Briggs 422707 Firing one cylinder

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  #1  
Old 05-28-09, 06:48 PM
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Briggs 422707 Firing one cylinder

Hello,
I have a Briggs 422707 18Hp IC Twin in a Craftsman c459-60418 lawn tractor.

This mower hasnt ran in several years. but its been stored inside during that time. First thing i did when trying to get it going was a thorough carb cleaning, including carb dip and i ran soft copper wire thru all orifices.

The carb only has a low speed adjustment and its set to 2 turns out.

THe mower starts VERY easily. The engine runs smoothly.

The engine does not hunt for engine speed

The reason i found that it was running on one cylinder intermittently was when mowing heavy grass it acted like it was down on power and puffed black smoke as the governor engaged. When i pulled the plugs to check, one was only warm while the other was hot.

Figuring i had a bad coil (spark was intermittent on the RH plug) i replaced the coil with a brand new one. Coil gap is set at 0.010". I now have good spark on both sides, but plug on the RH side is still staying "warm" in the engine. I know im getting intermittent fire because i can hear "putt putt" sounds in the exhaust. These go away if i unplug the RH spark plug.

Ive rotated the spark plugs and the problem stays on the RH side. Ive checked spark, both using a plug and a spark tester, and there is lots of spark on the RH side.

Pulling the RH plug wire when the engine is running makes essentially no change, pulling the LH kills the engine.

I should add that both plugs are getting very carbon fouled with a short 3-5 min run. Of course the LH plug is worse than the right. Neither plug smells like gas.

Compression is 120PSi on both cylinders.

I pulled off the valve covers and checked the lash. LH side is in spec 0.006 In, 0,009 Ex. Right side is a little out of spec at 0.0085 In, 0.010 Ex. Would this 0.0025" out of spec cause my problems? I dont think it would, but i'll fix it if necessary.

I cranked the engine with the valve covers off and all valves are opening and closing smoothly.

After my last run of the day, when i shut off the mower, i noticed white smoke coming out of the carb. There was alot of smoke and it lasted for 1-2 minutes.

Could a plugged or partially blocked intake or exhaust (muffler) cause these issues?

THe only other thing i didnt check was if the flywheel key was sheared. Ill have a look at that tomorrow.

I think ive tried everything i can think of and still no joy

Thanks in advance.
 
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  #2  
Old 05-28-09, 07:09 PM
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I've never seen a blocked intake or muffler drop only one cylinder, With everything you have already done and the right side valve specs being a little out I believe I would pull that head. These engines were known for popping out valve seats, It's possible one is loose and seats under cranking speed but not at running rpms.


Good Luck
 
  #3  
Old 05-28-09, 08:30 PM
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Thanks for the quick reply, Ill pull the head tomorrow and pop out the valves and have a look.

On another forum ive read where Briggs had a problem with defective coils out of the box. Has anyone else heard of this issue? Any ideas what models of coils were effected? The new coil i installed was a model 394891. It was a different design then the factory original coil.

Any idea why the plugs are fouling so quick?
 

Last edited by jasonmargeson; 05-28-09 at 09:04 PM.
  #4  
Old 05-28-09, 09:13 PM
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Yeah, the plug fouling thing is what's got me too. Have you tried a new air filter or no filter for testing?

On the carb, the plastic main jet housing that drops down into the bowl.... is it black or white? I have one right here doing the exact same thing. I know it's the carb because I can swap a known good one on it and it runs just fine. I have cleaned the carb so many times I'm about to wear the screws out, but it still does it. I haven't figured it out yet, but I know it's something in the carb on mine. It's on one of my mowers, so it's on the back burner right now since all my time is spent fixing other peoples' mowers right now. I wish I could tell you exactly how to fix it, but I haven't gotten that far yet. (this is the first one I've encountered behaving like this).
 
  #5  
Old 05-28-09, 09:37 PM
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The carb in question, has no plastic in it IIRC. THe float is circular brass. The only jet is brass can be accessed thru a plug on the side of the carb. Its mounded on the side of the center bore at the bottom of the bowl. The jet has a allen head socket in it (not flat head).

Ive tried removing the filter > no difference. THe filter and pre filter are both very clean anyways.

