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Discussion Starter · #1 · (Edited)
I have a Yard Machines (by MTD), not used for a while but now it can't start.
I replace the spark plug, air filter and still not solve the problem.
5.5 HP, 21 inch cut
MTD model: 11A-416Q729.
It worked fine before and just long time not using.
What's wrong with it?
Anybody knows? Please help.
 

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Retired Moderator
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I moved this to 'small engines /tractors"---Mike----
 

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Are you getting spark? Sometimes rust on the flywheel will cause the magnito to malfunction.

That's a bit of work to fix--so see if the spark plug wire is getting juice---
 

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Need a whole lot more info.
Start from turning the key, what happens.
Big differance from does nothing when key is turned and turns over but will not start.
Still got old gas in it?
 

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Discussion Starter · #7 ·
My Mover is just need a little more energy

Sorry, I really don't know how to post my thread to certain folders in this forum.

My mover is just works fine and can feel that it needs a little energy to start but I don't know how to adjust it. New Spark Plug, new filter. I think it is no spark when pulling the string.

It is a not too old mower. Yard Machines (by MTD),
5.5 HP, 21 inch cut.
MTD model: 11A-416Q729.
It worked fine before and just long time not using.

Anybody knows? Please help.
 

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Works fine, but no spark? Hmm.
If there was no spark it would not run.
99% of the time the carberator needs to be removed and rebuilt.
 

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A Little Of Everything
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Sorry, I really don't know how to post my thread to certain folders in this forum.

My mover is just works fine and can feel that it needs a little energy to start but I don't know how to adjust it. New Spark Plug, new filter. I think it is no spark when pulling the string.

It is a not too old mower. Yard Machines (by MTD),
5.5 HP, 21 inch cut.
MTD model: 11A-416Q729.
It worked fine before and just long time not using.

Anybody knows? Please help.
If it will not start at all, after not running for quite awhile, it's almost a guarantee that your gas got old & plugged up your carb.

Usually you can drain out the old gas, and put in new. Remover the air cleaner and give it a shot of starting fluid (you can buy this for about $4 at any auto parts store). It should start, run really rough for a bit, but smooth out.

If you get it running, add a little SeaFoam to the gas. It will clean up the carb.

If you do NOT get it running, let us know & we can go from there.


In the future, before you stop using your mower for the winter, add a little bit of SeaFoam.
 

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Discussion Starter · #10 · (Edited)
Thanks. I sprayed the Quick Fluid to the Carb. and the engine started running but stopped immediately. The oil or gas or combination of both was spreaded (pushed) out from the exhaust window when engine was running short time. Is it the problem of engine oil leaking or something else. Should replace the engine oil? How to drain it? Where is the leak. How to fix it?
 

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Master General ReEngineer
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Thanks. I sprayed the Quick Fluid to the Carb. and the engine started running but stopped immediately. The oil or gas or combination of both was spreaded (pushed) out from the exhaust window when engine was running short time. Is it the problem of engine oil leaking or something else. Should replace the engine oil? How to drain it? Where is the leak. How to fix it?
Ayuh,... The Carb needs to be removed, 'n Rebuilt....
 

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Roofmaster
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Just take it to a mower repair shop, for goodness sakes. The EXHAUST WINDOW???? C'mon man you are over your head!
 

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I have the same problem with my MTD mover 11A-416Q729. It was used about a month ago and now won't start. Is the spark plug spark suppose to be yellow or a blue? I check the plug for spark and it sparks but it's a yellow color. I'm thinking it's suppose to be a blue colored spark? And does the primer red rubber button suppose to pump enough gas into the carb so I can see it pumping in when I remove the outside cover?
Thanks, Brad
 

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A Little Of Everything
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I have the same problem with my MTD mover 11A-416Q729. It was used about a month ago and now won't start. Is the spark plug spark suppose to be yellow or a blue? I check the plug for spark and it sparks but it's a yellow color. I'm thinking it's suppose to be a blue colored spark? And does the primer red rubber button suppose to pump enough gas into the carb so I can see it pumping in when I remove the outside cover?
Thanks, Brad
The easiest way to tell if it's a gas or a spark problem is to shoot a little starting fluid in the carb (remove the air filter first) then try to start it. If it fires up then dies, you've got a fuel problem. You then work backwards from there.

My guess is that you've got some varnished gas blocking one of the orifices in your carb.
 

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The easiest way to tell if it's a gas or a spark problem is to shoot a little starting fluid in the carb (remove the air filter first) then try to start it. If it fires up then dies, you've got a fuel problem. You then work backwards from there.

My guess is that you've got some varnished gas blocking one of the orifices in your carb.

Thanks Dr. Hicks....... found out it MUST be the carburetor. Sprayed some of that fancy starting fluid into the carb and worked for 5 seconds. Actually that was a good thing since I was not looking forward to any additional work. Replaced the fuel line next and tried again.... worked for 5 seconds again so must be the carb. Gas was new so no old gas but that varnish is a killer. Can't think of how many times that screws things up. Anything you can use to keep that crap out of the carb? Or just some of that seafoam stuff? Maybe just run it more than once a month will help. Anyway, thanks for the heads up on the spark plug... (already replaced it for under 3 bucks. Got a couple new springs, (air vein and governor), filter, breather tube, primer bulb, and carb rebuild kit all for under 35 bucks.... sure beats the heck out of taking it to the shop.... probably better off buying a new one rather than take it to the shop.... Thanks again......... Brad
 

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Thanks. I sprayed the Quick Fluid to the Carb. and the engine started running but stopped immediately. The oil or gas or combination of both was spreaded (pushed) out from the exhaust window when engine was running short time. Is it the problem of engine oil leaking or something else. Should replace the engine oil? How to drain it? Where is the leak. How to fix it?
The oil in the crankcase travels thru the valves area and then into the head if the lawnmower is tilted wrong. Oil also gets into the head with you have broken piston rings. Compression test will tell you
 

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John
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Compression test on these engines WON'T tell you !
They have a compression release arm,on the cam, that is activated by centrifugal force .
The standard test for compression on the 3.5 to 6.5 engines,is to spin it ,by hand(with the spark plug wire off the plug!). just a quick flip. If it bounces back,it has compression.
Note,also that these engines only take 16 to 20 ounces of oil! Any more than that,and it will run into the cylinder,and cause lock up,or hard starting,and smoking.When the oil level is at the "add" mark,it will take 4 ounces.
Always make sure that the front,and rear wheels are adjusted the same height,for this reason !NEVER tip them sideways,or plug downwards!.
If you have to tip it(to clean under the deck,etc) tip it so the spark plug is UP !
 
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