Lawnmore cuts out after 2 seconds...

[accent2012]

Friend has a lawnmower she is trying to get to work again. She hasn't used it because she always had someone do her yard work, but now she can't afford it, so she is getting back into doing it herself.

I believe the mower is a brig straton (sp?) engine. Anyway, I checked the spark plug and while it looks dirty, it doesn't look like it's fouled up or crusted over. Either way the plug will get changed.

History:
This mower sat unused for at least a year. Prior to this, the fuel was drained and the oil changed. I have yet to see the condition of the air filter, but that doesn't matter as that will be replaced once we can figure out what is making the engine sputter out.

My guess is something has gummed up either the carburetor or something within the fuel tank. What should I expect if the mower sat unused with an empty or nearly empty tank?

We tried spraying WD 40 in the crank through the spark plug but that didn't help.

Any ideas?

 

[Donald]

Sounds like a carb problem. The carb need to come off and looked at. Maybe just squirt some carb cleaner down the main jet and then run a drill bit into the jet with the bit in your fingers, not a drill. Squirt some carb cleaner into the float needle valve. Run a QT of alcohol into the fuel tank and out the fuel line disconnected from the carb.

Choke linkage problem?

 

[accent2012]

I'll double check the choke linkage. She sent me this picture (I'm at work at the moment):

That appears to be the carburetor and the rubber hose with the green clamp is likely the fuel line since the tank is situated above this, and you can see the spark plug on the right.

The carb appears to be clean, but I'm not sure judging by the picture alone. She just told me that she sprayed some carb/maf cleaner into there and now it won't crank at all.

I'll take a crack at it when I get home.

 

[Quest]

it's a LMS (Walbro or clones) sidedraft carb.

Need to first pull off the bowl and check to see if there's debris clogging the jets, orifices, etc. and compress-air blow clear everything before you put it back.

Also: if you are being nice, install a 150micro mesh (red plastic body) gas filter along that 1/4" ID fuel line to keep the dirt from getting into the carb.

Good luck and let us know if you need more help.

Q.

 

[dernp]

There should be a fuel metering valve under the bowl. Take that off then the bowl will come off. Use carb cleaner to clean the metering valve and spray the bowl as well. That should do it.

 

[bepperb]

Has that crankcase breather been hanging loose like that the entire time?

 

[Bud]

I agree with everyone else. Just make sure fuel system is spotless and don't forget to check gas cap vent and fuel suction hose filter usually in fuel tank if you have a filter on the hose. I had trouble once with mine and that small filter ended up being the problem. If the tank was empty for all that time that filter could be gummed up.

 

[jhellwig]

Originally Posted By: bepperb
Has that crankcase breather been hanging loose like that the entire time?


That is where they are supposed to be. They go into the air cleaner housing.

You aren't going to get it to attempt to start now that the gasket to the air cleaner housing is broke. The channels to the primer bulb are in there. Since it is that far you should just rebuild the carb and replace the primer bulb. Not that expensive and parts are readily available. You can even get the whole carb from amazon for 30 bucks.

That is Briggs quantum style engine. They are hard to kill.

If you get lost as to what goes where or need to figure out what to order go to Briggs website. You can look at the illustrated parts list and get all the part numbers and even order them right there if you want. You will need the model number for the engine. It is located right above the spark plug on the metal shroud.


Oh and if she sprayed so much carb cleaner into the carb that now it won't turn over then you need to take the spark plug out and then turn it over.

If you take the gas line off and take the bolt out of the bowl on the bottom of the carb, spray carb cleaner in the gas line and it comes out the bottom then you are good on that part. If you stick the straw from the can of carb cleaner in a hole on the carb and it shoots out another hole you are good. Lots of holes, check them all.

 

[PhilsSmallEngine]

I would comment on the Briggs Quantum durability, but I've killed one in less than 10 hours so it wouldn't be proper to speak of all of them.

I actually got my old Tecumseh fully unclogged without rebuilding it by pouring a 40:60 mix of Seafoam and gasoline directly into the carburetor and leaving it overnight. I also poured some Seafoam into the gas tank to continue the treatment should what I poured into the carb leak out or evaporate.

10 primes and two pulls later, the engine roared to life. After 20 mins of running, I pulled the main jet and bowl off to inspect. Everything looked brand new (better than when I put it away) and the engine ran very well.

I've been dreading the day I would have to rebuild the carb that I ignored for 25 years, yet I've seemingly averted it for another year. I even bought the rebuild this winter assuming I would need it. The old beast hasn't been running so well in years despite running in sub 50 degree weather.

 

[bubbatime]

I've worked on a ton of these Briggs quantum engines. You can waste your time rebuilding the carburetor with a carb kit ($10-12) plus several hours of your time or just buy a new carburetor. These days I just put a new carburetor on them. Only takes about 4 minutes from start to finish for me to change. They run $25-$30/shipped on eBay.com and Amazon.com. The aftermarket Oregon brand carburetors are a few dollars cheaper than OEM Briggs carburetors and they work just as good. I've used at least 10 of them and they work fine.

