Lawn mower will not start.. help!

Jul 19th, 2021 12:54 pm

#1

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 12:54 pm

Working until yesterday. Attempted to start and no go. Looking at the spark plug there is heavy carbon build up meaning black. The plug is only a year old.

Steps taken:
- drained fuel and blew line
- changed oil
- new air filter
- last year I ran stuff through it like sea foam to clean carburetor
- new spark plug
- used a spark tester. there appears to be spark but unsure if strong enough
- removed air filter and sprayed starter liquid… doesn’t start
- spark plug wire connected and fresh fuel when attempting to start
- clean underneath and nothing seems to be impeding with the blade

Done everything in my capability with no luck. Any advice? It’s a Craftsman w/Briggs and Stratton 6.75hp engine. There is no manual choke or primer bulb. It’s an easy start type.

Guessing, but I think I bought it in 2006 and it’s been a workhorse. First problem I’ve encountered.

Jul 19th, 2021 1:16 pm

#2

Anikiri: Deal Guru; May 1, 2012; 10484 posts; 11241 upvotes; Toronto

Jul 19th, 2021 1:16 pm

You have to take off the carb and clean it with carb cleaner and a small metal wire.

Running seafoam from the fuel tank does not help enough.

1. Drop the carb, clean the bowl. Remember not to lose any of the pieces.
2. Drop the injector pin, clean the pin.
3. Use a metal wire to clean every hole you can find.
4. Liberally spray carb cleaner everywhere.
5. Dry off well.

Alternatively, u can turn your mower on the side, and manually spin the blade until you've repositioned the pistons. Sometimes this can help.

+1

Jul 19th, 2021 1:21 pm

#3

fordmaple: Deal Addict; Nov 6, 2014; 1294 posts; 2350 upvotes; 0 downvotes (Maple,O…

Jul 19th, 2021 1:21 pm

I think I have the exact same one and experienced a similar issue. Use carb cleaner or brake cleaner with decent pressure to clean out the carb. Be generous. When I did that it helped but still wouldn't start. I then used the cleaner to clean all of the wire linkages that were gummed/gunked up. Once I cleaned *ALL* of the linkages and they were moving freely it started up. Give it a shot.

Agreed, work horse lawnmower...except the wheels are crap.

Jul 19th, 2021 1:37 pm

#4

grumble: Deal Addict; Mar 22, 2017; 2757 posts; 3830 upvotes; West GTA

Jul 19th, 2021 1:37 pm

Yeah, clean the carb and you'll be in okay shape. In the future, run premium gas only and add in a bit of seafoam preventatively to keep the fuel fresh and to reduce gunking up.

+1

Jul 19th, 2021 1:39 pm

#5

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 1:39 pm

Thanks for the tips.

Agree the wheels are crap.

Wouldn’t using starter fluid / quick start fluid bypass the carburetor and get the lawn mower to start? It would die quickly after the starter fluid runs out unless you keep spraying it in.

I have ordered the overhaul kit and plan non cleaning the carburetor. Just thought there may be some other issue like a weak spark needing a new ignition coil perhaps.

Have always used premium fuel with no ethanol.

Last edited by Bidjaan on Jul 19th, 2021 1:58 pm, edited 1 time in total.

Jul 19th, 2021 1:52 pm

#6

BDSL: Deal Addict; Sep 22, 2009; 3272 posts; 2152 upvotes; Markham

Jul 19th, 2021 1:52 pm

Anything blocking the air way?
How old is the fuel? Is there blockage in the fuel line?

Jul 19th, 2021 2:01 pm

#7

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 2:01 pm

BDSL wrote: ↑ Anything blocking the air way?
How old is the fuel? Is there blockage in the fuel line?

Air filter is removed. No fuel king blockage. Fuel is only 2 weeks old.

As mentioned using quick start sprayed in from carb area. This should at least get it to fire up then die.

When turn the mower blade manually, it doesn’t spin very smooth and I hear kind of a rubbing. Not sure if this is normal.

Trying to determine if the engine is done

Jul 19th, 2021 2:22 pm

#8

BDSL: Deal Addict; Sep 22, 2009; 3272 posts; 2152 upvotes; Markham

Jul 19th, 2021 2:22 pm

Bidjaan wrote: ↑ When turn the mower blade manually, it doesn’t spin very smooth and I hear kind of a rubbing. Not sure if this is normal.

Turning engine by hand is never "smooth"....you are compressing the air in the cylinder.

Jul 19th, 2021 2:40 pm

#9

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 2:40 pm

BDSL wrote: ↑ Turning engine by hand is never "smooth"....you are compressing the air in the cylinder.

I do hear that.

Cleaning the carburetor will be done, but I don’t think that’s what’s keeping it from starting. Compression or spark????

Jul 19th, 2021 2:44 pm

#10

cheapmeister: Deal Guru; Feb 23, 2008; 12741 posts; 1657 upvotes; Brampton

Jul 19th, 2021 2:44 pm

You need 3 things: air, fuel, spark. Likely its not getting fuel, try cleaning the carb.

Lets Go Blue Jays!!!

Jul 19th, 2021 3:03 pm

#11

BDSL: Deal Addict; Sep 22, 2009; 3272 posts; 2152 upvotes; Markham

Jul 19th, 2021 3:03 pm

Bidjaan wrote: ↑ I do hear that.

