190c riding mower runs like it is on one cylinder....

[mattbatson]

I watched the video and it's for sure choking to death on too much fuel.. If I was doing this, I would get it running like in the video, and then disconnect the fuel line.. (Or pinch it closed good). Or turn the gas off if it has a valve..

The point would be to see if the engine cleared out and ran smooth for a few moments before it runs out of gas.. If it does then we could maybe know the carb has a jet or something that has fallen out, or something causing it to offer too much fuel.. Float might have a hole or needle leaking..

Last quick guess. Don't rule out the flywheel key if nothing else ever helps or works.. Only a couple of times I've seem this where it shears and slows down the timing so late that the engine barely runs and will mimic being flooded..

I actually thought of flywheel key, and forgot I had taken pictures
I had a question.
where on the flywheel is the key and is there only one?

I took pics...this is just an empty slot...not sure if the key was in there and fell out?


this is another spot on the flywheel that I thought might be the timing key...



and then there is this hole...



I'm assuming one of these is the flyweel key?

 

[mattbatson]

I had the same mower a few years back and had a fuel delivery problem. The hose form the fuel tank would get pinched and prevent the motor from getting the right amount of fuel. Basically the thing would run but had no power. Finally figured it out and found where the hose was being pinched and it worked fine. Might follow that fuel line and see if there are any issues.

I would be really surprised if this was a fuel delivery problem...but what do I know...
but when I pull the fuel line from the fuel pump, fuel just comes gushing out.

I did trace the line back and it doesnt look pinched and there are no wet spots indicating a leak that I can see...
I was going to replace it anyways, just because it is a ten year old mower.

 

[beenthere]

I thought the flywheel key would be the one that alignes the flywheel to the crank shaft, and a key (half moon or square bar) that slides in when the flywheel is slid onto the shaft. Sometimes, in some engines, a backfire will cause the key to shear and not align the two parts, thus the timing gets cockeyed.

 

[DrBill]

Yes Matt, it's what Beenthere is saying... The flywheel key will be under the big nut holding the flywheel onto the crankshaft..

The flywheel has to be mounted in the correct position relative to the crankshaft.. The key is a small square metal piece that half of it fits in a groove cut into the crankshaft, and the other half fits into a slot cut into the flywheel center hole,, thus holding the flywheel in the correct position, then the big nut is tightened that holds it all together.

The process to check it is ;; First the big nut is removed, then a puller is used to remove the flywheel from the engine.. From that point the alignment key will be found and can be observed to see if it's sheared away (broken).

On some engines you can see the square groove in the flywheel and the square groove in the crankshaft as soon as you remove the big nut and any washers. If so,, you can tell if the key is broken right then..

If you can see theses grooves,,, and if they are lined up together, the key is ok,,, if the grooves are not lined up together,,, then the key is broken...

 

[Gator6x4]

If the "Flywheel" key was broken the engine would not start. The engine will reportedly start and run on one cylinder. Look at the flywheel in the photos that were posted. The flywheel to me has the appearance of an engine that has been exposed to the weather from the rust and pitting.

 

[mattbatson]

If the "Flywheel" key was broken the engine would not start. The engine will reportedly start and run on one cylinder. Look at the flywheel in the photos that were posted. The flywheel to me has the appearance of an engine that has been exposed to the weather from the rust and pitting.

yes it will run and start...just very poorly

also, since I've owned the mower it has been kept in a garage. Most of it's life has been spent in central florida.
I know humidity is high there, so maybe this is the reason for the rust.
but it has never seen rain, or snow, or salt...and has always been in a garage.

now, that said, would that rust on the flywheel affect the timing somehow? The coil's look like they time off the flywheel...

but again, when I test spark, the spark is healthy and looks normal.

 

[mattbatson]

Yes Matt, it's what Beenthere is saying... The flywheel key will be under the big nut holding the flywheel onto the crankshaft..

The flywheel has to be mounted in the correct position relative to the crankshaft.. The key is a small square metal piece that half of it fits in a groove cut into the crankshaft, and the other half fits into a slot cut into the flywheel center hole,, thus holding the flywheel in the correct position, then the big nut is tightened that holds it all together.

The process to check it is ;; First the big nut is removed, then a puller is used to remove the flywheel from the engine.. From that point the alignment key will be found and can be observed to see if it's sheared away (broken).

On some engines you can see the square groove in the flywheel and the square groove in the crankshaft as soon as you remove the big nut and any washers. If so,, you can tell if the key is broken right then..

If you can see theses grooves,,, and if they are lined up together, the key is ok,,, if the grooves are not lined up together,,, then the key is broken...

thx beenthere and bill, I will check the key today and see what it looks like...seems easy enough...

