Setting a Tecumseh HS 40's Timing???
I do it with a dial indicator on the piston with the head off. I set points to .020. With the dial indicator I spot the piston acording to specs. I think about .065 but not sure. Unhook the wiring for the condenser and kill switch from the points. I use a continuity light or meter from the points teminal to ground. Rotate the point and coil assembly against the direction of crankshft rotation, just as the points open the light goes out or the meter reads resistance. That is the sweet spot. Tighten the coil and point asembly. Back up the crank and then turn it back in the direction of travel, watch the dial indicator and just as it comes into the spec range the light goes out if not fuss with it some more.
What George said. I'm not kidding.....if you don't get it right, it will never run right and will end up being a major headache to do over and over. IE:....take the shroud off, take the head off, take the flywheel off, blah, blah, blah etc, etc.
You will be farther ahead to just take it to a guy that can get it right the first time.
You will be farther ahead to just take it to a guy that can get it right the first time.
This thread was the info I used to adjust timing on one of my HS40's. Using the stated .065 with the tec dial indicator and offset foot didn't work. A carb rebuild, hard starting, and partially sheared key later, I look at the service manual and see the spec is .035 btdc.
So....am I out to lunch here? Numerous "web" references to .065.
So....am I out to lunch here? Numerous "web" references to .065.
Thank you for that information. I am using an "online" version of a 1998 Tec manual that outlines several models. Towards the end of the book, it lists HS40 at .035, with the H35 (1982 and prior) at .065.
No year MFG differences are stated for the HS40.
Note, my HS40 is model 55232A Serial Number 3276. It is stamped onto a plate that is riveted on the shroud in the usual place. I can only guess if it was an 83 or 93 engine. Doubt it was a 73, since the shroud looks like the 80's engine sitting next to it.
Scratching my head on this one.
Symptoms were bad carb, so I rebuilt. (It WAS clogged) At the same time, I replaced points, condensor and plug. Checked magnets, then adjusted for TDC with the dial gauge. Plug gets wet, good, strong spark, bit of kickback, and now a partially sheared key. That's why I assumed I timed it wrong.
No year MFG differences are stated for the HS40.
Note, my HS40 is model 55232A Serial Number 3276. It is stamped onto a plate that is riveted on the shroud in the usual place. I can only guess if it was an 83 or 93 engine. Doubt it was a 73, since the shroud looks like the 80's engine sitting next to it.
Scratching my head on this one.
Symptoms were bad carb, so I rebuilt. (It WAS clogged) At the same time, I replaced points, condensor and plug. Checked magnets, then adjusted for TDC with the dial gauge. Plug gets wet, good, strong spark, bit of kickback, and now a partially sheared key. That's why I assumed I timed it wrong.
I was just guessing that having it ignite a few degrees out would cause a kickback- at least I feel it in the starter rope. I'm no expert, I am just another minibike guy trying to get an old motor running. 
The difference between published timing settings has got me wondering though.
Edit: Just timed it again to .065. Noticed points were dicked up, readjusted, no backfire on the rope, no start, a bit of white smoke. New flywheel key sheared.
Adjusted to .035, (after fabricating new key) and got it running. My carb rebuild obviously sucks, but at least I got my answer. .035 btdc at least on the HS40 sitting in my garage. Guess I'm outta this thread- thanks for letting me add and ask and for the answers. Obviously, there are some issues with the book.
The difference between published timing settings has got me wondering though.
Edit: Just timed it again to .065. Noticed points were dicked up, readjusted, no backfire on the rope, no start, a bit of white smoke. New flywheel key sheared.
Adjusted to .035, (after fabricating new key) and got it running. My carb rebuild obviously sucks, but at least I got my answer. .035 btdc at least on the HS40 sitting in my garage. Guess I'm outta this thread- thanks for letting me add and ask and for the answers. Obviously, there are some issues with the book.
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