Timing a Tecumseh 7hp without a dial gauge?

#1
I need to replace the points and condenser on my HH70 Tecumseh due to a no-spark situation. The manual says I can set the points "by rotating the crankshaft until the point arm is resting on the high side of the ignition cam."

My problem is I can't really tell where the highest point in the cam lobe is. There are no markings on the cam lobe. I'm worried that I'll set the point gap off if I just eyeball where the high point is. I can tell pretty well where the high side of the cam lobe is....but I'm just assuming and also I'm not sure if the piston should be all the way at the top of the pistons travel (TDC) with both valves closed to set the gap? But I also hear many Tecumsehs use "advanced" timing..so that could tell me the piston could be past TDC (right?) to set the point gap.

I can't get a straight answer online, the two I get are 1) "sure just set the points at the high point of the lobe." or 2) "Just use a dial gauge or your timing is going to be off.". I was told using a dial gauge is really only necessary when adjusting the armature assemblys' position. I'm hoping I don't have to buy one just to set the points on one engine. I wish somebody on here had a side business of rent out the dial gauges out with a deposit in case the person decides to keep it. (hmmmm.......)


Here is the manual I'm using: http://ww2.justanswer.com/uploads/giftindex/2012-05-16_104037_692509.pdf
 
#2
The Tecumseh Manual leaves a lot to be desired when it comes to timing. 1) if you're going to replace points, you'll see the cam. Once you remove the existing points, you should be able to slide the cam off the crank. If you eyeball it, you'll see the high spot. Make sure you slide the cam back on the same way you took it off. 2) See: https://www.oldminibikes.com/forum/tecumseh/140821-project-14-854-block-rebuild-4.html for tips on setting the points (post 32). You set by eyeballing the high point on the cam. You don't need to be at any particular TDC to set point gap--just the high point of the cam, any stroke. 3) You are going to have to reset the timing. New points means timing adjustment. Some folks just lock the assembly down at or near the imprint of set bolts: it might run, it might not. 4) Tecumsehs are notoriously finicky. You really need to be at TDC, compression stroke, both valves closed when you set the timing (why? beats me, but this way gets me there quicker).
5) see: https://www.oldminibikes.com/forum/...-solution-dial-indicator-mount-poor-mans.html A dial indicator is 15 bucks at Harbor Freight. A couple bucks at the hardware store and you are good to go. I use it for a lot of measurements (endplay being one). 6) a OHM meter is another must--3.99 at HF or Lowes.

Timing a TEC takes time and is frustrating. Be patient. Finally, look for a Tecumseh H60 timing video on YouTube (not the factory V60 video), follow along and watch 3-4 times.

There are a couple of us who bang our heads frequently with TEC points. Other guys may post other tips and tricks. PM if you're stuck.
 
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#6
Because .020 gap at TDC is not always practical to get the .080/.090 (On an H70) on the advance. Sometimes you have to set them at .017 or so to even get them in there for continuity at advance.

IE, installing points at TDC and .020 might not be where the magneto plate is tacked down at.

The even bigger reason is that replacement points from China are so damn finicky that the tensions are all wrong right out of the box. I throw about 1/3 of the replacement points I get in the trash. Point contact alignment is off, spring arm tension is wrong.

I'm not one of the OldMiniBikes guessers, (grin) I found this by actually going through the timing procedures, and realizing the damn points I was using would NEVER yield a timed engine.

On the other hand, we could tell the guy, and rightly so, to just keep the stator plate where it's at, and gap the points to .020 at TDC. Only problem with that, is that he would have no guarantee it was timed correctly (my comments above) but he's already retorqued the flywheel, ran the fuel line and magneto wires/plug wire, torqued on shroud/head, and has it all buttoned up, only to find that it (1) wont start, (2) starts and idles great, but wont accelerate, or (3) backfires and shears the flywheel key. Granted, there is (4) it runs great.

Of course, guy like me, I go through the timing sequence, button it all up and it still wont run. :laugh: Why? Because the BRAND NEW points were intermittently fluttering. Never saw that on the ohm meter, and only duplicated dynamically.

Sorry Mark, LOL, you asked. :laugh:
 
#8
Thank you for the detailed reply, it actually explains a lot. I don't use knockoff parts, never have. That cures a lot of headaches right off the bat:thumbsup:
Yes. On my last timing battle, and on try #3, I tossed the points in the trash and dug out an old set of Tecumseh points, cleaned them up and the difference was immediately noticeable.

As far as the original poster, we can detail in a response how to time these engines, for the umpteenth time. But it's all in the book, and until you get the depth gauge, the fixture to measure piston drop, and an ohm meter, it's just a crap shoot. You really need to get the required tools, and play with it, with the book in front of you, and it will start to make sense. Otherwise, it's just a 500 word essay on a mini bike forum, where our eyes glaze over after the second sentence. (Like reading the Tecumseh manual in the first place)

I just read that the average American has an attention span of 8 seconds, right behind gold fish. Not trying to be offensive here. Timing a Tecumseh Tediousness has probably accounted for more Harbor Freight business with Predator Purchases than anything else. (grin) My attempt at Poetic Alliteration.
 
