# b&s 461707 flooding



## chappycg3 (Feb 27, 2016)

My b&s model 461707 is flooding. I have completely rebuilt the carb, new fuel line and filter. Still flooding. I even bought a brand new carb and it didn't help. Thinking maybe the new carb was faulty, I rebuilt it to no avail. It has done this in the past and a rebuild always fixed it. It started after raising the rear of the tractor maybe 2 feet in order to change a broken belt if that gives anyone any ideas. I am stumped on this. Maybe a slightly longer needle? Silicone the top to the bottom rather than using the gasket? Thanks all!


----------



## AVB (Nov 28, 2014)

Double check the gasket position that is that seals the upper body. They only work one way and causes the float to hang when installed upside down by rubbing on the float hinge. Also invert the upper body with float installed and make it is parallel to the gasket surface. When reinstalling the upper body to the lower body invert the carburetor as to not hang the float during assembly. Once assembled pressure test to check that float valve is working as intended before installation.


----------



## chappycg3 (Feb 27, 2016)

How do I pressure check it? I even bought the b&s repair manual for the thing - not much help there.


----------



## chappycg3 (Feb 27, 2016)

Just snapped these pics... The gasket will only go on one way so I know I have that right


----------



## AVB (Nov 28, 2014)

Could have provide the Briggs repair manual for free in PDF format for that opposed engine. The pressure is call a pop off test. It you apply approximately 10 PSI to fuel inlet with the carburetor inverted to make sure the float needle valve assembly is sealing. If you continue to add pressure the float valve will unseat and won't re seat until the pressure drops back to around 10 psi. It is test not mention in the manual though.


----------



## chappycg3 (Feb 27, 2016)

Performed the pressure test. Needle is seated.


----------



## AVB (Nov 28, 2014)

Now you got me stumped. We got to be missing something simple here.


----------



## chappycg3 (Feb 27, 2016)

I know! I put a shutoff valve on the fuel line so that I can run the carb dry before shutting it off. That's the only way it will start the next time. If I'm running it and shut it off for whatever reason without shutting the gas off, it will NOT start again unless I pull the gas soaked plugs, crank it for a while to get the extra gas out, etc. When it is running, you can tell it's getting too much gas. Maybe lifting the rear caused something? Doesn't seem like it though....


----------



## chappycg3 (Feb 27, 2016)

I have burned up 2 starter gears trying to figure this thing out


----------



## Treereaper (Jul 10, 2011)

Is the fuel line exposed to heat, it could be adding excessive pressure to the fuel intake?
Is the carb sitting level so that the float is level when it shuts the fuel off?


----------



## chappycg3 (Feb 27, 2016)

I don't think there is a problem with heat on the fuel line, but there does seem to be an issue with the intake manifold where the carb mounts to it. Snapped these pics... It is not level in 2 of the 3 pics with the level in different positions. Should I try grinding off some material to make it level?


----------



## Basementgeek (Feb 7, 2005)

No on the grinding, mowers are designed to cut slopes.
Still think you have a needle/seat problem.

BG


----------



## chappycg3 (Feb 27, 2016)

Good point. I didn't think it looked like it was off that far but I have no clue what else to try


----------



## SABL (Jul 4, 2008)

Pretty much what BG says.......being level doesn't come into the equation. Also, what is being used as a reference point in regard to being level?? If you are using the garage floor as an indicator of level, it shouldn't be the case. Minimum slope on a garage floor is 1/8" per foot with the slope heading towards the overhead door.....1/4" is even better. 

Forget the 'being level' part......the biggest question is if the surface is perfectly flat and even. In all reality, the intake is not the problem......if it were you would be seeing a 'lean' condition when trying to start the engine. 

If the carb is working as it should, you might want to check out weak spark. Seems like you've done everything but check out the ignition.


----------



## chappycg3 (Feb 27, 2016)

I have actually already replaced the ignition system as well. Getting a very good looking spark. I used to be able to mow my entire lawn on one tank of gas. After it started flooding all the time, I can only get about 3/4 of it done before having to add gas. I don't even turn the mower off while filling the gas tank anymore - cuz it will not restart. I used to be able to drop the throttle all the way down while dumping clippings from the bagger, but now if I do that it stalls and won't start again. I can throttle it down about halfway now.


----------



## Basementgeek (Feb 7, 2005)

Are you sure you have the linkage hooked up correctly? A hot engine should not need
choking or priming. If the coke is not all the way off, it will run too rich.

Maybe try another new plug, they are cheap enough

BG


----------



## Treereaper (Jul 10, 2011)

The carburetor out of level would have to be fairly extreme.
Is the air filter clean?
It's highly unlikely it will be the needle and seat on two different carburetors.