Cleaning the carburetor will be done, but I don’t think that’s what’s keeping it from starting. Compression or spark????

It is hard to diagnose over the internet. It could be something simple like the push/pull cable on your handle bar.
You will have look at each individual component.

Jul 19th, 2021 3:14 pm

#12

l69norm: Deal Expert; Jun 12, 2007; 19608 posts; 6375 upvotes; London

Jul 19th, 2021 3:14 pm

Bidjaan wrote: ↑ Air filter is removed. No fuel king blockage. Fuel is only 2 weeks old.

As mentioned using quick start sprayed in from carb area. This should at least get it to fire up then die.

When turn the mower blade manually, it doesn’t spin very smooth and I hear kind of a rubbing. Not sure if this is normal.

Trying to determine if the engine is done

When turning manually, is the blade brake still engaged ? Take the spark plug out, have someone hold the bail for the brake blade, then try turning by hand

You already sprayed cleaner down the carb and it did run ? (or do you mean you still need to test this?)

Jul 19th, 2021 4:30 pm

#13

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 4:30 pm

The carb overhaul kit is arriving Wed. And I will get more carb cleaner from princess auto.

Understand it needs fuel and air, but by removing the air filter and spraying quick start fluid you are providing both of those directly, and essentially bypassing the carburetor for the start and until the quick start fluid is consumed which is only a few seconds. However, it is not
starting doing this.

I put an inline spark tester and can see the orange light flicker. Also feel the charge on the spark plug cap. It’s beyond me if the spark is strong enough so could be the ignition coil.

Going to have to send it in for service. Will clean the carburetor and replace gaskets etc so they don’t charge me for that maintenance as part of their own troubleshooting and repair.

Jul 19th, 2021 4:41 pm

#14

KevinM56081: Banned; Jun 4, 2020; 1634 posts; 1744 upvotes; Clarington, ON

Jul 19th, 2021 4:41 pm

Bidjaan wrote: ↑ The carb overhaul kit is arriving Wed. And I will get more carb cleaner from princess auto.

I think it's awesome that you're giving the rebuild a go. From experience, a replacement carb is not much difference in price (and I've even found them cheaper on occasion).

+2

Jul 19th, 2021 4:45 pm

#15

deals4realz: Member; Nov 27, 2020; 284 posts; 566 upvotes

Jul 19th, 2021 4:45 pm

Wow! So many enthusiastically helpful posts. Must have a lot of small engine guys on here. Makes me want to go out and buy a broken mower just to get in on the fun!

Jul 19th, 2021 4:46 pm

#16

l69norm: Deal Expert; Jun 12, 2007; 19608 posts; 6375 upvotes; London

Jul 19th, 2021 4:46 pm

Bidjaan wrote: ↑ ..... However, it is not starting doing this. ....
..

Then it's likely not a carb problem.

The last time you used the machine, did you hit anything with the blade ?

Jul 19th, 2021 5:20 pm

#17

Bianco13: Deal Addict; Jan 23, 2015; 1319 posts; 917 upvotes; Woodbridge, ON

Jul 19th, 2021 5:20 pm

It could be as simple as removing the "brass nut" at the bottom of the carburetor bowl and cleaning the little hole in it.

Jul 19th, 2021 5:39 pm

#18

Bidjaan [OP]: Deal Addict; Sep 7, 2017; 1114 posts; 1120 upvotes

Jul 19th, 2021 5:39 pm

I removed the carb out of curiosity. It was super clean inside. I cleaned it anyways and checked every hole. Sure it’s not the carb.

I didn’t hit anything or hear any funny noises. However in removing the carb, I noticed a piece is loose. Believe it had to do with the choke and possibly this has broke somewhere inside. Seemed unusually loose.

Appreciate all the help and suggestions. Will send it to the small engine repair shop and see what they come up with. Will post a conclusion. I am hoping it’s something simple. After 15 years it’s probably not a bad thing to have it checked out top to bottom for $36.

Jul 19th, 2021 5:55 pm

#19

budwizestest: Sr. Member; Oct 14, 2010; 885 posts; 1026 upvotes; Toronto

Jul 19th, 2021 5:55 pm

Bidjaan wrote: ↑ I removed the carb out of curiosity. It was super clean inside. I cleaned it anyways and checked every hole. Sure it’s not the carb.

I didn’t hit anything or hear any funny noises. However in removing the carb, I noticed a piece is loose. Believe it had to do with the choke and possibly this has broke somewhere inside. Seemed unusually loose.

Appreciate all the help and suggestions. Will send it to the small engine repair shop and see what they come up with. Will post a conclusion. I am hoping it’s something simple. After 15 years it’s probably not a bad thing to have it checked out top to bottom for $36.

15 years, good for you!

I am on the 8th and no trouble so far, and I don't do any maintenance on it except feeding it 0 ethanol gas and throwing in some Seafoam at the start of the season in the tank....

That is why I don't understand why anyone would go electric/battery.

Jul 19th, 2021 7:20 pm

#20

BDSL: Deal Addict; Sep 22, 2009; 3272 posts; 2152 upvotes; Markham

Jul 19th, 2021 7:20 pm

I am surprise the electric mower lovers haven't came in here yet preaching about their 30 year problem free electric mowers...
It always happens in the Automotive section....

+1