The thing thats really confusing me is that both plugs are ending up fouled. That makes me think its running rich on both cylinders. But then you look at the fact that one cylinder is runing hot (well normal running temps) and the other one is just above ambient temp??? Yet outside the engine theres lots of spark?? Its almost like its not getting enough fuel in the cylinder. When removed the plug isnt wet, like youd expect if it wasnt getting spark at all. Thats why i thought it may be a blocked intake.

THe smoke coming back out of the carb after shutdown concerned me too. Was this unburned fuel from the intake or cylinder burning off?

Would a defective carb cause a machine to run on only one cylinder?

Throw in the fact that the machine is running smooth and starts like a dream and im lost.
 
  #6  
Old 05-28-09, 09:49 PM
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Oops, sorry I was thinking OHV V-twin engine. I didn't look at the model# well enough.

Have you tried adjusting the mixture screw IN 1/2 turn or so? I don't think you have an intake problem. I think you either have too much fuel due to a leaking needle valve or carb adjustment, or possibly a valve seat problem.
 
  #7  
Old 05-28-09, 10:08 PM
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Originally Posted by cheese View Post
Yeah, the plug fouling thing is what's got me too. Have you tried a new air filter or no filter for testing?

On the carb, the plastic main jet housing that drops down into the bowl.... is it black or white? I have one right here doing the exact same thing. I know it's the carb because I can swap a known good one on it and it runs just fine. I have cleaned the carb so many times I'm about to wear the screws out, but it still does it. I haven't figured it out yet, but I know it's something in the carb on mine. It's on one of my mowers, so it's on the back burner right now since all my time is spent fixing other peoples' mowers right now. I wish I could tell you exactly how to fix it, but I haven't gotten that far yet. (this is the first one I've encountered behaving like this).
cheese I would still be interested in hearing what you find out and is yours a briggs or kohler?
I know of a craftsman with a 20HP I think twin OHV briggs that has similar problems but is intermittent.
Also we sent a 25HP Kohler on a welder, back to kohler and they replaced the carb. It was better but still didn't seem all there to us but had to let it go that way.
 
  #8  
Old 05-29-09, 06:02 PM
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Yesterday i would have sworn that the new coil was working fine.

Today, im not so sure. After checking the needle and float in the carb ( it was a little sticky so i cleaned it up, now its fine). I also noticed a hairline crack in the aluminum where the main jet screws in. The threads of the jet are 1/4" deeper than this cracked area, so i doubt that extra fuel could be getting past and causing my issues. Just to be sure though, i removed the jet and put sealent on the threads.

I set the idle mix to 1.5 turns out.

After that, i thought id check the spark again with my trusty spark checker.

Left side has lots of blue spark.

Right side ( the side thats been giving me fits) starts firing ok, then it gets intermittent after 4-5 seconds of cranking. I get spark once every second or 2 compared to the rapid, multiple sparks per second on the left side!!!

Im checking the spark, with both spark plugs removed from the engine, with only one side grounded (thru the spark tester) at a time. I assume this the correct procedure?

Needless to say im ticked. THis was a brand new coil and cost me $105 after tax Plus it sent me down the path chasing other things that wernt the problem.

Now i figure its running rich, because the engine is drawing in enough fuel for 2 cylinders, but only running on 1.

Ive read other places that briggs had a problem with these 394891 coils being defective. Can anyone confirm? Has briggs released a revised model?

Now i get the pleasure of trying to convince my dealer that the coil was DOA. This should be fun. Wish me luck .

If a different coil dont fix it, i guess ill have to tear into the head and check the valve seats.
 
  #9  
Old 05-29-09, 07:35 PM
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Originally Posted by jasonmargeson View Post
THis was a brand new coil and cost me $105 after tax

Duuude.....Where on earth did you buy that coil ???


Buy Repair Parts - Briggs & Stratton

You need to make a post here; Ripoff Report: By Consumers, For Consumers

That is a good part number as shown above.....
 
  #10  
Old 05-29-09, 08:53 PM
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That's what I was thinking! It's a $50 coil. Yes, they had more problems than most of the other briggs coils, but not to the point of being a "problem part". Sounds like yours is bad though. Did you buy an original briggs part?
 
  #11  
Old 05-29-09, 10:14 PM
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Thanks for the replys.

Yes its factory briggs.

This is one of the joys of living in canada, our prices are wicked high on stuff like that. I only wish we could get Amazon type prices up here. Canada Post KILLS us with shipping costs.You hardly ever see "free shipping" on anything.