----------



## chappycg3 (Feb 27, 2016)

I have even tried running it with the air cleaner removed. While flooded, when trying to start it, fuel shoots out the top of the carb.


----------



## Treereaper (Jul 10, 2011)

Is there a fuel pump?


----------



## chappycg3 (Feb 27, 2016)

Yes. Vacuum operated diaphram (attached directly to the carb base so it is brand new also)


----------



## Treereaper (Jul 10, 2011)

If it's shooting fuel into the breather you could be looking at a bad valve.


----------



## chappycg3 (Feb 27, 2016)

I had also run a compression test. Both cylinders were very close if not identical. Don't remember the number right now, but I want to say it was 125ish psi


----------



## chappycg3 (Feb 27, 2016)

Ok, here's the current situation... I decided to try to clean out the sump and adjust the governor thinking that maybe a piece of gunk got stuck in it. Now it starts, spits and sputters for a while, then revs out of control. When it does this, I have no control over the throttle using the throttle cable. I can manually feather the throttle lever though and keep the rpms down. What am I missing?


----------



## AVB (Nov 28, 2014)

Redo the static governor adjustment...Sounds you miss adjusted it. Carefully read the instructions in the manual on doing this since you have the service manual.


----------



## chappycg3 (Feb 27, 2016)

Ok... I followed the instructions carefully and apparently I was doing it wrong. Instructions say to hold the throttle wide open, but I don't have to hold it cuz it's already there. At rest, the throttle is wide open. Something tells me it's not supposed to be?


----------



## AVB (Nov 28, 2014)

These opposed twins uses a governed idle so yes throttle will open when the engine is at rest.

The it the governor that you must hold CCW fully.

From service manual:


> 1. With governor lever nut loose, push governor lever
> counter-clockwise as far as it will go (wide open
> throttle) and hold in this position.
> 2. Rotate governor shaft counter-clockwise as far it
> ...


----------



## chappycg3 (Feb 27, 2016)

I watched a video on YouTube and saw how it is done. On that video, everything went clockwise. Apparently this engine is CCW. Here's what happens - I loosen the 7/16 nut, using a 1/4 nut driver, I hold the governor shaft with CCW pressure, but the lever is already as far as it will go CCW. Only way it will move is CW and it is held there by a spring. The manual says that the throttle spring pulls the throttle open and the governor pulls it closed. Is my governor gone? I'll pull the thing apart this weekend and see how it looks


----------



## AVB (Nov 28, 2014)

> I watched a video on YouTube and saw how it is done. On that video, everything went clockwise.


Probably the video was on a V-twin and not an Opposed engine. Yes a V-twin goes CW where an Oppose goes CCW on the governor cross shaft.


----------



## chappycg3 (Feb 27, 2016)

I think it was too. The fact that you have move the lever to WOT threw me off. It's already at WOT and is held there by a spring so the only movement I can make to the governor arm is clockwise. Is it possible for the governor to "break" so that it doesn't work correctly?


----------



## chappycg3 (Feb 27, 2016)

I just finished rebuilding my first mower engine. It's an older (early 90s) single cylinder B&S and that thing runs absolutely perfect. This thing has me stumped


----------



## AVB (Nov 28, 2014)

If don't have a copy of the service manual for this engine you can download a copy from my Google Drive.

Twin Cylinder L Head Briggs Service Manual


----------



## chappycg3 (Feb 27, 2016)

Yeah, I have the actual manual, had it for a few years. It isn't too user friendly. I've finally figured out exactly which set of instructions pertain to my engine specifically. When I pulled the bottom off the engine, the governor was not attached to the post. The retaining spring let loose for some reason. If the governor was not in it's proper place, would that cause the flooding problem? Or COULD it is a better question.... I currently have the engine on the bench. Valve covers off. I'm not positive about where the manual means by 1/4" past TDC. With the piston down approximately 1/4" I could not get the specified gap between the lifter and the valve. If I turned the engine further, I could get it though. I had it running after replacing the governor, but it sounded like there was metal occasionally slapping. So here I am now.... How can I get this thing spinning fast enough to simulate running so that I can figure out the metal slapping sound? The governor looks like it is still in it's proper place and honestly I think it might be the arms on the governor (the thing was a serious PITA to install). Unfortunately, to get it running after replacing the governor, I still had to really feather the throttle and it didn't seem to run right - still too rich. I'm not gonna give up on this thing, I know that it can be a good engine. I immediately beat the crap out of that 14.5 hp that I just rebuilt clearing out field grass for my 2 acre food plot. Sharpened the blades and mowed my lawn with it and it is begging for more! If I thought it would handle the larger deck, I'd consider putting that engine with the other deck!


