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Hi All,

I am having problems with a Husqvarna LC 146S (2016) mower with Briggs and Stratton 550E Series engine (Serial No: 14 1125 51 8372).

The mower tries to start and might run for a couple of seconds on idle (low revs) and cut out sometimes with a backfire. The last thing I did was check the valve clearance and set to 0.15mm (6/1000 inch) as recommend on YT video. The mower will not fire now that I have changed the clearances. I am at a loss not on what else to do as I have tried everything I found through watching repair videos on YT.

Here is what I tried so far in order:

1. Removed carb and cleaned jets.
2. Removed spark plug and checked for ignition spark (ok)
3. Cleaned around the kill switch and checked for continuity. Kill switch appears to be working as no spark on plug when switch in closed position.
4. Adjusted gap between flywheel and coil which was rubbing in spots.
5. Checked oil leavl and noticed it was over filled. Took some oil out of engine.
5. Double checked the carb to ensure jets are clean
6. Removed flywheel and checked the key/pin was ok.
7. Checked compression by pulling blade in clockwise direction. It doesnt spin freely and does bounce back at certain parts of the cycle. I can hear compressed air been expelled through the air filer which is currently removed.

At this point the mower was trying to start once every 5 - 10 pulls. It might run on very low revs for 1 - 3 seconds and cut out. Poured petrol directly into spark plug hole to see if it might help but didnt make much difference. Noticed when I removed spark plug it was wet and the fuel was blackish colour. I assume this is remaining oil residue in the engine from over filling.

8. Set valve clearances to 0.15mm. I checked before adjusting and 0.15mm gauge was very tight. It was probably set to 0.1mm previously on the exhaust (top valve) and inlet valve (bottom) had wider gap.

Mower doesn't try to start now. It might give a small backfire after pulling cord.

i am at a loss what else to try. The only other thing I can think about is the automatic choke not working. The spring and cable are all connected and it moves freely.

Any help would be appreciated.

Lets back up and remove the spark plug and the valve cover. Rotate the flywheel until the piston is at the top of the stroke by either viewing with a light, or by putting a pencil in the spark plug hole, Make sure both valves are closed. If one is open rotate the flywheel one complete revolution. After both valves are closed then rotate the flywheel just slightly clockwise to move the piston down about 1/4 inch, and then check and set the valve clearances.

Thanks for reply.

I checked the valve clearance using the method you described and still no joy. I posted video here of trying to start it. It almost ran one time.
I'm wondering if I am using the correct valve clearance as it was slightly better before I adjusted them.

One other thing - are the pins that hold the valve in place meant to be loose when pistol is in top position?

What pins are you talking about being loose at TDC, Are you talking about the push rods or the valves stem itself, or the rocker arms being loose.

Looks like valve clearances are .004-.006 for both valves. Air gap on the ignition coil is .006-.014, and the spark plug gap is .020. How fresh is the fuel that you are using. The new Briggs OHV push engines are very picky when it comes to fuel quality.

When you cleaned the carb, did you remove the jet assembly (while part you see when you remove the float bowl)? There are two jets in this assembly and they love to plug up when fuel is left in the float bowl for more than 30 days.

ILENGINE said:

What pins are you talking about being loose at TDC, Are you talking about the push rods or the valves stem itself, or the rocker arms being loose.

Looks like valve clearances are .004-.006 for both valves. Air gap on the ignition coil is .006-.014, and the spark plug gap is .020. How fresh is the fuel that you are using. The new Briggs OHV push engines are very picky when it comes to fuel quality.

Click to expand...

I was talking about the push rods (opposite the valve) and rocker arm. Looking at other videos this seems to be the norn where you can move the rocker arm about.

Valve clearance .004-.006. I assume that is in inch. 0.006 inch = .0.15mm by my calculations.

I used a business card to adjust the coil but will reset that tomorrow using gauge.

Fuel was bought a few weeks ago so should be ok.

