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Discussion Starter · #1 ·
My push mower is a very simple 21" high-wheel MTD with a 6.5hp B&S engine on it. No self propel or any of that. It's about 10 years old. I always run gas with Stabil in all of my small engines. Typically the mower has always started on the first or second pull, until recently. Now I can pull 10-20 times and so far it eventually springs to life, but I don't know if that will be true next weekend.

All I do to it is change the oil and keep the air filter clean, and my knowledge of engines is that it's the noisy thing that spins right? Whilst trying to start it I have done things such as unscrew and tap dirt out of the air filter and reset the spark plug wire. Like I said, it eventually starts but I don't know if anything I'm doing makes it better or worse. Anyone have ideas what would make it hard starting? Once it starts it runs the same as it always did. Would a dose of Seafoam be a good idea?
 

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ggsteve,
The Seafoam would probably help clean the carb, but I think you need to change the spark plug. You can; I think; still get a manual for your mower from MTD at their web site.
Dave
 

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Changing the sparkplug is a good first step but if it's getting hard to start,chances are the choke isn't working correctly.First off,does it have a choke or a primer bulb?If it's a choke,I would pull the air cleaner off and see if it's closing like it's suppose to.
 

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Discussion Starter · #4 ·
Changing the sparkplug is a good first step but if it's getting hard to start,chances are the choke isn't working correctly.First off,does it have a choke or a primer bulb?If it's a choke,I would pull the air cleaner off and see if it's closing like it's suppose to.
It has a primer bulb. I usually give it 4-5 squeezes to prime it.
 

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Can you feel if it's pumping fuel?Sometimes the bulbs or lines will get a pinhole in them and not actually be pumping any fuel.You could try taking the air cleaner off and using your hand over the air horn on the carb to choke it,if you can do it safely.If you choke it with your hand don't choke it more than once or twice at most,then pull it normally,if it starts right up that way,your primer bulb isn't working.
 

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Discussion Starter · #6 ·
I think I'll put in a new plug and try the Seafoam. I'll also check for leaks in the primer. It's been a long time since I changed a plug. Is about a 1/4 turn beyond hand tight ok?

Also, should I run the seafoam through the engine before or after I put in the new plug?
 

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a quarter turn might be too much, especially if it's the same plug without a new gasket. Torque specs are usually in the manual. I go by feel after doing it many years. Aluminum heads require extra care.
 

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Also, it's a very good idea to use some anti-sieze compound on spark plug threads. I use it on everything I take apart, and it's really easy to remove the bolts/screws/plug the next time around.
Just make sure you don't get any of the compound on the nose of the plug - it'll short the plug out. Just a small dab on the threads will prevent galling, and make the aluminum threads last much longer.
 

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Discussion Starter · #9 ·
Well, this week it started on the first pull and I didn't do anything! Thanks for all the suggestions, I'm still going to proceed to avoid trouble in the future. I think I'll do the same to my old Toro walk behind snowblower.
 

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your post inspired me to go look at an old Murray that I have....
My advice is push the bulb while looking inside the carb. You should see a squirt of gas. Right guys? Maybe his is different...I dunno. Mine had no hose connected to the bulb, just an outlet that went thru the filter case into where the gasket is...I think. I dont understand how it works, just does.
 

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Actually that mower came for free and has been sitting in the rain for at least 10 years. I pulled the carb off just now and replaced with one off a brand new fancy craftsman with thrown rod ( must be common to those)
anyway, the dang thing started on second pull...and I could not get it to shut off without pulling plug wire.
 

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Yah when you push that bulb if your looking in the carb you should see some fuel squirting, but I would try to give her a quick tune up maybe your gas line could be coming apart also, I've had problems with those mtd push mowers before like that. All I did was take the carb apart clean it all up just make sure that you keep all the little pieces from the fuel pump there still. I've had that linkage for the choke go bad also, there should be a spring in there that pulls the choke when you move the throttle cable that spring could be worn out.
 

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Make sure that when you squeeze the brake handle that there is enough travel to disconnect the ground switch to the coil. It is visible from the exhaust side of the engine.
 
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