Even if i brought it up from the states, your typically looking at close to $30 just at the border in brokerage fees (if shippped Courrier).

I called around. Sears price was around $83 +$6 shipping, but it would have to come from toronto, and sears is SLOW sending parts. I waited for 3 weeks for a drag link to come from toronto.

Other local dealers were mid $80's too, but not in stock.

Only one local dealer had it in stock, price was ~$93 +tax, so it wasnt totally out of line with the other stores.

I was wondering about the coil because what would be the chances of a new coil being DOA? And my original coil was dead ON THE SAME side and behaving the same way? Just strange thats all...
 
  #12  
Old 05-29-09, 11:40 PM
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It is strange. Have you tried with the kill wire unplugged just for giggles?

BFHFixit...sorry, I forgot to answer in my last post. It is a 26hp briggs OHV twin that is giving me the carb problem. Same carb as your 20hp OHV. I don't know when I'll get the chance to work on it again...probably winter.
 
  #13  
Old 05-30-09, 07:08 AM
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No i didnt try unplugging the kill wire, because i felt if i was having a problem with the kill circuit, it would kill both cylinders, not just one. I should have tried it anyways, but the coils uninstalled now and ready to go back to the dealer today hopefully.
 
  #14  
Old 05-30-09, 08:50 AM
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Originally Posted by cheese View Post
It is strange. Have you tried with the kill wire unplugged just for giggles?

BFHFixit...sorry, I forgot to answer in my last post. It is a 26hp briggs OHV twin that is giving me the carb problem. Same carb as your 20hp OHV. I don't know when I'll get the chance to work on it again...probably winter.
No worries cheese, just the guy has had this problem since almost new. He has had sears out and they did all the suspect things and he has gone so far as to rig a fuel can on a rear carrier for his fuel tank and now has gone out and bought a kabota tractor

Just an FYI that would be nice to know of a solution to.
 
  #15  
Old 05-30-09, 07:53 PM
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Thankfully the dealer exchanged the new coil for another one. Will install tomorrow and post results.
 
  #16  
Old 06-01-09, 04:16 PM
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I installed the "new" coil.. RH side is totally dead

I didnt have time to do much troubleshooting, but i tried unplugging the coil kill wire.. made no difference.

This coil came new in new style briggs box, but it looked like it was very slightly used. THe parts guy assured me it was new and just got bumped around in the box. I dont know.... This was exactly what i wanted to avoid when buying a new coil instead of a used one. I dont know if the "new" one was defective in the box or if i have some other issue.

Is there anything im missing on that engine that could cause my problem?????

It has magnetron ignition, the only parts to it are the coil and the flywheel, as far as i know. Is there any other components to the ignition that could be causing me spark only on the RH side and not the Left?
 
  #17  
Old 06-01-09, 05:10 PM
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OK,

Just some basics here;

Standing on the right hand side (from seated position) of the tractor installing the coil, Are you installing it with the plug wires coming out of the coil to the rear of the tractor (to your left) ?

Are you setting the coil to flywheel air gap with the flywheel magnet in front of the coil at 0.010" or any business card thickness ?
 

Last edited by 31YTech; 06-01-09 at 05:28 PM.
  #18  
Old 06-01-09, 06:07 PM
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Yea where the wires come out is facing towards the seat.The coil is facing correct AFAIK. Its marked on the coil (this side out and this side towards cylinder)

I was setting the air gap to .010". This last time i set it to.014" as per the briggs check sheet. What setting is better?
 
  #19  
Old 06-01-09, 06:32 PM
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Anywhere between the two is fine, This one has me stumped as well. There is nothing to this system but the coil and flywheel magnet with the kill lead disconnected.

I have read about (never seen) weak magnets on other engines but wouldn't think that would only kill one cylinder.

I checked service bulletins but none pertained to only one cylinder firing, But all stated to replace the coil if no spark was present with the kill lead disconnected.... ?

Have you tested for spark with a plug held to a engine ground area ?

Is the battery fully charged and spinning the engine over well ?
 
  #20  
Old 06-01-09, 07:31 PM
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This coil fires both plugs at the same time, so if one side is not working there is a good possibility that the problem lies in the lead wire or plug connection.

Have you tested for spark on the dead cylinder and do not have any?
 
  #21  
Old 06-01-09, 08:13 PM
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Thanks for the replys guys. This isnt my first time around a engine, and this one is giving me fits too.

