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I'm completely stumped as to what is wrong with this thing. It's a SEARS craftsman eager-1 4.5hp 22" engine model 143.964502.

It starts on the first try, runs for as long as 10 minutes, and as soon as I'm cutting a thick section of grass it starts surging and then dies. Then it won't restart (no kickback, just smooth pulling and no start.) unless I wait like 30 minutes. After that it starts but shows the same behavior.

I replaced the ignition coil, air filter, and spark plug. I removed the bolt on the bottom of the carb and cleaned the [one] hole in it, no change. I've removed the spark plug when it dies and it looks dry. No fuel, which suggests a fuel starvation issue.

I got the mower from a guy on craigslist and it has done this since day one. I'm an auto mechanic so I'm mechanically inclined but I have no clue how to fix this thing.

A few things I noticed:



It doesn't have a primer bulb rubber thing. It's my understanding that this section of the carb should have a bulb. Can a missing bulb cause issues?





Also does that flywheel key look OK?

Picture of the whole mower:

Hook up an alternate fuel tank and see if the problem persists.
The fuel filter inside the tank does clog up and the fuel lines themselves split so the carb sucks air not fuel.
So a partially clogged filter will take a while to allow fuel in.
Modern fuel accentuates this problem.

Usually a 30 minute run the total close down till the engine cools down completely is a bad ignition module.
Occasionally a brand new one is bad so check for a spark the instant the engine dies.

To check for spark all I have to do is pull the start cable right? And the kill wire has to be disconnected?

I know how to do the spark plug/wire part. If i pull the start cable, there should be spark right?

Pull the plug Then Plug it in to the spark plug wire and ground it to the engine you should see a faint blue spark as you turn it over.

Cars_to_mowers said:

To check for spark all I have to do is pull the start cable right? And the kill wire has to be disconnected?

I know how to do the spark plug/wire part. If i pull the start cable, there should be spark right?

Click to expand...

It is best to use an inline plug tester.
I use the neon tube kink cause these old eyes aint as sharp as they used to be.
Check for a spark with the plug in the cylinder and again with the plug out & earthed against the cases.

I have a "genuine rebuilt Stihl 070 " in the workshop right now ( cheap Chineese fake ) which will not spark when the plug is in the cylinder.
The customer is about to send me the third replacement to see if we can get it to work.
I no longer fix fakes unless the customer supplies the parts.

This one is a no brainer and you should be able to fix in about a hour. Flywheel key junk, replace. Carb is where your bigger problem lies, but the fix is not that hard. I use the following procedure every day at work. You will need to purchase kit number 631021B and a new gasket between the carb and manifold or manifold and block (where ever you remove the carb). Follow the procedure and replace the key and you should be ready to go.

Needle and seat replacement

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.

bertsmobile1 said:

It is best to use an inline plug tester.
I use the neon tube kink cause these old eyes aint as sharp as they used to be.
Check for a spark with the plug in the cylinder and again with the plug out & earthed against the cases.

I have a "genuine rebuilt Stihl 070 " in the workshop right now ( cheap Chineese fake ) which will not spark when the plug is in the cylinder.
The customer is about to send me the third replacement to see if we can get it to work.
I no longer fix fakes unless the customer supplies the parts.

Click to expand...

The inline blink light testers are fine, but need to be used with caution because they will give a false positive.

I do have the variable gap testers as well, but the neon tube is the quickest & easiest to use.
Don't think there have been false positives although I do know it just tells me a power pulse went through the tester and does not mean a spark happened at the plug

Thanks for all the help everyone.

I got lazy and ordered a carb for $14. Problem solved, it no longer shuts off.

But I have a new problem. It has no balls whatsoever. The engine bogs down as soon as I apply load (thick grass). I have to mow super slow for it to stay running, though it does start right back up unlike before. I posted a short video and a picture of the spark plug right afterward:



I have tried raising the idle by turning one of the screws on the carb (on the rabbit/turtle bracket) and the bolt underneath the new carb's bowl. No matter how high the idle is the engine bogs down hard when I go over thick grass.
I also tried swapping the spark plug with a known good one and observed no change.

I personally think the problem is ignition timing related, I think it's just not far enough advanced. I suspect this because I did remove the flywheel when I replaced the carb to look at the key, which I did NOT replace. Rivets and others: Do you really think the flywheel key really needs to be replaced? I really don't know what a good one looks like.

I personally doubt that it has to do with timing. I wonder if you have the linkage hooked up properly. Engine would not start and running smooth it the timing was off as far as what your description tells me. Take a look at this manual, sections on linkage and setting the governor. If this does not help then you can look into a timing problem.

http://th.manualwebsite.com/pdf/3-11hp_4-cycle_L_head.pdf

Thank you for that resource! I am set for life with that manual :thumbsup:

I did notice the spring going into the carb linkage (to the valve that allows air in) is touching the air filter. It could certainly be overstretched or installed wrong.

I also forgot to mention that I had no clue what I was doing when I was "adjusting the idle" via the carb bowl screw and screws on the rabbit/turtle bracket thing. I just played with them in a way to make the idle high as possible. Just thought I'd throw that out there lol