Moose-LandTran
Well-known member
A plastic carb.. I never knew such a thing existed.
How did this guy sell me a dead lawnmower?
- Thread starter Bolster
- Start date
DHS
Well-known member
On the bottom of the carb those little flaps of rubber seem to be messed up. I would get a new carb kit and replace that gasket. Also as far as the engine rpm hunting, that will be fix once you get the carb fixed.
jeepnut24
Well-known member
X2 on all of these points... Start with the fuel cleaner... Don't know how many free mowers my dad has received that wouldn't/didn't/never ran that a simple tune up fixed. At least 10 over the years...
Good luck.
PassnThru
Well-known member
Not plastic - high strength polymer
One has to wonder what carburetor cleaner would do to that. Especially soaking in it.
russlaferrera
Well-known member
It sounds like it's running rich. Adjust the carb.
My 3-doors down neighbor is a self proclaimed small engine repair man. He heard my lawnmower running with the "surging" that you're talking about, walked down and admonished me for the horrible way I took care of my lawnmower. He then "graciously" offered to fix it for free. I got it back two weeks later, mowed the yard once, and never got it started again. I put it out on the curb and guess who came and took it home with him? Oh yeah, same "neighbor". I did some reading up on small engine repair, checked out a whole load of youtube videos on the subject, and I've come to the conclusion that this guy wasn't qualified to repair a torn piece of paper. Oh well, lesson learned. I do all of my own small engine maintenance now.
DHS
Well-known member
On newer carbs they dont adjust, I think epa had something to do with that.
PassnThru
Well-known member
Wouldn't the lack of full power and surging be governor related?
Are you sure you got the governor spring back on correctly?
Are you sure you got the governor spring back on correctly?
TheGrooveking
Well-known member
I think you are on to something. I had a 5 hp mini bike that did the same thing once.
TheGrooveking
Indy_500
Well-known member
I still think you should try cleaning the muffler with an air compressor
dclafleur
Active member
Actually with a month shelf time you very well could have gas gone bad in a months time. Ethanol is hydrophilic and more likely to form condensation. Also the tendency to store gas in plastic containers and half full lawnmowers in hot sheds increases the likelihood of having significant amounts of condensation forming in your tank.
If you can get it in your area use non blended gas if it's going to be stored for any amount of time.
Indy_500
Well-known member
I still doubt the gas could've gotten bad enough to make a little mower not run.
scott37300
Well-known member
I have done a couple of carbs this year and I just buy the rebuild kit right away. They are under 10 bucks for all of them I have needed and are really easy to do. It has all new seals and wear parts. In my opinion the 10 bucks for the rebuild kit is good insurance over just cleaning the carb.
I have self taught all my lawn mower repair over the last couple of years, with some help from the internet. A great site for small engine repair is www.perr.com. From what I have found the repairs are usually fairly simple and not to expensive.
I have self taught all my lawn mower repair over the last couple of years, with some help from the internet. A great site for small engine repair is www.perr.com. From what I have found the repairs are usually fairly simple and not to expensive.
Thanks again guys, now starting easily, reliably on the first pull. I am also using the Davidsfarm technique (finding the Davidsfarm videos was a great tip) of tipping the mower forward for a second or two before starting, to get fuel into the carb. It's running rough, and rich, but not stalling as before. Good work remotely diagnosing my problems, guys. Many thanks.
THE REMAINING PROBLEM is surging and hunting for RPM, with lots of small butterfly adjustments occurring, especially after it warms up a bit. And plenty of carbon on the plug, but doesn't appear to be oil fouling. Looks to be like fine black powder on the plug, but dry.
Fielding a few questions:
1. I'm embarrassed to admit it, but I've been hunting all over for a way to adjust the carb. I agree it's too rich, but I can't find any adjustment screw anywhere in the vicinity. I was able to download a slovakian (!) manual for this engine (it's all B&S has on their website), but see no images or photos related to carb adjustment. Regarding the question about adjusting the choke, there appears to be no choke to adjust.
2. I took the muffler off for testing, as suggested. If it works less well when I put it back on I'll suspect that. And I'll blow it out all the same.
3. Spark plug looks somewhere between newish and new, which makes me suspicious it's been replaced just before the sale. The Slovak manual gave me the gap needed. Appropriately gapped.