----------



## AVB (Nov 28, 2014)

Double check cam to crank timing as you should be able to check the valve adjustment as describe. Having to turn the crankshaft further sound like the timing off by one tooth. Engine will run but just not right.

I had old 12.5 hp L-head that I actually got a little more hp power out of by shifting the timing by one tooth years ago but engines are not that forgiving nowadays with the automatic ignition timing advance.

You will not able to turn fast enough as you can't stablize the internal parts with the crankcase apart. All you can do is slow turn it though looking possible contact areas. Also it metal to metal contact you see where it has hitting as there will be impact damage showing.


----------



## kbowley (Sep 23, 2009)

You have an engine that is both running rich and flooding when shut off. That said, there is but one, and only one, way gas can enter the engine and that is via the carburetor. You governor merely adjusts / maintains engine rpms and will not cause a rich mixture or gas leaking into the cylinder.

The only way gasoline can bypass the carb is via a leak at the float or the integrated pump leaking into intake when setting. This will only happen if the fuel system is gravity fed, meaning the fuel tank is higher than the carburetor.

With the machine assembled, remove the fuel line to the carb and check flow...gravity fed will flow, a rear tank will / should not.

Remove the carb from the intake and set it off to the side and watch for fuel leaking out through the bottom of the throat or elsewhere.

In summary, excessive fuel is entering the engine when running and is leaking while setting. This points to the carb / pump and nothing else

let is know your findings after repairing the governor and reassembly to proceed.

Kevin,
Kevins Small Engine Service,
South Berwick ME. 03908


----------



## chappycg3 (Feb 27, 2016)

Finally finished up rebuilding the thing. Man, makes me appreciate those single cylinder engines! Got it back on the mower and tried starting it. No spark. Probably damaged the stator heating and pounding on the flywheel to get it off. I knew I was running the risk, but it was either that or scrap the thing. Haven't gotten around to testing it yet though.


----------



## AVB (Nov 28, 2014)

:facepalm:

Sounds like you are killing that poor engine by doing delicate surgery with a BFH and total lack of knowledge of how these engines work, even with a written service manual at hand. Boy I feel like ing for that engine.

With the right tools you don't need to pound on the flywheel which is a :nono:. I never had to in seven years of professional servicing these engines though I have applied considerable force on the puller sometimes but is a tapered setup and should pop off without heating. BTW I have been servicing equipment all my life since I was around 6 yrs old and I now 57. Yes my apprenticeship started before I even started school. My step father was an auto mechanic and started training me early. 

As for no spark now after heating the flywheel the stator has noting to do with that it only provides voltage for recharging the battery, power the lights and possibly energize an electric PTO. Your dealing with a magneto ignition system. It is magnetically driven.

First you need to check that flywheel magnets are still good and strong for the magneto. These are NOT the internal magnets that power the stator. If they are strong then disconnect the ignition coil pack kill terminal to see if know have now spark. Hopefully it is just that kill terminal is grounded by short and that you didn't applied 12v to the kill terminal :nono:. Applying 12v will instantly destroy the coil's electronics as there no safety built in to prevent this. Also if one of the spark plugs is shorted it will disable the spark on both plugs these oppose twins.


----------



## chappycg3 (Feb 27, 2016)

Well I am normally very patient with these kinds of things. After hours of using the puller and pulling threads out of the flywheel, I just wanted the damn thing off of there. I got this thing for free so I'm not out anything. The entire mower damn near got pushed down to the road for some scrap hauler to pick up. I'll pull the plugs first and see if there's a problem there. I double checked all of the magnets inside and outside of the flywheel and they are all solid. I set the gap between the flywheel and the coil at .012. I'll double check that also and probably take it down to .008 or so


----------



## chappycg3 (Feb 27, 2016)

How do I know if the magnet is still strong? It still attracts metal objects well. Disconnecting the kill wire from the coil armature doesn't fix it. Still no spark. I just replaced the coil last fall


----------



## chappycg3 (Feb 27, 2016)

Ended up putting a new coil on it and it runs like brand new now. Well, after having to also replace the choke cable cuz it froze up and broke on me with the choke closed (of course). So in the end, I still have no idea why it started flooding in the first place. I like doing this stuff so that I can learn how these things operate. Oh well, fresh rebuild and cleaning up all of the gunk that was sitting in the bottom seems to have fixed it. Thanks everyone for your help!


----------

