Gas mower problem

[lew]

Morning boyz, I've got a problem with a gas mower and for the life of me I can't get it working properly.

 

It's a 2 year old push mower with a 148 cc 4 stroke Briggs & Stratton motor.

 

When it was stored away last fall I stabilized the gas, then ran the engine dry and changed the oil. I fired it up yesterday for the 1st time this season and it started on the 1st pull like it always does and ran perfectly for 10 seconds then the problem started.

 

It runs at full speed for 1 second then the revs drop right down for a second then back up to full speed again, then just keeps repeating this over and over...up then down, then up and then down again. Every time the revs increase a puff of blue smoke comes out the exhaust too.

 

The air filter is clean, the spark plug is clean and I ran SeaFoam thru through the motor but it still didn't make a difference. I looked for a gas filter but there doesn't appear to be one.

 

I've been scouring the internet and the Briggs & Stratton websight and everything tells me to adjust the carburator settings, but this doesn't even look like a normal carb and there are NO adjustment screws that I can find.

 

It's only a cheap mower that I use for spots I can't get the riding mower into and can replace it brand new for $160 so there's not much sense in taking it to the repair shop but thought someone here may have an idea.

 

Anybody have any thoughts ??

 

 

This is the air box with foam filter...clean

 

 

Air box removed looking down into carburator

 

 

No adjustments anywhere....that I can find

 

[Sandbag]

Lew.....I had the same problem with my mower earlier this season. I removed the carb (which looks exactly like yours and all plastic). I sprayed carb cleaner through all of the orifaces and jets to clean them out. It was fine after that. I suspect a little bit of dirt in one of your jets as well too. Ive found that it doesnt take much to get some dust into the fuel and carb, especially if the mower is used in areas with bare patches of dirt. Good luck and let us know how it goes.

 

 

PS...i took a quick picture of the springs etc on the carb set-up before i took it apart, but like you say there isnt much adjustment to be done on them nowadays.

 

Cheers

 

Craig

[lew]

Thanks Craig

 

I figured if there was gas residue crud in any of the lines the SeaFoam would clear it but I'll try the carb cleaner too incase it's some dirt in there.

[bushart]

May not help at all---but since my outboard issues---even my lawnmower gets super gas

 

Apparently ethanol has a hunger for some rubber types

[lew]

You could possibly be right Bushart, but I'm old fashioned and use the fuel that's recommended by the manufacturer but with the new ethanol problems it could be worth a try.

 

I do run stabilizer in ALL my motors year round.

 

I just purchased a new Stihl grass trimmer and it calls for hi-test.

Edited May 12, 2012 by lew

[bushart]

I was fortunate Lew when the Mechanic was workin on my outboard---I got to watch and talk with him

 

Before that time--I used reg unleaded with ethanol

 

Anyway with one of my carbs apart--- he showed me the smallest speck of rubber in a port---causing all my headaches

 

hard to believe something so small---almost dust like---could cause so big an issue

 

Super ever since

[Skipper D]

Reving up and down is usely covenner trouble , lift the pull cord cover off by taking out three bolts , check to see if some little critter did'nt make his home in there , check around the fly wheel and the plastic covenner rod to see if a nest is keeping the covenner from working .................

[Terry]

everything built these days is made to handle ethanol including the rubber, so I don't think that is the problem....I would use the grade of fuel they recommend...most likely something blocking a jet

[Skipper D]

many times you'll see grass clippings get built up in there over time Lew , but who knows what it is ...... til ya find it ..lol

[dave524]

Reving up and down is usely covenner trouble , lift the pull cord cover off by taking out three bolts , check to see if some little critter did'nt make his home in there , check around the fly wheel and the plastic covenner rod to see if a nest is keeping the covenner from working .................

 

this has been my experience with the revving up and down.

[bushart]

everything built these days is made to handle ethanol including the rubber, so I don't think that is the problem....I would use the grade of fuel they recommend...most likely something blocking a jet

 

 

I'm not sure what year they started using ethanol proof rubber on items??

 

I talked to an auto mechanic a while back----if anything is 10 yrs or older---maybe an issue

 

like my ob was

[Fisherman]

Lew.....I had the same problem with my mower earlier this season. I removed the carb (which looks exactly like yours and all plastic). I sprayed carb cleaner through all of the orifaces and jets to clean them out. It was fine after that. I suspect a little bit of dirt in one of your jets as well too. Ive found that it doesnt take much to get some dust into the fuel and carb, especially if the mower is used in areas with bare patches of dirt. Good luck and let us know how it goes.

 

What Sandbag said. There's a tiny bit of dirt floating around at/in the jet. You get the initial bit of gas through it, the dirt gets sucked up, clogs the jet, the motor starts to die, the governor pulls on the auto choke lever, gets a bit of gas that way, makes a puff of blue rich smoke, the dirt drops a bit and gets more gas and the process goes over and over.

I call it the auto choke lever, probably called something else though.

Edited May 12, 2012 by Fisherman

[lew]

I pulled the cover off the flywheel and everything is nice and clean in there...no critter nest.

 

Thanks for the suggestion Skipper.

 

I'm heading into town right now to pick up some carb cleaner at NAPA and will be back in an hour and giver a sqirt.

 

I'll post back in awhile with the results.