4. Full power and governor: I may be wrong, but the spring that is attached to the governor arm seemed awfully slack, the mower never got up to speed, and when I would pull it a bit (as if the spring were tighter) the RPMs would rise and the surging would even out a bit. So I bent a "W" shape in the straight arm of the spring to take up some of the slack, and overall it's doing better and running faster with the modification. I'm staying away from full power (although I can get it by pulling on the governor link) because of the Davidsfarm youtube vids, where he mentions it's possible to over-run the engine (apparently you can pretty easily run these engines at too high an RPM). But regarding your question about them being related: probably, and I don't know if I got it back on correctly, I put it back on as it was when I received it, and according to the photos I took before tearing into it.
5. As I mentioned, I replaced fuel and oil immediately upon getting the mower home. Yes, it did run for a half hour (and mowed a lawn while running) with the new fuel I replaced, when I got the mower home. I simply turned the mower upside down in the opposite direction of the carb and air cleaner (in this case, pivoted over the handle bar) and let the oil and gas run out into my garden. Al Gore would have had a cow if he saw me. No, I have not purchased fuel cleaner yet, I've been using carb cleaner, but I'll get some fuel cleaner and some stabilizer while I'm at it.
6. Metering value thingy...don't know. I sprayed carb cleaner several times into every orifice I could see in the carb, and some into my eyes and nose just for good measure. HEY my sinuses cleared up!
7. The mower was stored in a garage in Riverside, where it got to over 100 degrees one day. So that wasn't good for the gas, I'll get a stabilizer and new gas, and from now on I'll run it dry when I'm done mowing...
8. Scott, ditto, where do you get your kits?
THE REMAINING PROBLEM is surging and hunting for RPM, with lots of small butterfly adjustments occurring, especially after it warms up a bit. And plenty of carbon on the plug, but doesn't appear to be oil fouling. Looks to be like fine black powder on the plug, but dry.
Fielding a few questions:
1. I'm embarrassed to admit it, but I've been hunting all over for a way to adjust the carb. I agree it's too rich, but I can't find any adjustment screw anywhere in the vicinity. I was able to download a slovakian (!) manual for this engine (it's all B&S has on their website), but see no images or photos related to carb adjustment. Regarding the question about adjusting the choke, there appears to be no choke to adjust.
2. I took the muffler off for testing, as suggested. If it works less well when I put it back on I'll suspect that. And I'll blow it out all the same.
3. Spark plug looks somewhere between newish and new, which makes me suspicious it's been replaced just before the sale. The Slovak manual gave me the gap needed. Appropriately gapped.
4. Full power and governor: I may be wrong, but the spring that is attached to the governor arm seemed awfully slack, the mower never got up to speed, and when I would pull it a bit (as if the spring were tighter) the RPMs would rise and the surging would even out a bit. So I bent a "W" shape in the straight arm of the spring to take up some of the slack, and overall it's doing better and running faster with the modification. I'm staying away from full power (although I can get it by pulling on the governor link) because of the Davidsfarm youtube vids, where he mentions it's possible to over-run the engine (apparently you can pretty easily run these engines at too high an RPM). But regarding your question about them being related: probably, and I don't know if I got it back on correctly, I put it back on as it was when I received it, and according to the photos I took before tearing into it.
5. As I mentioned, I replaced fuel and oil immediately upon getting the mower home. Yes, it did run for a half hour (and mowed a lawn while running) with the new fuel I replaced, when I got the mower home. I simply turned the mower upside down in the opposite direction of the carb and air cleaner (in this case, pivoted over the handle bar) and let the oil and gas run out into my garden. Al Gore would have had a cow if he saw me. No, I have not purchased fuel cleaner yet, I've been using carb cleaner, but I'll get some fuel cleaner and some stabilizer while I'm at it.
6. Metering value thingy...don't know. I sprayed carb cleaner several times into every orifice I could see in the carb, and some into my eyes and nose just for good measure. HEY my sinuses cleared up!
7. The mower was stored in a garage in Riverside, where it got to over 100 degrees one day. So that wasn't good for the gas, I'll get a stabilizer and new gas, and from now on I'll run it dry when I'm done mowing...
8. Scott, ditto, where do you get your kits?
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Lookin4'67Galaxieconv
Well-known member
Outta gas...mmm hmmm!
scott37300
Well-known member
I get them from my local kitz and pfiel true value hardware store. They are a briggs and stratton repair center. I also bought one off ebay.
You get them based on a number stamped on the carb, or based on the model/serial number of the mower?
DHS
Well-known member
On your spring there is going to be slack in it. Thats why there is like a slot on the left side of spring. Your best bet is to clean and put carb kit into it, and also straighten the spring back if you bent it. Its is rarely the springs fault for rpm hunting.