#9
Thanks for the replies. I just made sure I had placed all the coil and condenser connections in the right place. The IS spark, just enough to feel in my hand though.
Coil is new.
Points are new they are cheap Chinese points presumably, OREGON brand from eBay. So is the coil. Still have the OEM coil. Wish I had bought Tecumseh points for sure...but I have used OREGON stuff when I had a landscaping biz...and it always was reliable stuff it seemed.
First I gaped the points air gap at .20 with feeler gauge as specified to the best of my ability.. I made sure it was at the highest point on the timing lobe, valves were closed and piston up. I didn't screw with the armature bolts at all. The armature is in the stock position.
Long wire from coil and condenser lead to the points post. Onto that a small lock washer and a nut tightened good. This nut and washer holds down the condenser and long coil leads onto the the points post.
Short wire from coil grounds near coil onto the armature body and goes underneath the condenser when it screws in.
I had to replace the screw which holds the condenser and the small lead from the coil because the head was rusted/stripped, making the connection questionable. A generic #10 machine screw fit. And fits nicely.
I cleaned the grounding contact point where it screw down with some sandpaper and aerosol electrical contact cleaner.
Checked the crimped on plug wire end/preyed it apart and cut off some fresh wire and made sure it was piercing into the plug wire nicely, it was/is and I am nearly positive of that.
I don't think any wires are rubbing. from the way the are routed behind the metal shield and out of the path of the flywheel.

I'm hearing a million different things about setting the points on these engines it seems. The first is that you only need a dial indicator to set the armature assembly gap. The next is that you just have to make sure the points are on the high point of the lobe, which if you read the manual, it says to set the points first before doing anything with the dial indicator at all. The dial indicator procedures, from the wording of the manual the armature setting comes after setting the points.

There is only enough spark to feel in my hand when spinning with the flywheel..so there IS spark I guess. The spark is very weak like I said.

I haven't torqued the flywheel all the way down though here since I've gotten the weak spark (only about 1/4 way down), and maybe I should...well I know I should to run the engine of course. It's honestly just that I really hate to have to repeatedly pry it off again and again if the spark is weak/non existent like it has been. Would torquing it down to spec (52.5ftlbs) significantly improve the amount of spark I receive? The last time I set a Tecumseh it was h25 type engine and it seemed to get great spark by just placing new points/cond. in it and setting the spark gap on the high point of lobe, then when I would put the flywheel on it and didn't torque it down all the way it would still get spark, but the timing would be crazy off till I torqued it all the way down.
 
#11
Sooooo....
The big question for you now is are you going to spring for the $ 11.00 and get the proper tool and do it right?
Michael
Sure, no prob, do I have to get the $30 dollar stand to go with it?

How does having this gauge help me set my points?

EDIT: I see now: "IE, installing points at TDC and .020 might not be where the magneto plate is tacked down at."

I see no reason why the magneto assembly would be moved from the stock position. This engine wasn't maintained much and I doubt anyone has been under the flywheel ever. Should it not work in the stock place? But it COULD be out of the position. I sincerely doubt it. But until I get a gauge setup, I suppose I won't know.

And setting the points from my best understanding is a different procedure altogether from changing the actual armature adjustment. Which I have not dinked with. Everything I have read has leaned towards them being two different procedures. The factory Tecumseh instructional video I watched earlier in fact said you should replace the points before moving onto the armature position. Please correct me if I am wrong.

[video=youtube;axCzcFI4kek]https://www.youtube.com/watch?v=axCzcFI4kek[/video]

BTW: This is going onto a Tote Gote. Due to its Americana status, and the fact nothing else will fit, this Tecumseh is basically the only thing I would ever think of using on it. Clones have their place but not on this bike.
 
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#12
Hey, that is an excellent video. I time them the same way. (as do most of us with running engines) :) The rest of what I was saying concerning the stator plate has to do with wear, and the guy who was working on your engine before you were.

If you are 100% sure that no one moved the plate, and that when it was timed before, the points were installed at exactly .020, and that his .020 was at exactly the same place on the points cam as yours, and that your .020 "feel" is exactly like his is, then it will 100% run correctly.

If you are not sure of those things, and don't want to untorque the head, pull the flywheel again, etc. etc. and want to be sure you timed it correctly, go ahead and do it right.

After all, you have plus or minus .005" of piston travel to play with. In Tecumseh terms, that is less movement than you will get when tightening down the stator plate, and .003" different with the feeler gauge that doesn't fit in there so well.

