# tecumseh wont start



## jawlessemu (Nov 12, 2008)

i bought a used 12 horsepower ohv tecumseh engine over the weekend for my riding mower. the old one just wouldnt start and turned over very slow on compression. so i got the new one home put it on the mower and went to start it and i still have the same problem. it seems that the when the engine is turning over it gets to a point were its built up alot of compression and it turns to slow to start. anyone got any suggestions as to whats wrong?


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## Basementgeek (Feb 7, 2005)

Eletric start or pull start ?

BG


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## jawlessemu (Nov 12, 2008)

its electric start


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## MrChooks (Apr 19, 2008)

:wave: Sounds like a sick battery, battery connections or starter motor.

Have you tried it using a different battery - maybe jump leads from your car battery - if that works - then its the battery - 

If not, the starter motor might need a service (worn brushes / commutator can cause these symptoms). Also poor connections - (look especially where the battery negative (ground) is bolted to the frame of the mower) are another likely suspect.


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## jawlessemu (Nov 12, 2008)

ok i fixed it. i took off the overhead valve cover and checked the rocker arms and one of them was loose i tightened it up and presto the super high compression is gone and it turns over like it should. but is there any standard for torque on the nuts on the rocker studs?


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## MrChooks (Apr 19, 2008)

:wave: Well done -I would never have thought of that - would be still looking at starter motor 

The head torques and other torques are usually set out in the owners manual - if you don't have that - then they can be downloaded from B&S web site - all you need to do is put in the engine model number

Here is the link to B&S site:

http://www.briggsandstratton.com/maint_repair/manual_and_more/


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## Basementgeek (Feb 7, 2005)

Not BS engine, it's a tecumseh


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## MrChooks (Apr 19, 2008)

:wave: BG - you might have a couple of years on me - but that doesn't stop me from having "seniors' moments":sigh: I forgot to look at the original post - I just get sillier as I get older - 

jawlessemu - apologies - I led you to the wrong web site (your engine isn't a B&S) - nonetheless, I am pretty sure that Tecumseh also have their engine docs posted on their web site - I just don't have the link for it -


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## jawlessemu (Nov 12, 2008)

well i finally got the engine running. . . . . sort of. after i set the lash on the valves and adjusted the carb it finally starts. the problem im having is that the carb seems to be pulling an axcessive amount of air. it will only start with my hand choking it and once it is started and running i have to continue to hand choke because if i dont it will just rev extremely high even with the throttle on less then 1/4. any got any suggestions.


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## jawlessemu (Nov 12, 2008)

also it seems as thought the engine is backfiring through the carb i can see a flame every once in a while along with a loud ping although im not sure what the noise is. and it only occurs while it idling down


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## MrChooks (Apr 19, 2008)

:wave: Well done of getting it going -

That you need to hand choke to start leads me to think there is a float or jet problem - have you cleaned the main jet thoroughly (every little hole must be clear)

The high speed idle makes me wonder if you have the throttle set too wide or getting too much fuel or that your governor connection / links are not right - can you make the engine idle at a respectable speed by moving the governor link / throttle setting???

With the flame etc from the exhaust - that is usually associated with mixture issues - see if you have the needle and seat / float set properly (Tecumseh sometimes have adjustable floats) - so see if you can reset the float to the correct level and see how that goes.


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## jawlessemu (Nov 12, 2008)

ok first i dont have the governor setup beacuse the governor links were not there.and the high speed isle occurs only when i remove my hand from the carb while im choking it. so i dont know exactly whats going on with that. i will try cleaning the jets. the other thig is the exhaust is producing a flame when idling down but what had me more concerned was that the carb was also acting the same way a small blue flame will occasionally shoot out when idling down.:upset:


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## MrChooks (Apr 19, 2008)

:wave: If the engine was designed to operate with a governor - then I am pretty sure you are going to have to put it back in service (can you scavenge parts for this from your old engine??).

If the engine was built with a governor - then that is likely to be a big part of the issues you are having with getting stable engine speeds and because the throttle setting will be all over the place without a governor connected - maybe a good part of your problem with backfiring through the exhaust and carb.

Lastly and as a word of caution - if the engine has a governor controlled carb but you have the governor disconnected - there is a real risk that it will over rev big time - and then there will be bits of engine all over the place :4-thatsba


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## jawlessemu (Nov 12, 2008)

ill try and find some old carb links. i and i wasnt aware that is was that big a deal. i thought since i use a throttle cable style control i would control it all from there and the governor would be useless. but i guess not. ill try to hook something up and hope it works


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## MrChooks (Apr 19, 2008)

:wave: No - governed engines have a different carb set up to that in an old car engine - so the throttle cable moves the governor setting and the governor link then closes the carb throttle plate to bring the engine up to speed, once it reaches the appropriate speed, the governor then opens the throttle plate to reduce the fuel flow. That way you can set the engine to operate at a set speed and regardless of the load (within the engines operating performance curve) the engine will maintain the same engine speed. This is a very useful function for yard equipment such as mower, snow blowers, shredders etc - as it means you do not have to continually adjust the throttle - so it's sorta like a "cruise control" on a car.

But because the carb set up and linkages are all designed around inputs from the governor - if you run then engine with out one connected and operating - there is a real risk of the engine going "run-away" and that nearly always leads to KA-BOOM and its all over:4-thatsba


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## SABL (Jul 4, 2008)

Hi JE,

Will this help?? 

http://toprake.com/index.php?module=documents&JAS_DocumentManager_op=downloadFile&JAS_File_id=9

Take a look at chapter 4 and see if anything looks familiar.