DHS
Well-known member
You use the model-type-code off the engine.
DHS
Well-known member
Im not sure on the lawn boy. The model-type-code works on the Briggs. Never messed with the 2 cycle lawn boys, but I think that crank seals leaking will cause it not to run right. Also I think the mufflers are more prone to clogging.
scott37300
Well-known member
The briggs I have done the model plate was just above the muffler, they can also be on the shroud, depending on the mower they might be somewhere else. I did a craftsman and it was easier to just use the sears site and the craftsman model numbers to get the parts list.
Here is a link on how to identify a briggs engine, not sure what engine your lawnboy uses but maybe this will help. http://www.briggsandstratton.com/maint_repair/BS_modeltypecode.pdf
First of all, that carb the OP has has no adjustment so don't waste any more time looking. It's surging up & down because it needs a new diaphragm & gasket. Actually, that is all the carb kit will consist of, and the part # is 495770(probably have 2 or 3 in my parts cabinet). Those kits are probably 8 or 10 bucks. Good thing they are cheap, because they need to be replaced every couple years. Those plastic carbs warp along the back edge, and when they do, they **** the diaphragm in & don't run right. You can replace the carb on most of those for $20-25, but the new carbs warp like the old ones. You will need the model type & code to get the right carb though. these numbers will be stamped in the blower housing above the spark plug or on a tab above the muffler, if it's new enough.
When you took it apart, did you make sure to put the spring back on? if you didn't, it won't run right.
Engines with those plastic carbs are super common on the low end junk found at box stores. You know, the stuff that is around 150-$175 new, no self propel, usually no bagger.
bull, is your lawn boy powered by a tecumseh or a briggs? What's it doing?
For those who are wondering, i was a mechanic at a lawn mower shop for 3+ years.
When you took it apart, did you make sure to put the spring back on? if you didn't, it won't run right.
Engines with those plastic carbs are super common on the low end junk found at box stores. You know, the stuff that is around 150-$175 new, no self propel, usually no bagger.
bull, is your lawn boy powered by a tecumseh or a briggs? What's it doing?
For those who are wondering, i was a mechanic at a lawn mower shop for 3+ years.
I believe it is a Briggs, 6HP or something like that. I will check.
I guess I shouldn't muck up Bolster's thread with my own mower issue, so I will start another or, if you are a man with a plan, we can PM
Bolster, I seriously doubt you can fix that carb. Just replace it, they're usually under $25.
Bull it's your choice, but I will give you fair warning. I won't be around much tomorrow or wednesday, going to be real busy after work the next couple days.
Bull it's your choice, but I will give you fair warning. I won't be around much tomorrow or wednesday, going to be real busy after work the next couple days.
Tool Pants
Well-known member
My lawn mover story.
3 1/2 years ago at my office building, which is in a residential area. There is a large dumpster in the parking lot covered by a fence with a gate. From time to time I would throw stuff from the office into the dumpster. The local residents sure new about it, because there was always household stuff in or next to the dumpster. Everything from a bed to a bookcase to a chair.
One day I saw a Craftsman lawn mower tilted up between the fence and dumpster. Leaking fluids. Thought it had blown the piston. I had my pickup at work that day. Don't know why, but I decided to take it home to see if I could get it to work. If I had any sense I would have taken a stray cat home that day instead.
The last time I took a lawn mower apart was 40 years ago, and they have changed. It has a dead man thing and the cable was broken, so I used a clamp to bypass it. Still would not start. Took all the coverings off to look for the points. No points. Took the carb off and saw junk in the float bowl. Cleaned it. Did not work.
I bought a new cable from Sears. Then a carb rebuild kit and a new plug. It would start, but leaked fuel from the carb. I traced it down to a pin hole in the aluminum float bowl that was not leaking until I soaked the carb. Bought a new float bowl. Changed the oil. I even bought the owners manual from Sears.
Did I forget to mention. This was a California mower. Strict emission stuff in my state. When I tried to look up parts on the net I had to look for the * to make sure it was for a Calif. model.
I even sharpened the blade with a file.
It has the bulb you push 3 times to prime the carb. It starts on the first pull.
Now, for the weird part, I don't have a lawn. I have a house but took the lawn out years ago during one of our droughts. Also, I do not like cutting grass. When I had a lawn it was small so I used an electric mower, which I still have.
