Lawnmower hard cold-start - works fine otherwise. How to fix?

[mazzgolf]

13 minutes ago, hunterbob1 said:

Is the bulb attached by a 3/8 bolt or a with a threaded bolt needle with a spring. By the way what make mower in engine.

Ahh.. you think the primer might have a problem? Didn't think of that.  I'll have to check to see how the bulb is attached. If the primer bulb isn't injecting fuel into the carb, I guess that might explain some things.

The engine is a Tecumseh.

[mazzgolf]

What the primer bulb looks like... I've never attempted to do anything with this - cleaning or disassembling. It's the same as the day I bought it however many years ago. Maybe the techs did something to it when I brought it in for service those few times, but I never did anything to it.

[hunterbob1]

1 minute ago, mazzgolf said:

Ahh.. you think the primer might have a problem? Didn't think of that.  I'll have to check to see how the bulb is attached. If the primer bulb isn't injecting fuel into the carb, I guess that might explain some things.

The engine is a Tecumseh.

YES..... When you depress the bulb it should come out quick to depress again if it's slow the balls bad or you have a restriction in the fuel line going to the carburetor that explains why it would start when you spray starting fluid in the carburetor After 20 years she lost her suck and blow..lol...Good engines always liked them better than the Briggs.

[hunterbob1]

If the primer bulb is working correctly after three or four or five pumps you should feel a resistance where you can't push the bulb in anymore that means it's pushing the gas and the bulb is full.

[Bucndoe]

1 hour ago, mazzgolf said:

I press the bulb anywhere from 3 to 5 times before attempting to pull. After pulling my shoulder out of its socket pulling several times, I repeat the cycle again  After priming/pulling 3 or 4 times, I spritz with the starting fluid and it starts up fine after a couple more pulls.

After the engine is hot, I never have to press the bulb to start. Usually one or at most two pulls (without priming) and it starts right up.

Oh, one only thing I remember now. The reason why I took apart and cleaned the carb last year was the mower was cutting out/shutting off after running only a few minutes. I would get it to start, then it would shut down soon after. When I took the carb off and cleaned it up (and when I say I took the carb off, I only mean I took the bowl off), a lot of gunk got cleaned out of that little hole on the main jet/bowl nut. Cleaned the bowl, too, then put the carb bowl back on and it ran fine (like it is now). But even before that, the hard cold-start was still a problem.

The carb float was operating fine, BTW. I don't see any problems with the float. I did not change the o-ring gasket around the bowl.

This is pretty much how I cleaned it minus the replacement of the gasket: 

 

You did not take the carb apart and clean it properly. You have to get the main jet out and clean all orafices. Tecumsehs are easy to clean. Do it it throughly and replace your primer bulb. I would start with the primer bulb, it sounds as if its starving for fuel when you first try to start it

Edited April 23, 2022 by Bucndoe

[Coyoteslayer]

2 hours ago, Greybeard said:

Carbs wear down over time.  Rebuild it or it may be cheap to get a new carb online.  After 20 years I'd be looking to get a new mower.  Use your man card, now's your chance.

New mower cuts into fishing $$$. Unless the hackers strike your account for fishing supplies!! 

[Bucndoe]

1 hour ago, mazzgolf said:

I press the bulb anywhere from 3 to 5 times before attempting to pull. After pulling my shoulder out of its socket pulling several times, I repeat the cycle again  After priming/pulling 3 or 4 times, I spritz with the starting fluid and it starts up fine after a couple more pulls.

After the engine is hot, I never have to press the bulb to start. Usually one or at most two pulls (without priming) and it starts right up.

Oh, one only thing I remember now. The reason why I took apart and cleaned the carb last year was the mower was cutting out/shutting off after running only a few minutes. I would get it to start, then it would shut down soon after. When I took the carb off and cleaned it up (and when I say I took the carb off, I only mean I took the bowl off), a lot of gunk got cleaned out of that little hole on the main jet/bowl nut. Cleaned the bowl, too, then put the carb bowl back on and it ran fine (like it is now). But even before that, the hard cold-start was still a problem.

The carb float was operating fine, BTW. I don't see any problems with the float. I did not change the o-ring gasket around the bowl.

This is pretty much how I cleaned it minus the replacement of the gasket: 

 

Half ass job. Take the whole thing off and clean it. An air compressor is your friend 

[JimC1965]

Check the torque on the head bolts. Loose head bolts will allow air to enter the combustion chamber diluting the fuel air mixture ratio. This causes a hard cold start because engines need a richer mixture of fuel to air to start then it does to run. once the engine is warm the metal expands and closes the gap between the head, the gasket and the block. Easier to check this first before tearing the carb apart again. Good luck.

[KBfishing]

New carbs are a God sent. When all else fails replace the carburetor. I love people who throw stuff out because it won't start. I swing in and grab it. Either sonic clean the carb or buy a new one and the engine usually fires right up. 

[Roon]

I bought a brand new stihl weed Wacker gave me problems from the rip, after 2 seasons it finally wouldn't do nothing but piss me off.

Went to rymon and sons to get a carb rebuild kit, he said I can sell you a rebuild kit for $28 or a whole new carb for $32. I said sold knock on wood it's been almost 10 years now and she's up and running on the 2nd pull every  time.

Carbonators suck and when they don't they really do. Lol

 

[hunterbob1]

33 minutes ago, KBfishing said:

New carbs are a God sent. When all else fails replace the carburetor. I love people who throw stuff out because it won't start. I swing in and grab it. Either sonic clean the carb or buy a new one and the engine usually fires right up. 

You're a man after my own heart. Can't count enough how many times I scored curbside pickup knuckleheads throwing things out. Won't work grab the plastic go buy a new one. Got a $500 Dyson vacuum cleaner once I replaced the drive belt for $10.

[hunterbob1]

7 hours ago, JimC1965 said:

Check the torque on the head bolts. Loose head bolts will allow air to enter the combustion chamber diluting the fuel air mixture ratio. This causes a hard cold start because engines need a richer mixture of fuel to air to start then it does to run. once the engine is warm the metal expands and closes the gap between the head, the gasket and the block. Easier to check this first before tearing the carb apart again. Good luck.

120 ft#s

[KBfishing]

1 hour ago, hunterbob1 said:

You're a man after my own heart. Can't count enough how many times I scored curbside pickup knuckleheads throwing things out. Won't work grab the plastic go buy a new one. Got a $500 Dyson vacuum cleaner once I replaced the drive belt for $10.

I picked up a brand new chainsaw someone bought after a hurricane. They tried to change the chain with one that didn't fit. Couldn't figure out why it wouldn't work and threw it out. 

[Greg]

I actually get maybe 2 a year in the shop that complain of no start,,,, they never put fuel in it.

I'd say 80%+ of my repairs are fuel issues.  Going on 4 years I've come across 2 bad spark plugs, and maybe 3 bad coils.

 

On our rental fleet last year and a half we did have 5 oil sensors on honda motors go bad, easy diagnose. Check oil level then unplug sensor wire, yellow one coming out the block and fire it up.

Edited April 24, 2022 by Greg

[Batsto]

Sounds like a old carburetor! You had at for a long time. Deep six it ! Can’t worry about old machines with Turkey season here.