OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Engine Will Run but Hunts/Misses - Suggestions

Hi All

Thanks for the welcome,
Well here comes the first question, The wife has dobbed me in to look at one of her friends mowers B&S engine with the followings numbers,
Mod 10T502
Type 0416 H1
Code 1110052
Dom 10/2011

Now she has already taken it to a mower shop, they said that the governor spring had gone down the intake (not likely) It runs just (hunting/missing a lot with puffs of black smoke).
What I have done,
1, replaced the carby diaphragm and gasket, cleaned the tank and carby while it was off checked for square/flat mounting surface (got caught once)
2, replaced the governor spring (they lost it)
3, cleaned the air filter and re oiled it
4, replaced the spark plug.
5, checked the key way (just in case) all good

The engine will run but hunts/misses and will not make full power even when you push the governor to max it puffs of black smoke (like it's too rich) been through the forum for about 2 hours last night tried a few things this morning with no luck at this point I am looking a replacing the carby last option as she dose not want to spend a lot (e.g. up to $100.00) so far gasket kit and spring $26.90.

do any of the members have an idea on this issue I am just chasing my tail at the moment.

Thanks in advance YT63

Hi mate,

Sounds like there is still a blockage in the carby. This is a B&S Sprint or classic engine right?

When you cleaned it did you use carby cleaner and blow it out with compressed air?

Here is a pretty good video on how to clean one (Just don't use the wire brush)



Thanks,
Pete

When you are 100% carby is not culprit,zap off the head and have a look at the valves.

Hi Pete,
Thanks for the quick reply, I had a look at the video pretty much what I did less the wire brush,

Unsure if a Sprint or Classic, (cover has 500 series rapid start 158 cc)

Yes carby clean and low pressure air (didn't want to blow out and balls/end seals)

I just went out and run it again to confirm running rich, with the air pressure turned down to .5-1 psi and held the blow gun about 200 mm above the open carby it ran fine after a second or two = low air flow rich mix one would think?

going to try and find a break down of the carby ports ( I think there was a post/link here I seen last night)

Again thanks for your input and Ideas.

Regards,

Derek YT63

Are you really sure these Mod 10T502 Type 0416 H1 as I can't an IPL that this type number with in the 10T502 model.

Now if it has the 795477 carburetor. Some these has a metal jet installed in the nozzle that comes loose and gets lost which would produce an extremely rich condition. Don't have a picture of this metal jet version. Also that nozzle is can be removed and there is a small o-ring under it. This is not available separately so a whole carburetor is the only to fix this if this is the problem.

Hello AVB

10T604 0416 H 1

The IPL for the 10T502's is a common one for Types 0001-3840 anyway.

Here 'tis: http://bsintek.basco.com/BriggsDocumentDisplay/18ktuKXTnfBhU7y.pdf

Looks like they all use that 795477 carby AVB shows above. Unlike his side of the pond, genuine OEM carbies aren't cheap in Oz. There is one FleaBay Oz seller offering a clone for $29, though.

Cheers Gadge,

That is the carby, still got me puzzled as to why it's running rich, I could not find any blockages (dirt etc) how can something so simple be so frustrating

Regards

Derek YT63

Hi Derek, and a warm welcome to the forum. Going by the numbers i believe you have the carby with the pressed in brass jet which sits under the screen filter. They hava a tendency to fall out and hence run rich. When you pulled the mesh filter off it probably fell out and it's now gone to the abyss.
Read this thread, there are some pics of what i'm talking about.
[color:#FF0000][b]CLICK HERE[/b][/color]

If you used automotive carburettor cleaner, more than likely it has damaged some components. That stuff is very unfriendly to any type of plastic, particularly the nylon type polymers used in Briggs carbies.

I have known of blokes who used it on motorcycle carbies, and destroyed the nylon slide guides. Which meant that they had to find replacement carbies. New replacement carb bodies were very very exy...

That second combo of model/type number you give still doesn't fit in with the Briggs numbering system.
THIS webpage has a fairly complete list of the possible combos for the 10T model series; see if you can find something close there.

Check the intake manifold tube, they will often crack on the Sprint engines. Another thing it could be that is unlikely but I have seen it rarely is make sure the crank is straight and blades are balanced.

Hi bigted,

I will have a look in the morning, When the lady got the mower back from the shop and dropped it around the carby gasket and diaphragm were missing so it most likely has dropped out at the shop, guess she will be up for a new carby any idea on $$$.

Regards,

Derek YT63

Still no joy on finding IPL for it at Briggs PowerPortal Site. I found a German copy of the IPL though. Lucky for me as most of it is in English.

Briggs 10T604-609 Type 0111 through 3705 IPL

The carburetor is PN 790206 which appears to be superseded to 795475.

Hi AVB,

Thanks for the link another member Gadge found one in English http://bsintek.basco.com/BriggsDocumentDisplay/18ktuKXTnfBhU7y.pdf

And yes it looks like the carby will be 795475 going to check with Terrace Mowers on Monday for a price and availability I will let everyone know how it goes.

to thanks for your input and help.

Regards,

Derek YT63

That manual I've linked there is for the 10T502 series; I found it before you posted the revised numbers.

A useful B&S site for searching these manuals is http://bsintek.basco.com/MDEXResultsPages/default.aspx
It allows searching by model number only, which can be handy in cases like this.

But it can't find a 10T604 model...

Anyway, this is the English IPL it finds for the 10T602, which covers all of the 10T600 series:
http://bsintek.basco.com/MDEXResultsPages/PDFDisplayPage.aspx?fileName=18ktxIXUnfBhU7y

Sure enough, they all use the 795475 carby. The 10T502's use the 795477.

The ODK Shop has genuine replacements for under $30 HERE

That's the way I'd go. It sounds very like the shop monkeys have lost the jet, as well as the governor spring.

I would make a point of telling the owner why you had to get a complete replacement carby, too!

Tnx Gadge. I discovered that I can search for the model series using the first 4 Alphanumeric characters on the PowerPortal site that will help me in the future searches too. So we all are learning something from this thread. I must be still a live as I learned something new too.
Couldn't put it much better, I run this a lot here too where someone didn't know what they were doing ends up doing more damage than good.


YT63, Good luck with your repairs as now that you the needed part manuals. I wish I could have imaged that jet I was writing about but the sites that had an image had copyright protection on their images. This is the second case of version that had a metal inserted jet. Now the replacement carburetor may not have such a version as Briggs may have switch back over to all plastic jet/nozzle.

Cheers Gadge

I have just placed an order for the carby.

To all thanks for your time and help with this problem hope I can help you all some day in some way.

Regards,

YT63

Hi Gadge and all,

The carby turned up on Monday thanks Gadge,

Update on the mower all sorted now runs like a dream so back to the owner this afternoon, Thanks to all for the help and input/info with the mower issues, I guess she will be bringing her lawn equipment to me from now on total cost $65 ish a lot better than the $300 quoted by the mower shop (could pick up a cheap one on eBay for $150 ish) Again thanks for all the help this thread can now be closed please.

Regards,

YT63

As the topic problem/s have been resolved, I shall now close and lock this thread.