 

[DrBill]

Matt,, I would try what I first mentioned first about starting it up and then cut off the fuel supply to see if it ever clears out and runs normally for even a moment before it runs out of gas...

This will tell us something. If it does run ok for the last second or two,,, it would seem like a overly rich situation pointing back to the carb...

It it continues to barely run even down to the last drop of fuel available ,,,, then that's when I would go ahead and check the key....

Yes, the engine will run or will not run with a sheared key... It depends on how much the flywheel slips on the crank when the key breaks... Too much and it will not run,,, or every now and then blow a fireball out of the muffler or the carb with the classic sonic boom I'm sure some readers here have heard before..

BUT,, if the key breaks and the flywheel slips only a little (like 1/8 turn) or less,,,, it will run the way your engine was in that video.... I've seen this twice in my life, and both were Briggs engines with the square cut flywheel key.. (And I think that is what yours uses)

 

[Gator6x4]

yes it will run and start...just very poorly

also, since I've owned the mower it has been kept in a garage. Most of it's life has been spent in central florida.
I know humidity is high there, so maybe this is the reason for the rust.
but it has never seen rain, or snow, or salt...and has always been in a garage.

now, that said, would that rust on the flywheel affect the timing somehow? The coil's look like they time off the flywheel...

but again, when I test spark, the spark is healthy and looks normal.

The coils are actuated by magnets built into the flywheel. You can find the magnets easily with a screw driver. Just rotate the flywheel and slide the screw driver along the flywheel in the area where the coils interface with the flywheel. Use a medium to fine grade sand paper to clean the magnet area of rust. Also place a light coat of oil on the area after sanding and wipe it off. The air gap between the coils is usually 10-12 thousand. A good way to adjust the coil air gap is to loosen the coil and insert the applicable filler gauge and let the magnet pull the coil in and hold it while you tighten the holding screws on the coil. The use of a brass filler gauge makes the extraction of the filler gauge easy after adjusting the coil. A metal one can be used, just harder to get out.

 

[mattbatson]

https://vimeo.com/105262199

made a video.

took some pliers and restricted fuel to carb while it was running...after about 10 seconds or so, it picked up and ran better.

did this multiple times, and even after letting go with the pliers, it would run pretty good for a bit...

so I guess this means I'm pulling the carb apart again doesnt it...

 

[beenthere]

Seems like it was a good test. :thumbsup:

 

[DrBill]

There is something wrong and it's affecting both cylinders. I suppose the carb and manifold might need looking at again.. Whatever this one thing is, it seems to me it's major and should stand out like a sore thumb. Even with your good videos,, it's not ringing a clear bell to me about what it is ?

I guess that's why we have a forum like this,,, to try..

One more thing that I've scratched my head about is safety switches.. Going back years to my motorcycle days (we sold lawn and garden too). We had a mower here and there that had a bad safety switch that would go bad in a way that it would run , but the crossed up signal(I guess) would interrupt the ignition system while running and cause this unanswerable running condition.. In these cases, a spark check always looked good..

Just like the flywheel key info,,, I'm emptying my bucket and mentioning this just to keep it in mind in case the answer never comes up somewhere else..

There is going to be an answer to this somewhere..

Please keep us posted.. I do want to know the answer whenever this is over...

 

[mattbatson]

I will for sure keep plugging away at it, and will definitely give updates as I go and post up the final result (I know that often people ask about problems on here, and do not post up the final solution...and I understand how frustrating that can be)

I will check the safety switch, and plan to replace all fuel line also....and of course pull the carb down...this time though, all the way down.

thx again for all the help

 

[DrBill]

Thanks Matt,,, let us know the good,, and the bad too.. I hope it starts getting better.

 

[pacerron]

When you took the carb apart you said it looked clean so you only replaced some of the stuff.

Did some of the stuff include the needle valves and seats?
Jim Inman on TBN always advised that the tips of the needle valves were rubber and that they get messed up by the gas we get today even if you use an additive.

We have a L120 with over 1000 hours on it. A couple years ago the wife complained that it was running ruff. The paper clip clean out of the gas cap breather hole
worked for a while but would repeat the missing after a half acre or so. I took the cap apart. There is a splash plate under the rubber that has a shaft that rides up and down in the center tube that has the vent hole in top. It seemed to be binding a bit probably from the plastic pin scarring the tube. Rather than buying a new gas cap, I carefully drilled out the shaft hole another 1/32" on my drill press. That corrected the vent sticking problem.

The missing reappeared, always seemed to be on the side the oil filter is on ( the left side, when sitting on the seat).