To test out the cutting action I went over to my neighbor's house and cut his front lawn. For free. I was only going to try the mower out on a small patch, but ended up doing the entire front lawn.
3 1/2 years ago at my office building, which is in a residential area. There is a large dumpster in the parking lot covered by a fence with a gate. From time to time I would throw stuff from the office into the dumpster. The local residents sure new about it, because there was always household stuff in or next to the dumpster. Everything from a bed to a bookcase to a chair.
One day I saw a Craftsman lawn mower tilted up between the fence and dumpster. Leaking fluids. Thought it had blown the piston. I had my pickup at work that day. Don't know why, but I decided to take it home to see if I could get it to work. If I had any sense I would have taken a stray cat home that day instead.
The last time I took a lawn mower apart was 40 years ago, and they have changed. It has a dead man thing and the cable was broken, so I used a clamp to bypass it. Still would not start. Took all the coverings off to look for the points. No points. Took the carb off and saw junk in the float bowl. Cleaned it. Did not work.
I bought a new cable from Sears. Then a carb rebuild kit and a new plug. It would start, but leaked fuel from the carb. I traced it down to a pin hole in the aluminum float bowl that was not leaking until I soaked the carb. Bought a new float bowl. Changed the oil. I even bought the owners manual from Sears.
Did I forget to mention. This was a California mower. Strict emission stuff in my state. When I tried to look up parts on the net I had to look for the * to make sure it was for a Calif. model.
I even sharpened the blade with a file.
It has the bulb you push 3 times to prime the carb. It starts on the first pull.
Now, for the weird part, I don't have a lawn. I have a house but took the lawn out years ago during one of our droughts. Also, I do not like cutting grass. When I had a lawn it was small so I used an electric mower, which I still have.
To test out the cutting action I went over to my neighbor's house and cut his front lawn. For free. I was only going to try the mower out on a small patch, but ended up doing the entire front lawn.
Attachments
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Need4racin
Banned
x2. search on his page for "mower" "carb" "fuel" "spark" "2 stroke" etc
There's no need to run fuel stabilizer, it takes probably over a year for fuel to get gummy, maybe multiple years. You will know if the spark plug is fouled, it will be PACKED with solid burnt oil, to the point there is absolutely no gap for the spark.
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Burgerkong
Well-known member
OT, but...
Mickey O
Well-known member
Chump.
............
............
Hank McMauser
Well-known member
giving this thread a 5 star for merging my 2 favorite moves (still aint sure how you guy's managed it (oh brother where art thou, and sling blade) Y'all got any o' them french fried pertater's? I like mine with mustard mmmmm hmmmm yep. ......prolly have to order that part from bristol, Nearest briggs & stratton man is in bristol,take two weeeks.
Frank
Well-known member
Here are my experiences:
Modern 3.5hp and lower B&S engines with the integral carb/tank: Seen this problem several times. Not sure if its what you are experiencing. Just one drop or two of water will give it hell. Even when you have drained the tank and think it is bone dry and put fresh gas, there is a place where the water hides. If you pull the tank and the carb, look in the hole where the short screened pickup was (not the long one going into the fuel.) Its a shallow hole with a crisscross pattern in the casting at the bottom. There you will find water/trash/both. Clean it out. Gently pull off the screened cup and make sure there isn't any water trapped there. I have fixed several B&S lawnmowers this way. You cannot leave one of these out in the rain like we used to do.
Crapsman: Had a 6hp self propelled electric start model. It was always hard to start. At one point, the coil had come loose and was dragging on the flywheel. Water in the bowl was common, but not too hard to clean out. The needle seat is made of neoprene or some garbage and deteriates over age and will plug up. It seemed I was always having to work on the thing. I finally took it and left it beside some dumpster with the fluids draining out along with a mongrel cat that I hated.
Modern 3.5hp and lower B&S engines with the integral carb/tank: Seen this problem several times. Not sure if its what you are experiencing. Just one drop or two of water will give it hell. Even when you have drained the tank and think it is bone dry and put fresh gas, there is a place where the water hides. If you pull the tank and the carb, look in the hole where the short screened pickup was (not the long one going into the fuel.) Its a shallow hole with a crisscross pattern in the casting at the bottom. There you will find water/trash/both. Clean it out. Gently pull off the screened cup and make sure there isn't any water trapped there. I have fixed several B&S lawnmowers this way. You cannot leave one of these out in the rain like we used to do.
