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Toro Rototiller Tecumseh H35 Engine Not Starting


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#1 FilledTires OFFLINE  

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Posted January 20, 2015 - 03:39 PM

Hello,

 

I reach out again to my fellow enthusiasts with another project problem I have. This time it is for an old Toro Rototiller with a Tecumseh H35 Engine.

 

I just gave it a full tune up, and internal inspection, and am having trouble starting this engine. I turn to you for something I may be overlooking.

 

This is what I have done:

 

New Ignition Coil

New Spark Plug

New Condenser

Valve Clearances checked

Valves re-lapped

Carbon cleaned off of head and piston

New Carb.

New Fuel Lines

New Head Gasket

 

This what I know:

 

It get's spark, a very hot spark

It has a compression reading of 100

It Gets Fuel

Ground Plug is already unplugged as a bypass

 

I have used starting fluid, and new fuel, but it is not starting. It will spark bright blue when grounded to outside part of engine and ignites starter fluid left on the electrode.

 

What am I missing?

 

Thoughts?

 

I feel I have done all of the proper diagnostic procedures, and in theory there is no reason why this wouldn't start.

 

Help before I go crazy!

 

- FT


Edited by FilledTires, January 20, 2015 - 04:25 PM.

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#2 boyscout862 OFFLINE  

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Posted January 20, 2015 - 03:47 PM

I would look at ignition timing and valve lash. Good Luck, Rick



#3 Bolens 1000 ONLINE  

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Posted January 20, 2015 - 05:33 PM

Sounds like a timing issue/ valve issue

 

Also do you have a spark tester you could put on to see how strong it is under compression. Alot of times you will get a "nice spark" when the plugs out but under compression its a different story.


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#4 FilledTires OFFLINE  

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Posted January 20, 2015 - 06:14 PM

Sounds like a timing issue/ valve issue

 

Also do you have a spark tester you could put on to see how strong it is under compression. Alot of times you will get a "nice spark" when the plugs out but under compression its a different story.

I do have a spark tester and it glows bright orange when I crank it over. The valve lash is correct. I will double check the point gap again to make sure it still is at .020".



#5 New.Canadian.DB.Owner ONLINE  

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Posted January 20, 2015 - 07:06 PM

All engines do 4 things: Suck, Squeeze, Bang, Blow.  If you have compression (squeeze) and spark (bang), then you have a problem with either sucking (intake) or blowing (exhaust).  A plugged exhaust will usually stop a running engine, not stop it from starting.  That leaves you with an air intake problem.  Is your spark plug getting wet or is it staying dry?  If it isn't getting wet after a couple of tries, your engine isn't sucking, or is sucking air from someplace that isn't the carburetor.


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#6 KC9KAS ONLINE  

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Posted January 20, 2015 - 07:21 PM

Did this engine run before you got it, or before you started working with it?

You said, "internal inspection".....Did you have the cam/crank gears apart to get it out of time?


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#7 FilledTires OFFLINE  

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Posted January 20, 2015 - 08:16 PM

Did this engine run before you got it, or before you started working with it?

You said, "internal inspection".....Did you have the cam/crank gears apart to get it out of time?

It did start but did not idle properly. The carb was original and was pretty beat up. I replaced carb, removed head and inspected valve face and seat. I also did a full ignition tune up. After bouncing ideas off of all of you it must be that I messed up the point gap. It's sparking but perhaps at the wrong time? Plug does get wet and doesn't even fire with starting fluid sprayed directly through spark plug hole. In order to do redo the point gap I have to loosen the head, and remove whole flywheel assembly again but I guess that's what I have to do.

 

I did not remove the piston, crank or cam assembly. I guess while I am doing the points I can take the head off and observe when the points open and see where the valves are in that position. In theory the points should open just before tdc.


Edited by FilledTires, January 20, 2015 - 08:17 PM.


#8 superaben OFFLINE  

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Posted January 20, 2015 - 08:26 PM

Frustrating to do all that work and get that, isn't it?

 

I would look towards ignition.  My favorite redneck spark test is to take an old dirty plug and set the gap about 1/8 to 3/16.  If it can fire that gap, you'll be fine under compression.  If it can't fire that gap, I would replace the condenser. 

 

Condensers can do this to you. 

 

Personally, I'm leaning towards a sheared flywheel key.  If will not hit with good spark with ether in the hole, the piston is somewhere other than TDC when the spark happens. 

 

Ben W.


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#9 KC9KAS ONLINE  

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Posted January 20, 2015 - 08:43 PM

I don't know which spray is better or if it makes any difference, but I use carb cleaner instead of starting fluid.

I was told the starting fluid is hard on the cylinder.


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#10 dodge trucker ONLINE  

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Posted January 20, 2015 - 09:09 PM

the magneto can be rotated a ways to adjust static timing. If off far enough it would be like a sheared key.

another possibility   I had an uncle "tune up" a Tecumseh powered push mower once, he put the condenser on upside down and the flywheel wore the condenser wire in two. (but you say you do have spark, I just thought I'd toss it out there)


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#11 superaben OFFLINE  

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Posted January 20, 2015 - 09:10 PM

I just thought, too, that the magneto can be rotated incorrectly, screwing up the timing.  You have to time the magneto right.  I have instructions here somewhere.

 

I don't know which spray is better or if it makes any difference, but I use carb cleaner instead of starting fluid.

I was told the starting fluid is hard on the cylinder.

 

That is a true statement.  It burns dry instead of wet like fuel or carb cleaner.

 

Ben W.


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#12 superaben OFFLINE  

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Posted January 20, 2015 - 09:14 PM

the magneto can be rotated a ways to adjust static timing. If off far enough it would be like a sheared key.

another possibility   I had an uncle "tune up" a Tecumseh powered push mower once, he put the condenser on upside down and the flywheel wore the condenser wire in two. (but you say you do have spark, I just thought I'd toss it out there)

 

Ah, great minds think alike!

 

Here are the instructions, they are for an H60 but the principle should be the same.

 

Attached File  Tecumseh Troy Bilt Tuneup.pdf   6MB   140 downloads

 

Ben W.


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#13 GTTinkerer OFFLINE  

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Posted January 20, 2015 - 09:31 PM

Page 6 of the above tune up instructions show how to time the engine.  I use a straight edge across the top of the cylinder and .063" in feeler gauges to set the timing.  The PDF says 1/16" which would be .0625" but using a feeler gauge eliminates some guesstimating.


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#14 dodge trucker ONLINE  

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Posted January 20, 2015 - 10:44 PM

the measurement varies on the engine series, in the specs section of every Tecumseh manual I have seen that covers the point ignition models  it will list how much below TDC in  thousandths... kinda hard to do it w/a timing lite and rotate the stator when it is under the flywheel....



#15 FilledTires OFFLINE  

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Posted January 21, 2015 - 05:53 AM

Ah thank you everyone! I am going to put all this to work.




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