That is why it's so tedious. Not hard, but tedious. How many times do you want to take apart your engine? Is it worth taking the chance and just slapping in the points? Up to you. That was a great video. I learned something from it: putting the termimal nut back on the points when measuring the ohms, to get correct points tang tension. That makes sense, and it probably why I was having issues with Chinese points. So thanks for that!

I like Gotes, still have one, and I appreciate anyone who determines using a vintage engine is preferable to a Fricking Predator. :laugh:
 
#13
Hey, that is an excellent video. I time them the same way. (as do most of us with running engines) :) The rest of what I was saying concerning the stator plate has to do with wear, and the guy who was working on your engine before you were.

If you are 100% sure that no one moved the plate, and that when it was timed before, the points were installed at exactly .020, and that his .020 was at exactly the same place on the points cam as yours, and that your .020 "feel" is exactly like his is, then it will 100% run correctly.

If you are not sure of those things, and don't want to untorque the head, pull the flywheel again, etc. etc. and want to be sure you timed it correctly, go ahead and do it right.

After all, you have plus or minus .005" of piston travel to play with. In Tecumseh terms, that is less movement than you will get when tightening down the stator plate, and .003" different with the feeler gauge that doesn't fit in there so well.

That is why it's so tedious. Not hard, but tedious. How many times do you want to take apart your engine? Is it worth taking the chance and just slapping in the points? Up to you. That was a great video. I learned something from it: putting the termimal nut back on the points when measuring the ohms, to get correct points tang tension. That makes sense, and it probably why I was having issues with Chinese points. So thanks for that!

I like Gotes, still have one, and I appreciate anyone who determines using a vintage engine is preferable to a Fricking Predator. :laugh:
That is a good video...however, there's another one with a horizontal that I had used. Literally, i had my laptop sitting next to the engine and stopping/starting video each step of the way.

To answer the OP's question: Yes, points are set independently of the timing and is done first.

To @HavasuDave 's point (and we recently commiserated in our misery privately), even factory Tecumseh points can be crap (they are from Taiwan). The spring tension has to be checked/adjusted or the points will not rest properly on the cam.

IMHO, if you want your engine to have a chance of running well, reset the timing. The new points are going to be thicker changing the position on the cam they open (as Dave explained to MarkG's inquiry). Tecumsehs are not like stock Briggs engines where close does count. The link I posted for the OP has good pics of what it's supposed to look like. I forgot to mention BTDC is achieved by clockwise rotation of the crank...you have to remember because it's opposite facing the flywheel side of the engine.

Yes, a stand is nice, but I was cheap and made mine out of flat stock and drilled some holes. Works fine. I'll get around to buying one one of these days.
 
#15
Ok, this is making more sense now. You can throw the points in and gap them on the high point of the lobe but that isn't to say what they are set against (the armature gap) is accurate.
I'll buy a dial gauge and have no problem with fabbing a small "¬" shaped bracket out of band metal.
It's just that I had conflicting information regarding if it was really a necessary procedure. The lead mechanic at a local outdoor power center, who is a veteran and avid minibiker himself (and has been a huge help). He said that he just sets the points at .20 and then matches up the marks that are (supposed to be) on the armature assembly or "looks for bolt marks where it was originally". And that, I was told, was "adjust the timing" and that it "wasn't necessary to mess with the armature if you're just doing the points/condenser, provided you didn't mess with the armature assy."(I didn't). But I guess the real OG professional way is to go through the dial gauge procedure to ensure it is ACCURATELY TIMED. It may not be just throwing in and gaping the points. Obviously something is amiss on my motor because everything is hooked where it can only go and still gets weak spark LOL. I'll try to remember to update this when I get spark/my next issue.

Thank you!
 
#16
^^^We are glad to help^^^ Like I said earlier, some folks do it the way you describe and hope for the best. It, by the way, is not unusual to have what appears to be a weak spark if rotating by hand. Once you have it back together and the recoil on, I suspect holding the wire and giving the recoil a yank will more than tingle your hand (you might not like it much). Just be patient, it probably won't all work first try at setting timing. That's 1/2 the fun with these engines!
 
#17
Listen too and follow the CORRECT advice you are receiving from the OldMiniBikes members here and you will be able to educate your "...lead mechanic at a local power center" about the importance and need of using a dial gauge to set the timing on a Tecumseh! LOL
Michael
 

MB165

Active Member
#20
no biggie.....set the point gap first.
theres many ways to get it done, you could pull the head flip it over and spin it around 180 degrees. use two bolts to put it back on. use feeler gauges stacked on the piston to zero gap at tdc, then add the appropriate amount to the stack and come up till it hits. set timing with a continuity tester or rigged up flashlight
on some there were serrations cut into the stator plate from the washers, but if its been apart a few times who know where it really is. take one bolt out and look, if its a never been apart it doesn't necessarily need reset.
airgap is not settable, the stator centers off a pilot on the block.
 
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