First, im grounding the spark checker to the aluminium fins on the RH head.

Ive used this same ground to check the LH plug wire (with the newest coil), and theres spark. This tells me that the ground location is good.

Plug lead looks good (its a brand new coil / wire assembly). Theres a solid connection between the tester and the lead.

Battery is fully charged.

I have tested using a plug with the old coil. With the same results as the Lisle tester. I havent tried a plug on the new coil yet.

Just a FYI im using a lisle tester like this Amazon.com: Ignition Spark Tester: Home Improvement

Remember, its been the Rh cylider thats been giving me problem from the start. It would be too much of a concidence that 3 seperate coils (2 brand new ones) would be having trouble firing the RH cylinder. So it HAS to be something else.

But what can it be????? The coil fires both plugs, so if it was a magnet problem, then neither should fire. Plug wire is brand new. Ground is ok. Gap on the tester is set at .020. Plug was set at .028.

The flywheel magnets appear plenty strong. When i was installing the coil they grabbed ahold of it and pulled it in pretty firmly.

This briggs is making me want to repower with a Honda
 
  #22  
Old 06-01-09, 11:26 PM
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This doesn't make sense. If it's firing one coil, it should be firing both. Is there more light on the right side, possibly making it harder to see the sparks on the plug or tester? How fast is the engine turning? Is it slow, as in a run down battery, or is it clipping along pretty good when cranking? There are only three components.... the flywheel magnets, the coil, and the plugs. The flywheel magnets are good. The coil is good. are you using RJ19LM plugs?
 
  #23  
Old 06-02-09, 06:28 AM
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OK. Lets go back to the beginning.
"When i pulled the plugs to check, one was only warm while the other was hot."
This tells me that 1 plug was doing all the work while the other was doing almost nothing. First thing I would have done is replaced the "warm" plug. It doesn't take much to "foul" a plug. A piece of carbon stuck between the firing tip & ground tip will cause intermintent firing or no firing. The coil is NOT your problem. Problem is either the spark plug or carbureation.

Back when I was snowmobiling, I ran into this problem all the time. 1 coil firing 2 cylinders- engine runs on 1 plug.
Solutions (in order of what fixed it most often).
1). Fouled spark plug.
2). Carb adjustment.
3). Thoro carb cleaning, including making sure the float does float and is set correctly.
4). Blown head gasket.
5). Sucking air. In your case it could be sucking air around the carb/intake area or maybe around the pcv area.
Very rarely was it fault of the coil.
 
  #24  
Old 06-02-09, 08:00 AM
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Cheese, I agree, It dont make sense.

Lighting is about even on both sides of the machine. Ive even checked the LH spark, with the tester mounted on the RH side and i can see it fine.

Engine is winding over fast. Engine will start (and run on one cyl) n a second or 2 of cranking.

Plugs are factory briggs (champion i think). I dont have the specs, but they were recommended by the dealer.




Indy, i have to agree that it cant be the coil.It doesnt make sense.This is the second new coil.

When i was troubleshooting, i swapped the RH and LH plugs side to side to see if it was a plug issue. After swapping the previously "dead" RH plug came back to life and the previously live LH plug died

I went to using a tester so i would be sure that i had a good ground for testing and i could eliminate any carbon fouling issues.

Carb is clean, i just cleaned it.

Floats needed adjustment, so i adjusted them level to the top of the carb.

Needle was sticking a bit, and the seat was dirty, so i cleaned. Moves free now.

There really is no adjustments on these carbs. Just idle speed and low speed mix.

I think the head gasket is OK. Im getting 120PSI on both cylinders.

I installed new gaskets on the intake, I also used sealent to be extra sure id have no leaks.

I know it shouldnt be the coil, but logically it almost has to be. Problems with the carb or headgasket would cause running issues, but wouldnt be causing my spark issue.

If i ever get this spark thing figured out, i dont think ill have a flooding issue since all fuel will be getting burned.
 
  #25  
Old 06-03-09, 01:21 AM
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Is the defective plug wire getting pinched between the metal shields?
 
  #26  
Old 06-03-09, 06:34 AM
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I still say go back to the carb. Soak it for a hour in a soaking carb cleaning solution. Gunk has a 1 gallon w/dipping basket for about $40 avaiable at most auto parts stores. Make sure to remove ALL adjusting screws and the main jet. Soak the main jet, too. Rinse everything off and blow out ALL holes in the carb with compressed air from both ends of the holes.

