The coils go bad often enough on these. In fact, you can have spark but the cd in the coil will fire it intermittantly or just plain at the wrong times. A business card between the flywheel and coil is an easy gap tool. If you pulled the flywheel, I would urge you to double check the flywheel key first. BTW, the fuel pump is on the front of the carb. If you do decide to set it ablaze and run it down the hill, post the you Tube link. Remember, to never beat it with a stick when it is a blaze.

It seems to me that you may be getting too much fuel at this time. That can be totally unrelated to your previous problems.
If there is a piece of crud lodged between the carb needle/seat, fuel may be simply overwhelming the engine. A puncture float can do the same thing.
When it does run, are you getting excessive black smoke? That's a sign of too much fuel.

Hello guys, thanks for the quick response.

Tomplum: If these ig. coils do commonly play up and fire at random/intermittant times as you suggest, then that sounds very much like what is doing to me. (What is the cd??). I am going out soon and I am going to re-gap the coil with the business card, good idea!! (That is a tool I have many of).

I know the flywheel key is ok, because I dropped it in the grass and my wife and I took ages to find it. After that it did kind of had my undivided attention. (Stupid thing is made out of some form of Alum. so a magnet won't find it in the grass ... Real Handy B&S thanks - ha!) But it and the keyway were fine. I was hoping it wasn't because it would have made sense and been an easy fix.

I will let you know soon if the re-gap adjustment makes any difference.

I like the You Tube suggestion - my mind was just wondering if there is some way to raise money from a video clip like that, "Like maybe enough cash to buy a new Lawn Tractor - ha ha."

Bill: Could it just be because the choke is on full whilst trying to start it? I did wonder if it was flooding it though and I had a carb. problem. Problem is unless I use full choke it has never started (from cold) before.

If I do any work on the carb. will I need any gaskets/seals etc??

IF not I will check the needle and seat first then the float as suggested, can you give me a quick guide to locating the needle. I haven't explored the carb. before. Is it the large screw toward the base of the carb. on the right hand side?? (when facing the engine).

Yes there is fair bit of black smoke on starting and then it seems to clear.

I will wait for your reply before looking at the needle.

I am back again.

Tomplum: I reset the coil with the business card, it was about where it was already and as a result ufortunately has made no difference.

As a result of all the starter motor winding I have been doing, now the battery is on the charger. I wondered when it was going to go flat.

If I do need to replace the coil, I wondered if anyone can tell me the correct part no. for it to make sure I get the correct one.

I think it is B and S # 394891 but the ones I have found online only say it is for up to model 422700. Mine is model 422707, will this be the right one?

394891 is the correct part#
Go to the Briggs website (at the link) and down load the IPL for your engine. It should help "some"

Here is a link that might be useful: B&S

Hi Bill,

Thanks for the part no and the link. Nothing worse than ordering the wrong part.

Could you please offer me some assistance with the question to you in my first reply regarding the carb. please. Re gaskets and needle location.

I really do appreciate the help mate.

Kev.

The needle is #105 on page 6. (carb 125A)
I'd get the overhaul kit and just do the carb properly if it was me, but for what you need to do, you could probably get by without new gaskets.
With the complete kit, you get the parts to also rebuild the fuel pump too. This would eliminate a couple potential problem areas at the same time.

Bill has a point about too much fuel- especially if you note it puddles when sitting. I was concerned about the key as this is a heavy enough flywheel and if they do not get fully secured, they will shear the key. This creates a timing issue. When I do these carbs, I clean them right on the machine. Spray it down on the outside and split it w/ the 4 screws. The pump is a little tricky this way. Watch carefully for the small springs!

Bill: Mate thanks for the B&S link that is a great help and I see the needle you are referring to now.

I agree with you about doing it properly and buying the kit for the carb. At least if I do the kit it rules out that as a problem and it is probably overdue for a good going over.

I will have to wait until tomorrow to get a carb. kit and coil. Should I buy the both the coil and kit before doing the carb? (Probably not hey, I might hold off on the coil?)

How do I know how far to wind the new needle in to tune it correctly? I will count the turns when I pull the old one out and wind the new one in the same no. but what if the old one was in the wrong place?? Can you guide me on this please??

Tomplum: I like the idea of doing it on the machine and thanks for the tip on the springs (Especially after losing the Flywheel Key in the grass - I would never hear the end of it from my wife). I imagine they will be obvious where they come from when reassembling it? I can see what looks like a spring or two on the pump on the B&S site Bill gave me the link to.

Can you also suggest any good online stores to order these parts from, that will deliver to Brisbane Australia. The parts appear to be cheaper on line than prices I have got here, but so far nothing is said about delivery to Aus. I'm sure someone offers delivery door to door via UPS or something such to us spanner spinners down here.

I'd just get the carb kit and maybe a set of spark plugs? for now. (plugs offer the "best bang for the buck" IMO when one just wants to "throw parts" at an engine. They can often cover a multitude of other ills for a rather reasonable price.

I'm not sure how much S&H would cost you for an "international" order??? Probably a lot?

Coincidently, my niece is flying into Brisbane in a few weeks on her way to Papua NG. No, I won't even ask her:-)

You might check the link for a dealer

Here is a link that might be useful: Link

Bill: Thanks I think I agree - kit & plugs.

Yes I am sure it would bump the price a fair bit, I will ring around tomorrow (Thanks for the local link - you are like the Google of B&S, what a wealth of info). I had got 2 prices here already and both were much more expensive than those I have found online, that was the only reason I was considering it.

I think your niece would thank you for not asking her and I wouldn't want to put anyone out. Nice of you to consider it though, thanks.