Best of luck,
SABL


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## MrChooks (Apr 19, 2008)

:wave::wave::wave: SABL - You are a hero -tks heaps - I have been looking for one of these books for ages.ray:

JE - armed with SABL's info you should be set. I would also suggest you go down to an outdoor equipment shop (one with a fair range of new and used equipment on display) and have a look at any equipment with engines similar to yours - that way you can see exactly how the governor links are arranged and what parts you are likely to need. (Sort of like a little bit of industrial espionage :grin. Then, once you know what bits you need and armed with the info SABL posted - you shouldn't have too much trouble getting the governor / throttle arrangements sorted out

Good luck with it all


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## SABL (Jul 4, 2008)

MrChooks,

You are the one to be admired. I get lucky on occasion.

Let's agree on one thing..... a governor is a MUST. Throttle control is absolute in the operation of any machine.... the operator has to remain focused on the job at hand and the governor maintains the engine speed that is necessary to perform the job.

No matter how small it might seem, never over-ride the governor of your equipment and the safety that is provided by its use. The safety that is intended by a governor is for you and the actual piece of equipment...may you both live long and prosper.


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## MrChooks (Apr 19, 2008)

:wave: Tks SABL - 

Yes, agree wholeheartedly - running these engines without a governor functioning properly is a recipe for "lots of tears before bedtime!!!). It takes no time for an ungoverned engine to go runaway - then there are bits of engine all over the place - (and like Humpty Dumpty) - none of which will ever fit back together again


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## jawlessemu (Nov 12, 2008)

well i got the governor hooked back up i found the original governor rods. but im still having the same problem with having to manually choke it to get it to start andhave to manually choke it to get it to continue to stay running. i have also noticed there is fuel dripping out of the back of the carb were the air filter would connect. i just cant figure why it needs to be manually choked. could it possibly have anything to do with the valves? or is there a setting on the carb. i looked in the manual and i didnt see anything about it.


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## MrChooks (Apr 19, 2008)

:wave: OK - now sounds like some of the carb settings are out - the fuel leaking makes me think that the needle & seat / float valve may need repair and if that is way out, it can cause issues with starting.

Your need for choke to keep the engine running sounds like the atmosphere vent in the carb / main jet is blocked - have a look at the manual SABL sent - to see where this is on your carb

So I would get hold of a carb overhaul kit (they usually contain all the bit you need to do up a carb) and when you have the main jet out - make sure ALL the little tiny holes in the jet are clear (there are often some up the side of the jet as well and these need to be clear as well)

Have a look at Chapter 3 (pages 12+) in the manual that SABL posted earlier - you should be able to identify which is your carb and what you need to do to give the old carb a service.

See how you go once the carb has had a clean up and you have the jets adjusted OK and let us know


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## jawlessemu (Nov 12, 2008)

ok so i rebuilt the whole carb and cleaned everything. i got the engine running. . . . . but it will only idle if i give it any throttle it dies out. however i can get it to run at any throttle with about 1/4 choke. i reset the carb to all factory presets and still it wont run right i dont understand.


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## MrChooks (Apr 19, 2008)

:wave:OK, if it runs fine with 1/4 choke (and you have allowed it to warm up - as if the engine is cold - it will likely need choke until it is warm) I suspect that either there is still some muck in the main jet or the float level is too low and / or the main jet need adjusting.

Does your engine have an adjustable main jet - if so, then if ALL the jet holes are clear and the float level is correct, you should be able to "tune" out this issue with small adjustments of the main jet.

Have a look at the manual SABL posted Nov 22 (Chapter 3, Page 13+) - this will show you how to adjust the jets and get the carb / engine running smoothly


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## jawlessemu (Nov 12, 2008)

i finally got everything running fine it was idling nice and everything. but then bang the engines stops daed and now its seized for some reason. oooooooooohhhhhhhh i am pissed all that work and time and money and now its dead.:upset::upset::upset::upset:


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## MrChooks (Apr 19, 2008)

:wave: Hey jawlessemu, that is a total BUMMER:upset::upset::upset: 

From your description - it sounds like a big end bearing or con rod may have come adrift - let's hope so, as that may not have done too much damage to the bores and your engine may still be a fixable proposition

Don't attempt to turn the engine over until you have opened up the crank case and had a look at what has come adrift and freed up anything that has become jammed.

If it is only a big end then it may be an economically fixable proposition (my view with small engines is once the crankshaft has gone or the bores badly scored - it's better to get another engine - too many parts just kills the economics of a repair) - but if you only need a big end and / or con rod, and you are a bit handy - even though its a big job - its quite doable:sigh:


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## MrChooks (Apr 19, 2008)

:wave: hey jawlessemu - just had a thought - and I am assuming that your now dead engine is the same as your old engine - once you get inside and figure out what is wrong - you might be able to scavenge some parts from your oldie.

If it's a con rod or big end - then you will need new bearing and rings or other "mating parts" I would guess - but you may be able to use your old engine's con rods, pistons etc. I know it's not as good as new bits and no doubt some of my TSF colleagues will be wincing at the thought (and probably start throwing rocks at me :4-surrend) - but will help to keep the repair costs down


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## jawlessemu (Nov 12, 2008)

well im already thinking of getting a new engine i found a 16hp two cylinder tecumseh for 100$ that runs and ill put my seized on away for a rainy day. but that will put me in over 200$ in engines with only one working.


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## MrChooks (Apr 19, 2008)

:wave: OK that is a good plan also - just make sure the vendor can show you the new engine running (easy start, throttle up and idle) before you hand over your $s. 

If it will work properly on the vendor's bench - then it should work OK for you. Just make sure that it's foot print is the same as you old engine - so that the transplant will be relatively painless:sigh:

By foot print - I mean, shaft length and diameter, same key-way size, same shaft centre height and matching face plate bolt hole pattern.


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