Rivets said:

When you cleaned the carb, did you remove the jet assembly (while part you see when you remove the float bowl)? There are two jets in this assembly and they love to plug up when fuel is left in the float bowl for more than 30 days.

Click to expand...

Yes I removed the white plastic part with the jets and split that into two parts also. I could see through both jets and put wire through just to be sure. I used some WD40 for blowing through. There is another part that looks like a jet on the assembley but that appears to be blocked off.

Ive seen another video where they drilled out the jet to improve fuel flow.

How do I test the automatic choke to make sure it is working?

I assume the choke is in open position when first started and closes as engine warms up?

It looked like you were pressing a primer bulb in the center of the air cleaner in your video. If true then you don't have a choke.

I happen to have one of those carbs at home and just took it apart. The white jet assembly is not designed to come apart. The horizontal jet is your main jet and the vertical one is your Venturi nozzle. If you split the assembly into two pieces you probably broke the integrity of the assembly which is why it is not working. As IL said if you are priming there is no choke.

Yes it has a primer bulb. Its the automatic throttle I guess. Should this be fully open or closed on start up?

Rivets said:

If you split the assembly into two pieces you probably broke the integrity of the assembly which is why it is not working.

Click to expand...

Yikes! I followed this video and he split the jet assembly

My jet assembly has the bottom part with O ring as circled below is blocked. It appears to be a be a brass stopper/plug.

Yes, I understand. To tell you the truth I don’t know what that part of the assembly is for. Next time I get a really bad one I’m going to have to do some surgery and see how this assembly works. 90%of the time I find the main jet plugged on this assembly. After ultrasound cleaning and making sure both the main jet and nozzle jet are open, I reassemble and the unit runs properly. The other 10% I replaced the carb.

Thanks for replies. I took the carb out again and noticed the jet I circled above is actually open. Its a very small jet. Anyhow I put everything back and still no joy. I'm thinking to change the carb now. Has there ever been a case where the carb/jets look perfectly fine but engine only runs when they were changed. Should I get the jet assembly or whole new carb unit?

Are you a betting man? How’s your track record on this unit so far? Ask yourself this before purchasing either. If I buy the jet assembly only what do I do if it does not work? Your decision.

Replace the module assembly as you may still not have fully clean. Plus per the date code posted there is a new version for that carburetor. You must which model 09P series you have as there four different new modules. The model and type are engraved on the side of the engine's crankcase.

I like to take a chance. Before I change the carb I just found this video. The choke is open on my carb when engine is cold. Is this the problem?

The item circle is the idle jet and if plugged it is you problem. The previous mention module change was due to this jet clogging. Please refer to the following dealer service bulletin.

DSB-1060

Now after reading this Rivets you will know this module works better.

Yes I know about that bulletin. I have used that assembly with limited success, as I have found the the new jet design still clogs, especially when our reformulated gas is allowed to sit in the carb over the winter. I personally would like to see a fuel drain on this carb. It would solve a lot of problems if used properly.

@StarTech,

Thanks for info. I looks like I can just change the jet assembly. I looked up the part number but it doesn't match with the numbers on the service bulletin.

My engine model number is: 09P702 0142 H1

Well it does have a drain; just many people don't know it is there. Just need hex bit to get it out. The problem there is no fuel shut off valve so you end up draining the whole fuel tank.

Tried removing that “drain” Just broke the body, assumed it was glued or cast in.

Both the old style 591492 and the new style 594632 are removable and are picture below with the plugs removed.

StarTech said:

Well it does have a drain; just many people don't know it is there. Just need hex bit to get it out. The problem there is no fuel shut off valve so you end up draining the whole fuel tank.

Click to expand...

Or it sets so close to the deck that you can't even begin to get a hex wrench in the hole.

It called modifying the hex wrench. When I work SRC we had one place on a forms burster that a standard hex wrench would fit we cut half of short side off to fit in the hole where we had to make the adjustment for 8 lbs of pressure between the feed rollers.