I will ring around and get a kit and fit it and be back to let you know how it is going. I am not sure how soon I will be able to fit it though due to working long hours. (Maybe a few days to a week).

I will be sure to tell you both what finally does the job also, nothing worse than reading through other peoples forums and you get to the bottom and they don't tell you what solved the problem....I hate that!!!!

Hi guys,

I have an update on the ig. coil I thought I would let you know about.

Today I had the opportunity to take the coil to one of the B&S Dealers, (that Bill gave me a link to - Thanks again Bill), and they were able to test the coil for me while I waited. The test only took a few minutes and what's more they didn't charge me anything - nice.

The verdict - "Cactus Jack, Ka-put, R.I.P., Kangaroo Edward (or Roo-Ted for non Australians)". Yes that's right it's stuffed.

Now that I know for sure, I plan to get one in a few days and will hopefully have it fitted within a week or so.

In the meantime I plan to do the carby as discussed.

I will keep you posted about the outcome, but I feel confident it is going to be a good result. (If it isn't, look on You Tube for a FireBall on Wheels - ha ha).

Stay Tuned, I'll be back.

G'Day Guys,

I told you I'd be back to let you know the outcome.

I have good news and bad news.

The good news is,
I replaced coil without touching the carb. and it runs again . . . Yah Hoo!!

I thought I would go this way first as a process of elimination and prove that it was the coil and it obviously was.

I did also get the carb. kit and I do intend to fit this as Bill suggested and I believe that it will only improve the running of the engine. I also bought a new air filter and pre filter for it to breath easier and I will fit these after doing the carb. kit.

I bought the parts online from America and imported them cheaper than I could buy them here locally in Australia . . . Stupid hey! This is why I have been a little while getting back.

The Coil is an aftermarket item but looks identical right down to the "THIS SIDE UP" cast into the top of the plastic to ensure it is fitted the correct way with the leads coming out on the opposite side of the coil to the spark plugs (That would be a trap for some people).

I am very happy with the result and would like to thank both Bill and Tom for all of your help. This GardenWeb forum is a great service.

(Oh by the way) The Bad news is,
You won't see it as a fire ball on You-Tube . . . Sorry Guys!!

Thank you.

Glad it's working.
I imagine the reason the parts were so cheap is that our $ is in the toilet!

Hi Bill,

Yes mate that could be the case - I paid AU$1 for about US$0.91. I also wondered if it is also the fact that your country is so massive and therefore quantity of parts available and competition for business might affect the price. We are only a drop in the bucket (in Aus) when it would come to spare parts I imagine.

In any case I can appreciate your concerns about your $.

Well mate, keep you chin up and thanks again for your help.

Ps. I hope your neice enjoyed PNG.

A tip: When reassembling a carburetor that has little springs to keep in place, or other infernal teeny parts that fall out, secure them with a dab of heavy wheel bearing grease, which will keep them in place until you get it reassembled, then the gasoline coming in will melt the grease--and everything will be ok.

"Ps. I hope your neice enjoyed PNG."

She made it back, uneaten!:)
I'm still waiting for her "Journal".
She lived in OZ for about 3-4 years in the late 90's. She had residency status and even a govt. job, working on noise abatement issues around the Sydney airport. She was a govt. "liaison" with the homeowners that were getting soundproofing for their homes. I guess the locals loved her accent! Similar to the way we fall for the Aussie accent.

Hi Rusty,
Thanks for the tip. That is a rather clever trick and I will try it thanks. Anything to make a job easier is a gooooood thing.

Hi Bill,
Mate thanks for the laugh -"She made it back, uneaten!:)" that is funny. She sounds like she knows her stuff, (if she was working with the govt), it must run in the family hey. Yes we Aussies are a sucker for an accent also.

Thanks to you all for your help. If I need any help in future I know where I will be heading to ask questions.

Over and Out . . . . . . ("click").

I have a very similar problem with a Briggs & Stratton 17 HP engine. I have put in a new carb overhaul kit. (The float was gunked up pretty bad, but now looks new, checked for leak or holes in it, found no indication that float is damaged.) Put carb back on engine. Engine runs, but poorly. It sounds likes it chugging, noticing black smoke out of exhaust especially at Idle.

One thing I didn't notice in all the above posts. Is the adjustment needle on the carb an IDLE adjustment needle or a main needle? What is the initial setting?

The engine does have spark. Although one spark plug shows more of an orange spark rather than blue. Both plugs were damp from unburned fuel when I removed them. (They are old plugs.)

Engine running: It'll sit and run. I can drive the tractor. However when I slowly engage the mower blades (blades are new, bearings are good, belt is new) the engine dies, unless I quickly disengage the blades and apply full choke.

Heading out to store to get new spark plugs this morning. I've already poured quite a bit of money in this beast. I may be the one who has a rolling ball of fire!

"I have a very similar problem with a Briggs & Stratton 17 HP engine."

Engine model number?

Walt Conner

Model:42A707 Type: 1653-01 Code starts with 96 (year)

I put in new spark plugs last night, but no change in engine symptoms. Runs ok until I engage deck blades, then dies UNTIL I add choke and then it recovers. But have to run it nearly full choked. Makes no sense, normally an engine under load neads a leaner mixture, not richer.

Is that needle on the carb only an idle adjustment needle? I looked at a diagram on the briggs and stratton.com site for this engine, but the needle doesn't look quite the same. No needle lock was on this, like it shows in the briggs diagram.

By the way. I got this beast a few months ago used and in several pieces. There is no model number at all on the tractor itself.

Thundar already solved his engine problem (leak in vacuum line to fuel pump)

Here is a link that might be useful: other post

Correction. Problem not solved. Engine ran good for one run. Then back to chugging and not running under load without choke.