I have had many come in my shop where the customer has "taken his carb apart and cleaned it" only to have no change. 98% of the time, they used spray carb cleaner. This does NOT work on the interior of the carb. After I do my carb cleaning, they run like new again.

And you can ask anyone here, Cheese, 31Ytech, 30yeartech, we all have at 1 time or another had to get into a carb a second time to re-check, re-set, and even re-clean cuz the engine just didn't seem to run quite right. And the second time around fixed the problem. What was the problem? Don't know for sure. Maybe 1 tiny spec of dirt got missed 1st time, maybe the seat wasn't 100% set right, maybe the float was off by 1/16", maybe I was in a hurry and rushed it.

And for carb parts, use only OEM parts. Aftermarket parts for carbs suck. And make sure the needle & seat is new.
 
  #27  
Old 06-03-09, 07:28 AM
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Even with the carb intake and fuel system removed, you should be able to test for visual spark. That is not to say that the carb may not still be an issue, just that it sounds like at this point of testing, fuel system should not be causing no spark on one side.

Only thing I can think of checking not already mentioned maybe is ohming the coil out.

31YTech posted in this thread http://forum.doityourself.com/outdoo...290v-as02.html how to test a coil. Kohler also has instructions on their site. At least it should tell you if the secondaries are the same or at least close...



additional thought: If you isolate the LH lead from ground so it can not fire, then test the right...same result?
 

Last edited by BFHFixit; 06-03-09 at 08:38 AM. Reason: additional thought
  #28  
Old 06-03-09, 08:28 PM
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First thanks for the suggestions.

Cheese: Ive tried the coil wires run thru the shield area and just free off the coil. Currently theyre free. Theres no where it can be getting pinched, theyre just laying on top of the RH cylinder head area.

Indy, before my first post, i soaked the carb in Kleenflo dip overnight while completely dissassembled, Then i ran a fine, soft copper wire through all the orifices. After that i used briggs carb clen thru all orifices followed with compressed air.. This thing is surgical clean.

Right now the fuel issue is secondary to the no spark problem. After we fix this spark issue, if im still having flooding issues, for sure i will rework the carb.

BFHFixit: I agree, i should be able to check for spark, regardless of my carb situitation.

THe majority of my testing has been with only one side of the coil connected to ground, so my prob,em is there either way.

I will ohm out the coil. Remember this is my 3rd (original and 2 new replacement) coils that are not firing on the RH side.


While at the John Deer dealer today, i picked the brain of a tech for a couple minutes. Like everyone here including myself, he was sure it was a coil issue, however after hearing that this was the third coil, he said that its not likely.

One thing he said to check was engine rotation. He said that these engines can run either way, and hes seen where theve run backwards with similar issues. I cant see how this could happen when you consider im using a electric starter (will a electric starter run in either direction?) but im going to look at that tomorrow.

I cant say for sure, but off the top of my head its rotating clockwise. Ill check and confirm.

Im going to feel pretty stupid if that turns out to be the problem.
 
  #29  
Old 06-03-09, 08:49 PM
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Direction of rotation is not your problem, A Briggs starter will spin in either direction but the starter drive will not engage the flywheel spinning the wrong direction.

I hate to say it, I read this thread at lunch time today then pulled a new coil from stock. Briggs doesn't address coil testing with a multimeter, I tested for spark from both wires then ohm'ed it out and wrote the specs down. I then left them on my work bench.....

Will post the specs tomorrow......
 
  #30  
Old 06-04-09, 09:04 AM
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Originally Posted by 31YTech View Post
Will post the specs tomorrow......

OK Jason,

Test leads on both plug wires should yeld 2.76 ohms.

Open circuit between each plug wire and the lamination and kill lead terminal.

Kill lead terminal to lamination 9.0 ohms.


Good Luck
 
  #31  
Old 06-06-09, 07:50 PM
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31YTech: thanks for the reply. I had my doubts about the engine rotation myself.

Sorry ive been slow in replying, I ve been busy doing landscaping lately and hope to have a look at the coil tomorrow.
 
  #32  
Old 06-08-09, 04:42 PM
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31YTech: my coil checked out a little different than yours.

Kill term to ground/laminations:0.06 ohm
Plugwire to plugwire (end to end): 4.85 kOhm
Plugwire to ground/lamination : open.

