Installing Techumseh

[zr1000]

So, I got this 73. It came with 2 engines an "a" and a "b". Neither one has a coil or plug wire,the flywheels are off, the points seem to be there but not sure what might be missing under there. No recoil or gas tank either.

I have a techumseh 2 stroke i'm thinking about installing, it runs and is similar sized with a motor bracket I think i can get to work.

The crankshaft is the same size and the clutch will fit. I will need to move the brake bracket, get a longer chain, and think about trying to reroute the exhaust, it comes directly out the side over the clutch and seemed a bit loud when I test ran the motor.

MY concern is the noise, and the fact that is doesn't have a reduction gear setup. I thought maybe I'd just limit the amount the throttle can be opened, but hope it won't be too fast. My son is not quite 2 and a half.

Any advice? Thanks.

[72]

I have played around with these engines a little. You might want to recheck the size of the PTO shaft, they are usually around 20 or 30 thousands larger than 5/8", may need to be turned down ( or the hillbilly method of droping a file on the shaft while running can also work) . They also have a decompression port/reed valve that can get fouled up and keep the valve from sealing resulting in lossed compression, this can be fixed by taping the port ( I think a 6-32 is the right size)and blocking it with a screw . A thinner head gasket will also help. These engines dont make much power where a standard clutch engages. By drilling two 3/16” holes in each clutch shoe will put the clutch in a better range. If you decide to do this, think about putting in a new clutch spring and have a spare on hand, they are cheap and you will have the clutch apart anyways. If you have a heavier child or use the sled in deeper snow or on hills the spare spring might come in handy. Many of these engines come with a box style muffler exhaust. Some of the toro snow blowers that use this engine have a “header” pipe that dumps into a muffler tube. A little creativity and fabrication could result in an exhaust thats quiet enough and dumps out where you want. These engines are notorious for carbon buildup in the exhaust ports, keep them cleaned out and use a good oil mixed 40:1. These engines twist around 5700-6200, around 8000 is where the rod cap and screws let go.

[zr1000]

72....thanks for the reply. 48 views and finally a reply. LOL.

The clutch does fit, and I will look into the toro header pipe. My little guy is only 2.5 so speed is a definate concern. I hope it has enough power where the clutch engages to get the little sled moving.

The piston size of the motor isn't much bigger, but I peaked in at the piston and it sure looks a lot bigger. Without the reduction, I am concerned about the speed, and I hope to find a way to keep the noise down.

Thanks again for your input. Anyone else, or more to say 72?

[72]

I am assuming you have the 98cc tecumseh engine as they are the most common, but there are other varieties.
It will have enough power to pull out of the hole, it wont move out as quick as a regular kitty engine, due to the lack of gear reduction/clutch engagement, but considering the size of your child it should not be an issue. Top speed could be around double that of a stock kitty (12-14 mph) if the engine is in good condition and the carb is dialed in correctly . If you have the diaphram style carb with the high and low adjustment (bowl style has no adjustments) you could just richen up the high adjustment to control top speed. The low adjustment carries pretty far into the midrange and can affect top end as well. The carb should have a half choke position, this will also limit the top speed. A little trial an error with carb adjustment should get you what your looking for.

[zr1000]

Sounds good, I do have the diaphram style carb. Now I just have to locate a way to route the exhaust, drill a few holes, and find a fuel tank. Thanks again!