Lawnmower engine repair

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I got a Yard Machines lawnmower for free with a Tecumseh 4.5hp engine but it's not running. It's not supposed to be much more than a year old. But I just found out it sat for almost a year too(with gas in it).
It's got that stupid automatic throttle which I'm not quite sure how it works. I don't have too much experience with carbs either. I can fix my car but I don't have a clue what to do with a carb. Maybe I could retrofit Motronic fuel injection to it!
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It would run on starting fluid if I sprayed the air filter. So obviously some kind of fuel delivery problem... I put a bit of fuel system cleaner after I found out it sat. And it would run for few few minutes but roughly.
I took the carb, intake, and muffler off and everything is clean as a whistle.
I even took the tank off and completely drained it and put all fresh gas in, in case some old stuff was left over. Still no luck.
Any ideas?
The carb doesn't look that complex, so I don't see what else I am able to do with it. Especially since it is clean. The only thing I didn't take off is the float bowl (I think that's what it is).
Any help is greatly appreciated...I'm not too thrilled with the idea of buying a new one. And it's not worth paying to fix this cheapie model.
 
Given the fact that you can start this unit with the spray here is the info on how to fix your problem.

Look at this diagram.. where 19 is particularly.

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This is what causes most all no start conditions for small engines that have not been run for a long time as the fuel will varnish and breakdown clogging the fuel pickup in the bowl. When this happens, the fuel cannot get into engine.

One note here, When you open the bowl with the bottom screw, fuel should be present. That is another indicator that the float is not the problem. On occassion, floats do stick but tendacy is wide open if they were empty a long time. Many times, just tapping the side of the carb bowl with a small hammer(or handle of screwdriver or such), very carefully not to hit it really hard and crack the bowl, this will unstick a float.

back to the pickup, if the bowl has fuel in it when taken off, then you need to get a little metal piece of wire and clean this out and your problem will be solved...notice the small holes on the side, and one on the top.

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This problem can be avoided with using a fuel stabilizer like the neutra 131 in the fuel. That will keep the fuel from breaking down and causing this problem.

Hope this helps.
bob

[ August 29, 2002, 02:25 PM: Message edited by: BOBISTHEOILGUY ]
 
Hehe yeah maybe on second thought I don't want to fix it
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Pretty sure its no gas. The plug is always dry. And it doesn't smoke.
Although it must be getting some, because when I was running it on the starting fluid, the gas level dropped in the tank eventually a bit.

Well I'll open up the float bowl and take a look and clean it up. Thanks.
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Jason,

It's easy. You'll have it running no time.

Big thing to remember, clean the bowl, and anything you can get to without getting into a major deal, but just by cleaning that bottom bolt out,as it is what lets the engine suck the fuel from the bowl, you'll start to get gas.

One other thing, use your primer(if it has one) and pump a few strokes in when you see gas in it.
Now set the choke on, pull / try to start it.
you do this a few times until the engine "kicks" a little(like it might start) at that point, you have fuel in the cyl., Now turn off the choke and re start, and it will start. It may start and die, if so, then rechoke, kick,the off the choke and it will.

A lot of people don't know that little proceedure so figured if not for you some one else may be able to use it.

bob
 
Gee Bob, you get all those nice picures.
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Another thing to consider is the needle mixture valve. What I do is count the number of threads at it's present position, and then back it out and clean off the crud, then turn it back to the number of turns it was at before. Also, some needle valves have that pesky little black seal which, if it isn't riding tight on the needle valve or if worn or cracked, will allow too much air to be sucked around the needle valve.
 
Float bowl. IMSLE, that's the first thing to check in your situation, not the last. Does it act like it's getting no gas at all, or like it's flooding all the time? Either can be indicative or float valve problems, stuck shut, or stuck open. Some mowers, if gas is gravity fed, can even fill up the crankcase w/gas when FV sticks open.

Check the float bowl & valve, have a can of carb cleaner handy, clean & check, & then you're probably out of excuses, & gotta go mow that #$%&* yard!
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Yeah there was some gunk at the bottom of the bowl, and I cleaned everything up and now she purrs like a kitten.
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Didn't have to use a wire on the retainer, just used the carb cleaner. Besides the side hole was probably less than .015". So unless I was going to pluck one of my hairs and stick in there.... not much else would fit.
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Changed the oil. Now she's runninng 10w30 SS
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Should I get it analyzed ? Too bad I didn't have any Red Line 10w30 on hand.
By the way, about what is the capacity on these things? When I refilled, it took about 550mL to get to full. Think I got all the old stuff out? They need to make the oil easier to change too.

Thanks again!
 
Bob, Touche!
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Jason,

By all means get it analyzed at the end of the season. You'll be the first. I was hoping that dragboat would do that on his new, ported mower with the glistening chrome pipes coming out the top.
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Mowers are tougher than you think. I just opened up a 25 year old mower with a B&S 3.0 HP engine (that's when I had a small yard) that had been sitting in the junk pile for 7 years or so.

I pulled the head of the engine and the hatch marks were still visible; bearings were still tight, and had over 2500 hours on it before the carb died. I had run Amsoil 10W40 AMO in it.
 
Jason,

BTW, the valves were tight and the compression was high before the head was pulled.
Now I use it as a motored test engine.

The capacity will range from about 600mL to 1.75 L depending on size. The 10W30 SS should be a good oil for it.
 
I have a similar mower (MTD with a 5HP Tecumseh). Oil capacity is 21 oz.

Check out MTD's website; they have downloadable owners manuals and engine manuals. Helped me a ton as I got my MTD free as well. Don't ya just love a free mower??

BTW, looks like I've got to switch to 10W-30 Tri Syn just to keep up with y'all. Wish I had a local source for Schaeffer's. I could use a little Neutra to purge the Pep Boys 30W.
 
Molakule, maybe I will next year...unless we get some more rain. It doesn't look like I will be cutting the grass much more this year.
HA! he did that to his lawnmower? sweet.
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You're right, I checked Tecumseh's web site, it's 21 oz, so I wasn't able to get ~60mL...

Thanks bretfraz, that's a good site. I'll have to get my s/n when I get home to pull up the manual...
 
Originally Posted By: exranger06
Great job reviving a 6 1/2 year old thread!!
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That's exacally why I did it!!!!!!!!!!!!!!!!!!!!!!!!!
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welcome back!!!!!!!!

I did it just for the heck of it!
 
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