Crapsman: Had a 6hp self propelled electric start model. It was always hard to start. At one point, the coil had come loose and was dragging on the flywheel. Water in the bowl was common, but not too hard to clean out. The needle seat is made of neoprene or some garbage and deteriates over age and will plug up. It seemed I was always having to work on the thing. I finally took it and left it beside some dumpster with the fluids draining out along with a mongrel cat that I hated.
cowboy73
Well-known member
You might also try taking the head off and cleaning the carbon off the top of the piston and the from around the valves. I ave seen them gunked up enough to not make them run right.
Indy_500
Well-known member
x2!!!!!...
Sweet, sweet success. Thanks to you, GJ-ers! I truly appreciate all the excellent advice given in this thread.
For those searching and finding this thread in the future, not sure I can remember everything I did, but here were some of the major elements of the fix, most of them at the suggestion of the folks who contributed to this thread:
1) Dumped original oil and gas. Refilled with 30-wt oil. (Next oil change will be to 30-wt synthetic.)
2) Rinsed out air filter and re-oiled it.
3) Met a guy here at GJ who gave me the B&S repair manual (Thank you, friend! You know who you are!)
4) Removed tank & carburetor and cleaned it thoroughly with carb cleaner, then blew it dry with air. (Did this twice.) Cleaned depressed area in gas tank as indicated in posts above, where water collects. Put a straight edge across the bottom of the carb and could not find a warp, so decided to keep this carb rather than replace.
5) Blew out the muffler...seemed to be clear.
6) Gapped the plug to .030. Would have cleaned it but it appeared to be relatively new and in good shape.
7) Got the filter/diaphragm kit at local lawnmower repair shop, as advised above (cost $5) and installed it as per instructions in B&S repair manual, right down to the order of screw tightening and inch-lbs specified in the manual. (This DID stop the surging and RPM hunting, as predicted above!)
8) Refilled with fresh gas, added both stabilizer and "silver" bottle STP, the one that bills itself as "restoring fuel systems." (These additives were scaled to the amount of gas I used; they were added according to the proportions listed on the products, not just dumped in randomly.)
9) To start, bulb prime as indicated, but also tip the mower forward at about 40 degrees, for about 2 seconds, which fills portions of the carb for easy starts.
10) Undid my wrongheaded "fix" of making the the throttle spring shorter by bending it. Once the spring was straightened, I bent the sheet metal it affixes to instead (as per manual) to attain appropriate RPMs...fast, but not very fast.
11) Started 'er up (one pull, consistently!), and gave the lawn a test mow. Then put 'er in front of the garage, to take a portrait of my $45 lawn queen for y'all.
I owe all of you a beer.
For those searching and finding this thread in the future, not sure I can remember everything I did, but here were some of the major elements of the fix, most of them at the suggestion of the folks who contributed to this thread:
1) Dumped original oil and gas. Refilled with 30-wt oil. (Next oil change will be to 30-wt synthetic.)
2) Rinsed out air filter and re-oiled it.
3) Met a guy here at GJ who gave me the B&S repair manual (Thank you, friend! You know who you are!)
4) Removed tank & carburetor and cleaned it thoroughly with carb cleaner, then blew it dry with air. (Did this twice.) Cleaned depressed area in gas tank as indicated in posts above, where water collects. Put a straight edge across the bottom of the carb and could not find a warp, so decided to keep this carb rather than replace.
5) Blew out the muffler...seemed to be clear.
6) Gapped the plug to .030. Would have cleaned it but it appeared to be relatively new and in good shape.
7) Got the filter/diaphragm kit at local lawnmower repair shop, as advised above (cost $5) and installed it as per instructions in B&S repair manual, right down to the order of screw tightening and inch-lbs specified in the manual. (This DID stop the surging and RPM hunting, as predicted above!)
8) Refilled with fresh gas, added both stabilizer and "silver" bottle STP, the one that bills itself as "restoring fuel systems." (These additives were scaled to the amount of gas I used; they were added according to the proportions listed on the products, not just dumped in randomly.)
9) To start, bulb prime as indicated, but also tip the mower forward at about 40 degrees, for about 2 seconds, which fills portions of the carb for easy starts.
10) Undid my wrongheaded "fix" of making the the throttle spring shorter by bending it. Once the spring was straightened, I bent the sheet metal it affixes to instead (as per manual) to attain appropriate RPMs...fast, but not very fast.
11) Started 'er up (one pull, consistently!), and gave the lawn a test mow. Then put 'er in front of the garage, to take a portrait of my $45 lawn queen for y'all.
I owe all of you a beer.
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