Out of curosity, do any of you fit a tap to the fuel line when you service the mower ?
I was taught to do that when I took over the business and do it as an SOP.
About 1/3 of my customers actually do shut off the fuel after every use and run the engine dry .

I personally feel it is a waste of time and money. Most of the time it is a bandaid and gives the customer a false sense of security. Don’t do it unless the customer asks for it.

I've just joined up to add to this thread.
Old Sanli mower, with exactly the same symptoms. Starts on full choke, revs, then dies.
Have done all of the checks, cleaned out carb, new plug, etc. No change.
Stripped the motor down to basics, just to check for internal wear and see if the governor teeth are still intact, no problems noted.
Replaced carb with new, no difference.
Mutimetered the coil, all ok. BUT remembered that from a previous problem, the low voltage from a multimeter won't show up any short circuits which cut the spark at higher voltages.
Replaced the coil, runs like a dream now.

As it was,a dead coil or burnt exhaust valve were the only two problems left that were possible culprits.
But turning it over by hand showed compression was fine.

Location: Adelaide, South Australia.
Sanli is a Chinese brand, engine is some Honda clone I believe. Around a quarter of the price of a genuine Honda mower. Great for cheapskates such as myself!
Not popular/available in the states? Not represented on your list of makes.

dhes said:

How do I test the automatic choke to make sure it is working?

I assume the choke is in open position when first started and closes as engine warms up?

Click to expand...

The opposite happens with chokes, actually. The choke plate is 'closed' and blocks most air flow when off, then opens to let air in when warm. This engine does not have a choke though. I worked on a couple of these recently. Luckily for me the problem was only the jets were plugged, and I used a sewing needle to clean them. If the fuel is good. I split the plastic white thing in one carefully, and it went back together and worked fine. It is strange that you are having this problem. The carb is still suspect. When I was putting one of mine back together, a plastic cylinder shaped object that goes down the throat of the carb came loose, and I had to re-seat it. If you have found any such piece, check to make sure it is in place. Otherwise, if you have access to a known-good carburetor, check it with that.

Ron_AU said:

I've just joined up to add to this thread.
Old Sanli mower, with exactly the same symptoms. Starts on full choke, revs, then dies.
Have done all of the checks, cleaned out carb, new plug, etc. No change.
Stripped the motor down to basics, just to check for internal wear and see if the governor teeth are still intact, no problems noted.
Replaced carb with new, no difference.
Mutimetered the coil, all ok. BUT remembered that from a previous problem, the low voltage from a multimeter won't show up any short circuits which cut the spark at higher voltages.
Replaced the coil, runs like a dream now.

As it was,a dead coil or burnt exhaust valve were the only two problems left that were possible culprits.
But turning it over by hand showed compression was fine.

Location: Adelaide, South Australia.
Sanli is a Chinese brand, engine is some Honda clone I believe. Around a quarter of the price of a genuine Honda mower. Great for cheapskates such as myself!
Not popular/available in the states? Not represented on your list of makes.

Click to expand...

Ron.

Welcome to the forum.
IF you have a problem with your Sanli it goes in either the Other Brands or Small Engine & Mower Repair with he latter having the most threads .
Sanli makes a lot of mowers for other brands so photos will help the USA members to identify a similar USA branded mower.
Please try to refrain from tacking a differernt problem on the bottom of an existing thread it just gets people confused ,
The techs all use the unread posts search so will see it but some will leave unknown brands for a few days to see if there is some one more familiar with that brand.
If you get no reply after a few days then reply to your own post with a line like "any takers " etc

TylerFrankel1 said:

The opposite happens with chokes, actually. The choke plate is 'closed' and blocks most air flow when off, then opens to let air in when warm.

Click to expand...

Sorry i got that the wrong way around. I opened up the carb and confirmed the throttle/choke plate is fully open on startup from cold. I checked that the lever arm was not blocked but that seems fine. I used a block of wood (picture2) to close the throttle and tried to start but didnt make any difference. Can someone confirm what position the throttle should be in on these Briggs 550E engines when starting from cold? It doesn't seem right that the throttle stays open at start up.

