Tecumseh 10hp Will Not Start

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  #1  
Old 01-27-20, 06:48 AM
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Tecumseh 10hp Will Not Start

Hope someone here can help!
Working on a PowerBack generator mod. GT5250 with a Tecumseh 10hp. mod. HM100. Needed TLC! Replaced fuel lines and installed a new carb. Checked spark, good, plug good, compression, good. Started and ran for a good bit. Recoil broke. Added new recoil rope and spring, now she will not start. Tried starting fluid, nothing. Kind of a rumble but no start. Rechecked spark, fuel and compression. All good. All suggestions are welcome!! Thank you in advance.
 
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  #2  
Old 01-27-20, 07:07 AM
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Could be flooded. Try removing the air filter when starting.
 
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Old 01-27-20, 07:29 AM
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Thank you Wirepuller38. Removed air filter and there was no change, no start. I also looked at the plug and it was dry.
 
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Old 01-27-20, 11:04 AM
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Check the carb bowl. Maybe some water or trash got in.
 
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Old 01-28-20, 05:05 AM
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In post 1 you state the fuel is good. In post 3 you say the plug is dry. Is this a change or did post 1 not include fuel in the combustion chamber? Any chance the flywheel could have slipped on the crankshaft?
 
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Old 01-28-20, 04:03 PM
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Yes...new fuel, drained and filled with new fuel. I checked the plug to see if was wet incase it was flooding. Doesn't seem to be flooding. You brought up a good point. I did not check to see if the flywheel has slipped. Will check that tonight. Thank you for your input! Really want to get this running again. When it ran before initially, ran good, electrical output was good. The generator part must be working fine. Does seem to be difficult to pull (trying to start), Not sure if this is normal or not....
 
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Old 01-28-20, 04:44 PM
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Have you removed the plug to test it visually when you pull the recoil starter? Is it hard to pull with the plug removed?
 
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Old 01-28-20, 07:54 PM
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I am new here and know just enough to be dangerous. I have one of these engines on a Coleman generator. It is about 20 years old but build better than what is available today. I'm keeping it until is dies.

When you are stumped and frustrated it is really easy to chase your tail, so to speak. I move on to something else and try to forget it for a while. That said, I would start over and methodically go through it again. Except for the use of starting fluid, this sounds like extreme fuel starvation to me.
 
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Old 01-29-20, 02:52 PM
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I haven't noticed in the posts, have you put a spoonful of fuel in the plug hole to see if it will try to start, if it will fire a few times then we know its fuel flow related. Have a good one. Geo
 
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Old 01-30-20, 05:49 AM
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Eagle_51
Just like Geogrubb states, do you get anything when you put fuel directly into the cylinder?
I am guessing that you are testing the sparkplug for spark by connecting the high tension lead to the plug and grounding the plug. You say you have spark but does the plug actually make spark when it is in the cylinder under full compression. I've had instances when the spark looks good outside the cylinder but fails in the cylinder. Maybe change the plug and try again.
Hope this helps.
Snoman100
 
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Old 01-30-20, 03:48 PM
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Well crap....
Thank you Wml13, Oldfud, geogrub and snowman. I read your recommendations and went back to the garage to follow your recommendations. Unfortunately I determined that the piston is not cycling up and down as I pull the recoil cord. Guess that there is an internal malfunction. I did put new oil in before I tried starting and I guess that did not help. thank you all for your suggestions and recommendations!!!
 
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Old 01-30-20, 03:58 PM
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When I look into the spark plug hole and pull the starter rope, the piston does not move up and down. I see a small piece on the side of the piston move but that is all. Thanks again for you help!! Wishing you all well with your projects!!!
 
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Old 01-31-20, 05:43 AM
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Please explain how you measured good compression in post #1 or did you do something detrimental to the engine between posts 1 and 12?
 
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Old 01-31-20, 04:05 PM
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Checked compression with a gauge. Read 30 psi. Seemed low but consistent. Started and ran good. After running for a about 20 mins. (with a load...fan) shut down to re-do wiring. Shut down fine. Made repairs to wires and tried to restart and no luck. Wasn't till I was double checking the plug for spark when I noticed that the piston was not moving. For the life of me, I can not figure out what happened to the piston!
 
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Old 01-31-20, 05:47 PM
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You may be looking at a valve and not the piston when you see movement.
The 30 PSI wouldn't run the engine. And if it was running OK with oil in it, I doubt if the piston/rod/crank came apart.
You need to take the starter recoil off so you can work with the crank directly. Rotate it back and forth with a dowel through the plug hole and resting on the piston. See how it moves with rotating the crank.
 