 

If it doesn't work there'll be a non-working mower for sale in the classfieds....cheap.... while I go buy a new one

[Tybo]

Lew,Try running it with out the air box.

Edited May 12, 2012 by Tybo

[Big Cliff]

Lew, drop it off at my place, I'll have it fixed for you in no time. You have to remove the gas tank (2 bolts and un hook the throttle leaver) to remove the carb. The carb is then held to the tank by 5 screws (phillips). Under the carb is a diaphram and seal that goes between the tank and carb, (I have both here)those diaphrams have a habbit of when dried out loosing their seal on the outside edge. I can do it for you in half an hour NO CHARGE and it would be my pleasure to finally do something for you!

 

313 Snug Harbour Rd.

Lindsay.

 

Cell if you need it 705-928-8899

 

Hwy. 36 South from Bobcayegon to Kennedy Bay Rd. Turn right on Kennedy Bay Rd. To Snug Harbour Rd. (You'll be going down a hill and it will be on your left, the sign is a little hard to see). Left on Snug Harbour Rd. about 3km. to my place. Just let me know when you are coming and I'll try to be here so I can fix it while you wait. If it is during the week I work from 8to5 so you could either drop it off one day and pick it up the next or come by in the evening.

[ketchenany]

Lew, drop it off at my place, I'll have it fixed for you in no time. You have to remove the gas tank (2 bolts and un hook the throttle leaver) to remove the carb. The carb is then held to the tank by 5 screws (phillips). Under the carb is a diaphram and seal that goes between the tank and carb, (I have both here)those diaphrams have a habbit of when dried out loosing their seal on the outside edge. I can do it for you in half an hour NO CHARGE and it would be my pleasure to finally do something for you!

 

313 Snug Harbour Rd.

Lindsay.

 

Cell if you need it 705-928-8899

 

Hwy. 36 South from Bobcayegon to Kennedy Bay Rd. Turn right on Kennedy Bay Rd. To Snug Harbour Rd. (You'll be going down a hill and it will be on your left, the sign is a little hard to see). Left on Snug Harbour Rd. about 3km. to my place. Just let me know when you are coming and I'll try to be here so I can fix it while you wait. If it is during the week I work from 8to5 so you could either drop it off one day and pick it up the next or come by in the evening.

 

 

 

Stay on the line Cliff, I'm going to go and start mine within the hour, I may need you LOL

 

Have a great day, Lew you can't go wrong with Cliff.

[Big Cliff]

Stay on the line Cliff, I'm going to go and start mine within the hour, I may need you LOL

 

Have a great day, Lew you can't go wrong with Cliff.

 

Sorry my friend, just waiting for Pikeslayer and Pikerslayer Jr. to get here and we are going to go get some walleye. Wiskeywizzard and son just headed out.

 

But I will keep an eye on the board and you have my cell phone if you need it.

 

We are getting Lew all fixed up tomorrow. It will be nice to see him again!

[ketchenany]

Sorry my friend, just waiting for Pikeslayer and Pikerslayer Jr. to get here and we are going to go get some walleye. Wiskeywizzard and son just headed out.

 

But I will keep an eye on the board and you have my cell phone if you need it.

 

We are getting Lew all fixed up tomorrow. It will be nice to see him again!

 

 

Just kidding Cliff, Have great day, too bad the new toys haven't arrived yet! Should be there next week.

 

A

[lew]

Thanks for the generous offer Cliff and I'll see you tomorrow at 3

 

And thanks to everyone else that offered suggestion.

 

I got the carb cleaner but it didn't help but just from my description of the problem over the telephone Cliff has it figured out....I hope :lol:

[Spiel]

Thanks for the generous offer Cliff and I'll see you tomorrow at 3

 

[misfish]

Never fails,,,,,,,,,,,,,,,

 

[lew]

That's OK if your yards only this big Brian >.<

[Beans]

Never fails,,,,,,,,,,,,,,,

 

 

I likes the riding type mower better...

 

 

 

 

 

[skeeter]

Lew, wanna stop by my place on the way to Cliff's and grab my lawnmower?

Just kidding.

I have a problem with mine too, hope fully I can fix it next weekend.

If the shaft from the broken motor will fit the newer one.

 

 

 

 

Tried to fire up the lawnmower and it didn't turn over like it did 2 weeks ago, then it locked up tight on the 4th pull.

Saturday, Had to fix the leak in the stihl gas trimmer, then remove the engine from the lawnmower as I had a spare engine from another lawnmower .

Get the engine on and fire it up.

Fired up on the 3rd pull----yahoo..........

Went to cut the grass and it wasn't cutting it.

Blade is sharp and it is spinning, so I lowered the lawnmower to it's lowest setting and it was just barely taking the top of the grass off.

Measured the old motor from the motor to the blade, 4.5 inches

Measured the new motor the same way, 3.5 inches. :wallbash:

[ckrb2007]

10yrs ago I grabbed a lawnmower off the side of the road with a note the said "FREE...needs a new wheel". I brought it home, put a new set of wheels on it an it's the best mower I've ever had. I use regular gas, never used stabilizer in it, haven't change a plug since finding it, and never added oil. The thing is a beast and it starts every time on the 3rd pull. lol It's now my "up north trailer mower" and I used it this weekend after sitting in my shed over the winter since november.......3 pulls and away she went.