Export thread

now power high end / black smoke

#1

M

mr.farmall

Hello
I have a mower with a B&S 21.5 v twin 407777 0128 e1.
About a month ago it started to load up the engine, almost as if it were chocked, while cutting tall grass, spewing black smoke. I throttled it back and it when back to normal. finished cutting without further troubles. Since then it has loaded up at high throttle even without the blades being engaged. A couple weeks ago with only medium throttle every time it hits a somewhat heavier cutting load, the engine loads up again, but will always clear up when throttled back. But now it is to the point that I can only throttle it half way before it starts loosing power and spewing black smoke regardless of the blades engaged or not.
I have pulled the carburetor. the throttle and choke work easily and well. It's been cleaned with an ultrasonic jewelry cleaner in a mixture of "simple green" and water. It looks really nice,( didn't look so bad to begin with). blew out the passages with low pressure air. all looks well. The float works good, doesn't have any gas in the float and the rubber shut off seal looks great. The only thing I was able to see was the tiniest bit of debris in the bottom of the bowl next to the electric shut off valve.
I will put it back together tomorrow.
Spark plug was a little fouled with a little black soot on the electrode, but not much. I've cleaned it up and have a spare. Air cleaner is in good shape, almost new.
I hope cleaning the carburetor will help the situation, but many of you would have a better knowledge of what is happening.
Any suggestion would be helpful.
Thanks Rex


#2

J

John Fitzgerald

Have you checked for gasoline in the oil, which would be raising the oil level, and thinning the oil? If your float bowl overfills, gasoline will run into the crankcase. A band aid fix is to install a fuel shut off valve in the line and shut it off every time you stop the engine. Better to fix the problem of the overflow, IF that is the problem, and also install a shut off.

I have seen this exact thing happen two or three times, and every time, it is gasoline in the crankcase causing it.


#3

M

mr.farmall

John Fitzgerald said:
Have you checked for gasoline in the oil, which would be raising the oil level, and thinning the oil? If your float bowl overfills, gasoline will run into the crankcase. A band aid fix is to install a fuel shut off valve in the line and shut it off every time you stop the engine. Better to fix the problem of the overflow, IF that is the problem, and also install a shut off.

I have seen this exact thing happen two or three times, and every time, it is gasoline in the crankcase causing it.
Click to expand...

Thanks for the tip. I took this info and just pulled the dip stick, oil looks good, not thin, doesn't smell like gas and is a little on the low side. when this is resolved, I think it needs an oil change.


#4

Boudreaux In Eunice La.

Boudreaux In Eunice La.

Mr, Farmall do you have the 2 jets in your carb or just 1 ????? You are running rich, too rich...........


#5

M

mr.farmall

Boudreaux In Eunice La. said:
Mr, Farmall do you have the 2 jets in your carb or just 1 ????? You are running rich, too rich...........
Click to expand...

it looks to me like two jets. First picture it the bottom turned upside down. Second picture it the input of the carb toward the air intake. I don't see any way that it can be adjusted.

Attachments







#6

Boudreaux In Eunice La.

Boudreaux In Eunice La.

That doesn't look like a Nikki carb ???? It must be an older carb than what I am thinking of..... I have the kits for the Nikki in stock and the gaskets sure don't look like those.......

Here is a link to a video.......You can skip the comedy skit in the beginning if you want but Taryl is a funny guy...........Is this your carb ???

https://youtu.be/emsafzhGLC0

Let me know Mon Ami ~!~!


#7

M

mr.farmall

Boudreaux In Eunice La. said:
That doesn't look like a Nikki carb ???? .Is this your carb ???
Click to expand...

looks very much the same, in fact it looks identical, but mine has a plastic tower type 4 hole tube over the jets. couldn't really tell if the one in the video had it or not, but I'll check better tomorrow. mine does have nikki molded into it, but I dont remember a gasket of any type like he pulled out. will check better tomorrow.


#8

Boudreaux In Eunice La.

Boudreaux In Eunice La.

