after these were taken.
Still have to add the stickers.
Let's try the pics again. What you can't see in these are the exhaust deflector and the choke cable. Must have added them after these were taken.
Still have to add the stickers.
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1 - 15 of 15 Posts