I was about to get a carb kit and rebuild it, but had read some threads by Western, on TBN, and others about how great Seafoam was at cleaning carbs.
I had never used it before. My old days of using gumout on Holley 4 barrels, as a kid, made me skeptical.
The Seafoam still comes in a metal can so I was a little anxious about using it in a modern carb with plastic and rubber parts... but.
I ran 1 full tank of fuel with 2 oz. per gallon of Seafoam in it. It started running better as the fuel was consumed and was running like a new engine by the time the tank was almost empty.
It has run fine for 2 summers now, about 8 hours per week, with no re-treatment. We do use Stabil in every batch of gas now, but used it most of the time before, and always in the gas that sits in anything over winter.

I have no interest in either of these products. Just something to try if you haven't already, and you know you put your carb back together right the first time, along with putting the linkages back on properly for the choke and governor..

 

[DrBill]

I stopped by my old shop today and I mentioned this situation to them. They are much more into lawn and garden today and they have dealt with a lot of the Briggs twins.

They agreed that yes, they had seen issues like I described on the Briggs twins before. They said because of shop labor rates they had started replacing the carb with a new one rather than the labor cost of trying to fix. (I think they had some prior boomerangs and that caused that decision)

They mentioned plastic parts and o-ring issues around the main jet area at the bottom of the float bowl..

I liked hearing that maybe this had been seen before, but I didn't like hearing about the hard to fix plastic parts carb..

 

[mattbatson]

When you took the carb apart you said it looked clean so you only replaced some of the stuff.

Did some of the stuff include the needle valves and seats?
Jim Inman on TBN always advised that the tips of the needle valves were rubber and that they get messed up by the gas we get today even if you use an additive.

We have a L120 with over 1000 hours on it. A couple years ago the wife complained that it was running ruff. The paper clip clean out of the gas cap breather hole
worked for a while but would repeat the missing after a half acre or so. I took the cap apart. There is a splash plate under the rubber that has a shaft that rides up and down in the center tube that has the vent hole in top. It seemed to be binding a bit probably from the plastic pin scarring the tube. Rather than buying a new gas cap, I carefully drilled out the shaft hole another 1/32" on my drill press. That corrected the vent sticking problem.

The missing reappeared, always seemed to be on the side the oil filter is on ( the left side, when sitting on the seat).

I was about to get a carb kit and rebuild it, but had read some threads by Western, on TBN, and others about how great Seafoam was at cleaning carbs.
I had never used it before. My old days of using gumout on Holley 4 barrels, as a kid, made me skeptical.
The Seafoam still comes in a metal can so I was a little anxious about using it in a modern carb with plastic and rubber parts... but.
I ran 1 full tank of fuel with 2 oz. per gallon of Seafoam in it. It started running better as the fuel was consumed and was running like a new engine by the time the tank was almost empty.
It has run fine for 2 summers now, about 8 hours per week, with no re-treatment. We do use Stabil in every batch of gas now, but used it most of the time before, and always in the gas that sits in anything over winter.

I have no interest in either of these products. Just something to try if you haven't already, and you know you put your carb back together right the first time, along with putting the linkages back on properly for the choke and governor..

I have seafoam, and have used it on my auto's

it is easy and worth a try.
I'll let you know how it goes

 

[mattbatson]

I stopped by my old shop today and I mentioned this situation to them. They are much more into lawn and garden today and they have dealt with a lot of the Briggs twins.

They agreed that yes, they had seen issues like I described on the Briggs twins before. They said because of shop labor rates they had started replacing the carb with a new one rather than the labor cost of trying to fix. (I think they had some prior boomerangs and that caused that decision)

They mentioned plastic parts and o-ring issues around the main jet area at the bottom of the float bowl..

I liked hearing that maybe this had been seen before, but I didn't like hearing about the hard to fix plastic parts carb..

I saw these parts you speak of when disassembling, and they sure looked fine to me...
I"m going to run some seafoam through it, just to see what happens, and if that doesnt work, then I'll take the carb down.

thx again, and I'll update soon

 

[DrBill]

Matt,, this seafoam stuff is a product for erasing gum and restrictions.

You do not have gum or restrictions. You have too much fuel !

Or you have the right amount of fuel, but you don't have the right ignition to burn it..

Seafoam will not fix your issue. Your problem and " fix in a can " are several miles apart at this juncture...

 

[mattbatson]

hey, sorry, been so busy and didnt get a chance to read this before running some seafoam in the mower...
it didnt clear anything up after a few minutes of running, and I just turned it off knowing that wasnt going to work.

You are correct, the carb is already clean and seafoam is not the answer.

I will update in a day or so when I get some work done on it.

thx again