Well I looked your engine up and sure enough it shows that gasket kit I have in stock , but that gasket around the emulsion tubes is different than my gasket Mine is made like a double figure 8 side by side...... There are two different gaskets for certain year models..

I thought something looked different........ Oops I made a mistake...........

What is your code number ?? that would be the numbers after the model and type #'s


#9

I

ILENGINE

Acts like a high speed jet issue. O ring around the jet cracked allowing fuel to be pulled around the jet.


#10

Boobala

Boobala

Here's a lil info on the Nikki 2 Bbl. carb .........

https://www.lawnmowerforum.com/showthread.php/50891-2-Barrel-NIKKI-CARB-INFO


#11

M

mr.farmall

Boobala said:
Here's a lil info on the Nikki 2 Bbl. carb .........

https://www.lawnmowerforum.com/showthread.php/50891-2-Barrel-NIKKI-CARB-INFO
Click to expand...

Great info from this link. not just a little but a lot! couldn't sleep much early this morning so I went through them all!
I have the oldest model, the one with the black, not white parts and the steel bowl.
I'm anxious to get started again this morning.


#12

M

mr.farmall

Boudreaux In Eunice La. said:
That doesn't look like a Nikki carb ???? It must be an older carb than what I am thinking of..... I have the kits for the Nikki in stock and the gaskets sure don't look like those.......

Here is a link to a video.......You can skip the comedy skit in the beginning if you want but Taryl is a funny guy...........Is this your carb ???

https://youtu.be/emsafzhGLC0

Let me know Mon Ami ~!~!
Click to expand...

"Taryl Fixes All" hit it right on the head. funny video, but more importantly, he isolated the problem to just what I have. that gasket has two of the holes almost plugged. the utrasonic cleaner cleaned every port and passage, but it didn't touch this plugged gasket. I'm excited to get it corrected and try it out latter today.
I have the oldest model with the jets in the aluminum not in the plastic tubes.


#13

M

mr.farmall

Boudreaux In Eunice La. said:
What is your code number ?? that would be the numbers after the model and type #'s
Click to expand...

the code # is 001016YG.
here are some additional photos. the nikki carb, the black emulation tube, the plugged gasket before and after cleaning. two hole were almost plugged and a third one was partially plugged.
it's going to start raining and I need this mower today, so I will put it back together and see if it works. If not, I'll be looking for new parts.

Attachments













#14

M

mr.farmall

Re: no power high end / black smoke

Success! runs great now.
Thanks so much to everyone for your comments and knowledge.
the plugged holes in the gasket were from the rubber deforming and not from debris. I think this needs replacing. but for now, I have to use it today!!
Now another problem, while putting it back together, cracked the gas tank! Bummer! I didn't think it got hit very hard, maybe it's getting brittle!


#15

Boudreaux In Eunice La.

Boudreaux In Eunice La.

mr.farmall said:
looks very much the same, in fact it looks identical, but mine has a plastic tower type 4 hole tube over the jets. couldn't really tell if the one in the video had it or not, but I'll check better tomorrow. mine does have nikki molded into it, but I dont remember a gasket of any type like he pulled out. will check better tomorrow.
Click to expand...

Yes you have the older model carb.. I am so used of the newer ones coming in all the time.... Your engine is almost 20 years old..........

Glad we could help you fix your issue.... Remember don't $***** a brick when you go to buy a new kit for that carb .....

Those kits run 75 bux.......... You might could get away with just that gasket .................


#16

M

mr.farmall

Boudreaux In Eunice La. said:
Your engine is almost 20 years old..........

Glad we could help you fix your issue.... Remember when you go to buy a new kit for that carb,
Those kits run 75 bux.......... You might could get away with just that gasket .................
Click to expand...

Thanks again so much. I'm not familiar with your posts, are you a repair shop, do you have a web site? Next in line is an oil change and filter, tank it up with fuel, and get the yard looking good again for my sweet wife.

I'm thinking I need to tear it apart latter and replace this gasket and at least the one on the bowl also.