FYI, the two carburetor bolts are 3/8 and the air cleaner base uses three 5/16 bolts.

 

[yeehaw1960]

Gas will run out so put a rag under the carb. Loosen the 1/2 inch nut on the bottom of the carb. Put something under the carb to catch the fuel. Be prepared for whatever fits under there not to hold all the gas from the tank. Have a place to dump it out each time it fills up. After the gas all runs out, remove the bowl nut and pull the bowl off. If the bowl doesn't come right off, use a thin screw driver to gentle pry it off. Dump out remaining fuel from bowl and clean out ick. Run a (skinned) bread wrapper through the hole in the top and the two holes at the base of the bowl nut. Spray some carb cleaner inside the carb and up into the carb as best you can. Blow it out with air if you can. Reassemble carb, replace gasket that is broken (or your mower won't prime), gas it up and go. If (after tank is drained) you put a little gas into the tank and let it force the remaining bad gas out of the line before you reassemble, it will help in the long run.

 

[Lubener]

Before you take it apart, take a wrench and tap on the bowl and try it out. Maybe the float hs stuck from sitting.I had gas sitting for a year and had no problems with it.

 

[accent2012]

Thanks for the advice guys. I haven't done what some of you have posted yet. She is going to take it somewhere to get it looked at.

I noticed that with either of the spark plugs, the plug does not make a spark anymore.

I did take the carb out and tried to take the bowl out, but having not read that comment about using the screw driver to pry it off, I left it alone in fear that I wouldn't be able to put it back together. Last thing I wanted to do is make it worse for the lawnmower mechanic.

The choke linkage appeared to be fine.

It's safe to say that the mower now doesn't create a spark at all, and that may be the culprit.

 

[Donald]

Originally Posted By: accent2012
Thanks for the advice guys. I haven't done what some of you have posted yet. She is going to take it somewhere to get it looked at.

I noticed that with either of the spark plugs, the plug does not make a spark anymore.

I did take the carb out and tried to take the bowl out, but having not read that comment about using the screw driver to pry it off, I left it alone in fear that I wouldn't be able to put it back together. Last thing I wanted to do is make it worse for the lawnmower mechanic.

The choke linkage appeared to be fine.

It's safe to say that the mower now doesn't create a spark at all, and that may be the culprit.


If it runs for 2 seconds it has a spark.

 

[Brian123]

Originally Posted By: accent2012
It's safe to say that the mower now doesn't create a spark at all, and that may be the culprit


The Coil is probably bad and it needs to be replaced.

 

[accent2012]

Originally Posted By: Donald
Originally Posted By: accent2012
Thanks for the advice guys. I haven't done what some of you have posted yet. She is going to take it somewhere to get it looked at.

I noticed that with either of the spark plugs, the plug does not make a spark anymore.

I did take the carb out and tried to take the bowl out, but having not read that comment about using the screw driver to pry it off, I left it alone in fear that I wouldn't be able to put it back together. Last thing I wanted to do is make it worse for the lawnmower mechanic.

The choke linkage appeared to be fine.

It's safe to say that the mower now doesn't create a spark at all, and that may be the culprit.


If it runs for 2 seconds it has a spark.


I'm sorry, I meant to say in that post that now it doesn't start at all. This was before I removed the carb.

 

[Nick R]

It's a fuel problem. This is a common issue with these, I've had it with ours several times. Pull the carb bowl off (there is a nut on the bottom), clean the jet using something like techron or starter fluid, rinse the bowl out with techron too. Reassemble, should fire right up.

IMPORTANT: Before doing this, clamp off the fuel line using a pair of vice grips, so when the float falls down, it doesn't drain the tank all over your driveway/yard. Also be careful not to let the float and needle valve fall off, as the needle valve and spring for it are very small and will easily be lost.

 

[TFB1]

Originally Posted By: Brian123
Originally Posted By: accent2012
It's safe to say that the mower now doesn't create a spark at all, and that may be the culprit


The Coil is probably bad and it needs to be replaced.


Not likely if it runs for two seconds as stated, 99.99999% that's a fuel problem...

 

[bubbatime]

Agree fuel problem. Coils will sometimes die once the engine reaches full temperature. Never seen one die out after 3 seconds. This is a very common, and very easy fuel delivery problem to fix on these engines.

Post the engine numbers (model/type/code). They can be found on the horizontal metal plate directly above the muffler. Can help you find the correct kit or carburetor. They make 2 different carburetors for this engine, one for primer bulb and one for auto choke.

Watch this video, very easy to clean/replace the carburetor.
https://www.youtube.com/watch?v=Dq-EKfAjvLU

If you take it to the shop, it will cost $70-100 to fix. Or replace the carburetor yourself in 5 minutes for about $28. Easy choice ....

 

[accent2012]

Well she took it to a lawn mower mechanic.

He determined that it was ethanol build up in the bowl which I couldn't take apart before. Mower runs fine now.

I really didn't want to dive too deep into it in case I took something apart that I couldn't put back together. I didn't want to inadvertently break something.