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Old 02-01-20, 01:26 PM
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Thank you marbobj. inserted dowel and turned crank. Dowel did not move.
 
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Old 02-01-20, 02:10 PM
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Can you push the piston down against the crank with the dowel? With that done moving the crank should move the piston either on the "for or aft" rotation.

Odd that it came apart like it did, but you see just about everything. Usually with that type of damage, it's fixable if the block didn't have significant damage.
 
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Old 02-01-20, 02:29 PM
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there is not a budge if I try to push down on the piston with the dowel.
That is what is most confusing to me. she ran fine. I shut down to work on wiring.
that kind of damage would have been catastrophic in sound or in operation.
 
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Old 02-01-20, 02:54 PM
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There would be some guessing with the piston freezing in the cylinder. Then in addition to that having the crank disconnected, apparently from the rod blowing out

On that engine, though, the spark plug hole is above the valves and not the piston. The question is are you sure you're watching the piston? Also, are you sure you have the dowel on the piston and not simply on the block by the valves? With the configuration of the head/spark plug hole relative to the cylinder, you may not be able to set the dowel on the piston.

If the piston is actually frozen in the cylinder, though, it would have to be taken apart to diagnose and fix.
 

Last edited by marbobj; 02-01-20 at 05:26 PM.
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Old 02-02-20, 07:36 AM
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I did not know that the valves were above the piston. That would explain what I am seeing/not seeing. I will take a closer look today. I really could not understand why it ran and then, (after simply repairing wires) the piston would seize. There was no traumatic noise or movement when I shut her down. Thank you marbobj for taking the time to help me out!!!!!
 
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Old 02-02-20, 09:34 AM
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No problem. Those valves aren't above the piston. The valve stems are parallel to the travel of the piston and set to the side of the cylinder. Think of it in terms of the valves and the top of the piston are level with each other when the piston is at the top of its stroke (specifically the compression stroke).. Your valves come up from the bottom. In other engines they open from the top = overheads.

Look at the cylinder - part # 1 - about the center of the diagram.

https://az417944.vo.msecnd.net/diagr...st/diagram.gif
 
  #22  
Old 02-02-20, 09:41 AM
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The only thing that changed since it was running is you worked on the recoil starter rope, could have something with that causing the harder pull. And since the shut down to re-do wiring it won't start so I would suggest you go through all the wiring you worked on looking for something out of place or grounding issues.
 
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Old 02-02-20, 10:21 AM
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Rope was frayed from the beginning. Did not seem like there was an internal problem Crank still turns with the same tension as it was when it ran. Thinking back, if the piston was seized, the crank would not rotate, unless piston rod was broken and in that case, the crank would turn easily. Plug has good spark after I worked on wires. Looking through the plug hole now.
 
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Old 02-02-20, 10:40 AM
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When looking down the plug hole, I can see a valve cycle and the piston move up and down.
 
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Old 02-02-20, 10:46 AM
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When looking down the plug hole, I can see a valve cycle and the piston move up and down. Plug has a clear blue spark.
 
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Old 02-02-20, 11:51 AM
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Good.

Now spin the engine over half dozen times with the choke off and the throttle wide open and the spark plug out. Then put a spoon of gas down the plug hole, the spark plug back in, and see if it will start. If it tries, move the choke to half on and the throttle to half on and see if it will take off and run for you.
 
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Old 02-02-20, 01:54 PM
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Will do. Since it's a generator and there in no throttle, does that make a difference?
 
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Old 02-02-20, 07:29 PM
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The full throttle is to clear out flooding. You can do the same thing with no choke and the fuel to the carburetor shut off. Once it's purged, go to normal starting procedures.
 
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Old 02-03-20, 02:32 PM
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HOLY CRAP marbobj...followed you instructions and she started right up!
Let her run for twenty min. Picked up a new compression gauge to see if my initial readings of 30 psi are accurate. I cant imagine that it would start or run with compression that low. Waiting for her to cool and I will check with new gauge.
 
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Old 02-03-20, 04:26 PM
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That's great. Yep 30 is too low to run on.
 
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Old 02-04-20, 01:24 PM
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There must be some throttle control for the engine because the engine speed determines the votage frequency developed by the generator which needs to be 60 hertz in the US.
 
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