#17

Boudreaux In Eunice La.

Boudreaux In Eunice La.

mr.farmall said:
Thanks again so much. I'm not familiar with your posts, are you a repair shop, do you have a web site? Next in line is an oil change and filter, tank it up with fuel, and get the yard looking good again for my sweet wife.

I'm thinking I need to tear it apart latter and replace this gasket and at least the one on the bowl also.
Click to expand...

Yes I own a shop and I am a Brigg's dealer.....


#18

Boobala

Boobala

BE SURE you use LOC-TITE on the screws holding the butterfly plates to the shafts... ( BLUE,.. NOT the RED ) don't want to "feed" those screws to those "innards" of the eng. had good advice ...... SHOP prices and CONTENTS of kits, be aware of the "schitt-kits" out there, especially from Evil-Bay ........ also if ya can't find a used ( or new ) tank we have videos of repairing them... :thumbsup:


#19

M

mr.farmall

Boobala said:
also if ya can't find a used ( or new ) tank we have videos of repairing them... :thumbsup:
Click to expand...
I looked at lots of peoples attempt to repair plastic gas tanks. read comments and instructions. But wasn't satisfied with any of them. most of them used epoxy or an epoxy product like the past mix products. But testimonies a few weeks latter showed that they just didn't seal well and continued to leak down the road a ways.
I could not find the videos you mentioned here on the site. I guess I just don't quite know how to navigate this blog well, but I did get it fixed.
It is made out of polyethylene. Just so happens that milk jugs are also made of polyethylene. I cut one up into strips to use as a welding rod filler, then used a soldering iron (a very large iron 1/2 inch wide) to melt the rods and tank together. getting it just the right temperature was really tricky. Too hot and it turned clear and ran or dropped, not hot enough and it wouldn't join completely. It was surprising how much filler I had to use, probably most of a one gallon jug cut up!
After an hour of trial and error, I finally got the hang of it and it turned out really well. even looks decent! But I think that if it cracked so bad in one spot, it's going to crack in another.
When it cracked, the two parts separated and warped really fast, in my case, in just a couple of hours. this left the cracked edges not aligning nor touching well.
I know that milk jugs I use in the green house also get hard and brittle and after a couple of years or so, end up breaking easily when bumped. I suspect that old polyethylene gas tanks do the same. Mine was a clear/white tank, not a black tank, it had turned to a yellow.
thanks again for your knowledge that made it work!


#20

Boobala

Boobala

mr.farmall said:
I looked at lots of peoples attempt to repair plastic gas tanks. read comments and instructions. But wasn't satisfied with any of them. most of them used epoxy or an epoxy product like the past mix products. But testimonies a few weeks latter showed that they just didn't seal well and continued to leak down the road a ways.
I could not find the videos you mentioned here on the site. I guess I just don't quite know how to navigate this blog well, but I did get it fixed.
It is made out of polyethylene. Just so happens that milk jugs are also made of polyethylene. I cut one up into strips to use as a welding rod filler, then used a soldering iron (a very large iron 1/2 inch wide) to melt the rods and tank together. getting it just the right temperature was really tricky. Too hot and it turned clear and ran or dropped, not hot enough and it wouldn't join completely. It was surprising how much filler I had to use, probably most of a one gallon jug cut up!
After an hour of trial and error, I finally got the hang of it and it turned out really well. even looks decent! But I think that if it cracked so bad in one spot, it's going to crack in another.
When it cracked, the two parts separated and warped really fast, in my case, in just a couple of hours. this left the cracked edges not aligning nor touching well.
I know that milk jugs I use in the green house also get hard and brittle and after a couple of years or so, end up breaking easily when bumped. I suspect that old polyethylene gas tanks do the same. Mine was a clear/white tank, not a black tank, it had turned to a yellow.
thanks again for your knowledge that made it work!
Click to expand...

Check this out, I have further info if needed ...... Boo

https://www.lawnmowerforum.com/showthread.php/47559-P


Footer Links 1

Top