Ron_AU said:

Replaced the coil, runs like a dream now.

Click to expand...

Is there any test I can do to confirm it might be a coil issue. Could I remove the blade and spark plug and then attach a drill to the fly wheel and give it a spin. Should I see a relatively constant voltage on the meter?

TylerFrankel1 said:

The carb is still suspect. When I was putting one of mine back together, a plastic cylinder shaped object that goes down the throat of the carb came loose, and I had to re-seat it. If you have found any such piece, check to make sure it is in place. Otherwise, if you have access to a known-good carburetor, check it with that.

Click to expand...

I have seen that on another YT video where that piece popped out. The main jet goes through it into the carb cylinder. Mine seems to be intact as you can see in picture 1 above. You can see the top of the jet (white bit sticking up) behind it.

I looked up the price of a new carb and would like to rule out all other possibilities before shelling out on something that may not be the problem.

First, if you have to prime the unit there is no choke, don’t use that term as it gets confusing. Second, the throttle should be wide open at startup. The governor will close the throttle when the engine starts. Third, you can remove the spark plug and hold it against the cylinder head while having an assistant pull the starter rope. Best to do this in a dark area, as you are looking for a good spark. SAFETY NOTE. Hold the plug, with the wire attached, with a good pair of insulated pliers. If the coil is good you could get a rude awaking. Also, your assistant should pull the brake bail back, just like when you are cutting. Remember you now have a spinning blade under the deck.

bertsmobile1 said:

Ron.

Welcome to the forum.
IF you have a problem with your Sanli it goes in either the Other Brands or Small Engine & Mower Repair with he latter having the most threads .
Sanli makes a lot of mowers for other brands so photos will help the USA members to identify a similar USA branded mower.
Please try to refrain from tacking a differernt problem on the bottom of an existing thread it just gets people confused ,
The techs all use the unread posts search so will see it but some will leave unknown brands for a few days to see if there is some one more familiar with that brand.
If you get no reply after a few days then reply to your own post with a line like "any takers " etc

Click to expand...

Sure. No problem with my mower, all fixed. And I wasn't looking for help with a problem.
The general principle that I brought up applies to fault finding any small 4 stroke engine. If you have checked all the usual causes of not starting or running right, the coil is the next - and possibly last - obvious suspect. Brand of engine doesn't matter so much.

dhes said:

Is there any test I can do to confirm it might be a coil issue.

Click to expand...

Not without the right test equipment, no.
Try taking the plug out, opening the gap to twice normal, and see if you get a spark spinning up the engine with the plug resting outside the engine on some of the mower metal.
I got a spark from the original coil with the plug out of the engine with the standard gap.
Doesn't mean it fires while under stress inside the engine though. Heat, vibration, arcing across the high tension side of the coil internally, and the engine just cuts out after running for a few seconds, or just refuses to fire up at all.

Anyhow, if you are sure everything is ok - compression, fuel, air - it's the last thing to try. Or put it out on the curb. For me with my old mower, that was a 50:50 line call. Glad I went to the new coil though.

*UPDATE*

It's running!!! Well sort off...

I swapped out the spark plug and disconnected the kill switch and got it running for about 10 seconds. It was throwing out quite a bit of black smoke. It cut out and I couldn't get it running again after this and wasnt sure if changing the spark plug or disconnecting the kill switch was the trigger.

So I pulled out the new spark plug and it was wet with with quite a bit of oil. In one of my previous posts I mentioned that the engine was over filled with oil which I removed. I guess this is the remains of the oil overfill.

I cleaned off new spark plug and sprayed carb cleaner directly into the spark plug hole. It still wouldnt start. I then removed new spark plug which again was covered with oily fuel and put back in the old plug which was clean. I connected the kill switch and it fired on the second pull. It's still trhowing out quite a bit of black smoke. It's not running smoothly as seen in video below.