Both the new and old coil checked out the same.


But, we now have SPARK~~!!!!

Im not sure what i did, but its working. I removed the flywheel to check the keyway and reinstalled, now theres spark.

Only thing i can figure is that the coil gap wasnt staying where i set it because one of the set screws was partially stripped (i didnt really catch this earlier).

I drilled and tapped for a larger screw, now its staying tight.

I bought some inline testers to confirm and all looks good!!!

THats the good news, heres the bad.,

The plugs are still fouling, and theres 1/4" of gas in the bottom of the intake.

THe RH plug is still getting warm and the LH is getting hot (but both were sparking, at least according to the tester). I took some pictures to illustrate the fouling issue but it dosent look like i can post pictures here. THese were brand new plugs today.

The previous crack in the main jet housing has now turned into a chip missing. I used sealent on the threads, so i doubt theres gas getting by, but it doesnt look pretty.

I think the next thing im going to do is remove the muffler and check for any obstructions unless theres some other thing to check.

Edit: heres a link to the pictures if theyll help Image hosting, free photo sharing & video sharing at Photobucket
 
  #33  
Old 06-08-09, 06:01 PM
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Well,

It's definitely running way too rich, Either the float valve isn't seating or the float has fuel inside. The level is too high or it's sucking too much fuel through the busted main jet boss.

Does the sealer you used on the main jet expand with the aluminum carb body as it warms up to maintain a positive seal ?

In any case, I myself wouldn't be wasting time with a busted carb, I'd replace it and be done.


Good Luck
 
  #34  
Old 06-08-09, 06:39 PM
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Originally Posted by 31YTech View Post
Well,

It's definitely running way too rich, Either the float valve isn't seating or the float has fuel inside. The level is too high or it's sucking too much fuel through the busted main jet boss.

Does the sealer you used on the main jet expand with the aluminum carb body as it warms up to maintain a positive seal ?

In any case, I myself wouldn't be wasting time with a busted carb, I'd replace it and be done.


Good Luck
Thanks for the reply. I take it the pictures worked for you.

I wish i could replace this carb with a new one. THis one is worn out. Its just that i really dont want to put much more into this thing . Its almost time to upgrade. Too bad it cuts great (even with the fouling plugs).

I used pipe dope as sealent. Its supposed to be gas and oil resistant, but who knows, . Im thinking about epoxying the jet in place, just to get it going.

In one of the pictures, you should see the fuel level. THis was the level after removing the float. I shook the float and it sounds empty.

Whats a new carb worth? If its anything like the coil, im sure ill overpay up here in canada.
 
  #35  
Old 06-08-09, 06:50 PM
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I would try some JB weld, I have used it on carburetors with pretty good luck.

You might also want to check the valve lash, particularly on the intake valves. Little to no clearance on intake valves can cause a rich running condition, but it certainly looks like fuel can get past your main jet.
 
  #36  
Old 06-08-09, 06:55 PM
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Thanks ill try the JB.

A quick glance on briggs parts and it looks like the original carb is no longer available, and the current model

CARBURETOR - 694026 (if thats the right one) costs $184 USD, which means itll likely be closer to 250 up here at the dealer.
 
  #37  
Old 06-08-09, 07:02 PM
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Check around with your local repair shops and see if they have a used lower body laying around, I have a few but it's a shame your across the border.....


Good Luck
 
  #38  
Old 06-08-09, 07:36 PM
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Originally Posted by 31YTech View Post
Check around with your local repair shops and see if they have a used lower body laying around, I have a few but it's a shame your across the border.....


Good Luck
Thanks for the offer. Ill try the JB first. If that fails ill look for a carb from a local repair place.

Ive been thinking, what should the main jet size be in inches (or MM). Im wondering if its not too large from years of people cleaning it improperly???
 
  #39  
Old 06-09-09, 03:07 PM
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I epoxied (JB) the main jet in and filled the chip behind the jet. Im going to let it set up overnight and hopefully try it tomorrow.
 
  #40  
Old 06-10-09, 04:45 PM
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Epoxied jet made no difference. Still flooding and carboning up plugs. 3/16" gas directly under carb in the intake.

Im going to look around for a used carb tomorrow, Might have to put the old girl up for sale it i cant find one. Oh well, no shame for a 23 year old mower.
 
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