I also pumped the primer bulb when running to see if the revs would increase but it almost cut out.

So I have no idea what was wrong but any suggestion on how to fine tune it from here would be appreciated.

Sounds to me like your cylinder is flooded, caused by the oil overfill. Maybe I shouldn’t do this, but I’m assuming that you drained the old oil and put in fresh. I would remove the plug and pull the engine over 15 times toget as much fuel/oil mixture out of the cylinder. Clean your best plug with carb cleaner and install. Start the engine and let it run. It will probably throw a lot of smoke out the muffler, the muffler may even drip oil, which should clear up in about 5 minutes. You have a lot of fuel and oil to get out of the cylinder, be patient. Do this in a wide open area and you won’t have mosquitoes until May.

Thanks I will try that. I didn't drain all the old oil out at the time. I just took enough out to bring it down to proper level. Will change it now that i know the mower is worth saving.

I took out the plug and pulled the engine over about 15 times. It only really splurted on the first pull and not much more came out after that. I then got the engine up and running again after a bit of effort with cleaning and changing plugs. It was not running smooth and still throwing out black smoke with fairly strong smell of fuel. After about 5 mins it then started running smooth for about 10 seconds and cut out. I checked the fuel tank which had emptied. After a fuel refill and cleaning/changing plugs I got it running again but still not running smooth. Some white gunk started coming out of the air port on the carb as shown in pic below. I assume this is water in the engine? (This mower has been sitting outside all winter).

Anyhow I have the mower draining oil at the moment. Do I need to take off the flywheel and clean the white gunk out of the air port. I have sprayed carb cleaner into it and left the mower on its side to drain over night.

I wish you would have changed the oil before trying to run the engine. Because the oil in the engine was contaminated with fuel, you didn’t have a lot of protection. The engine was running rough because of the contaminated oil, it should clear up and run smooth after it gets fresh fuel and oil, but this may take 30 minutes. I see no reason to remove the flywheel and try to clean the white gunk. Wipe off what you see and run the unit. This to will need to work its way out of the system.

Ok I changed the oil and got fresh fuel. The engine took a bit of effort to get started and it ran it for about 7 - 8 mins before running out of fuel. I noticed when I was filling it that fuel was running out of the carb so Im guessing the float is stuck or not sealing correctly. Anyhow i refilled and it fired first time and ran for another 10 mins. The engine is still blowing black smoke but feels a bit smoother to pull start. The video below shows it running but not easy to see black smoke. After 40 seconds of the video you can hear where the engine starts running a bit smoother before running out of fuel. I'm thinking that too much fuel is going to the engine. Would this be a reason for black smoke and running rough?

What you described means the float needle is not closing the seat, producing a rich mixture. Time to rebuild the carb with a new needle and seat. If you don’t have experience with carb rebuilding, this is not the carb you want to make your first attempt.

Honestly, I am happy to give it a go. This is my friends old mower and I only took it on to learn how these engines work. He has bought himself a new mower and the honda in our garage runs like new after 20 years. We are going to sell this on either as running or for spares/repairs. Any advice on how to rebuild the carb with needle and seat would be appreciated. I have time but not worth spending money on a new carb for something that will be sold for 100 euro or less

The price for a new carb is less than $50.00 US. Might be you best bet.

Rivets said:

The price for a new carb is less than $50.00 US. Might be you best bet.

Click to expand...

If I was going to keep the mower it might be worst investing in a new carb. I will try clean the needle and if that doesnt work it will be sold for spares or repair. Appreciate your help all the same and learned a bit about small engines.

Rivets: What you described means the float needle is not closing the seat, producing a rich mixture.

Click to expand...

This indeed was the problem. The pin holding in the float bowl was not sitting correctly in the clips allowing the float bowl to drop as shown in pics below. When I pushed the pin down into the clips it would work correctly but then when I take pressure off the pin the bowl would drop. Lucky enough I found a second hand carb locally so replaced the whole carb and mower now runs perfect.