V-Twin Briggs exhaust glowing red on one side

Good point on the head gasket.. could of been the problem all along..

Willis I have had engines blow a head gasket and still have enough compression to run

matt-man wrote:

Willis I have had engines blow a head gasket and still have enough compression to run

This happens frequently. Only need a wee hairline rip in the gasket, and it'll do all kinds of bizarre things. And still run (crappy).

Doc Sprocket wrote:

This happens frequently. Only need a wee hairline rip in the gasket, and it'll do all kinds of bizarre things. And still run (crappy).

i didnt think it would. learn something new every day

Not sure if the twin carbs run off to different jets or what but one side running lean

Marines2621 wrote:

Not sure if the twin carbs run off to different jets or what but one side running lean

the carb on my kohler command twin is a single carb, jut a normal one, normal jetting, with a manifold going to the cylinders

I am pretty sure they are running on the same jet but I am not sure I have never worked with one of these carbs before

fairly certain its single jet

Get Doc back in here he would know

I can research further, but generally speaking, it's like this: When a carb feeds into a manifold, the resulting mixture gets drawn by the individual cylinders through a common runner. In other words, if the mix coming out of the carb is lean, it should be lean on both cylinders, as they both share a common source. This is regardless of whether the carb has 1 barrel, or 4. The general exception to this would be a high performance automotive arrangement. A square-bore 4-barrel on a "highrise" manifold like a Holley, has TWO individual runners within the manifold. This allows 2 barrel to feed half the cylinders in the engine, and the other 2 barrels feed the remaining cylinders. Alternate to that is bike and sled engines and the like, that use an individual carb to feed each cylinder.

It should be obvious, really. Looking at the carb and manifold very carefully, you should be able to see the path or paths that the mix follows to the cylinders. If need be, you can post up a few pics of your setup. In the meantime, post your model/type/code, and we'll see what we can dig up.

i had that issue with mine and all i did was replace the gaskets on the carb and it stopped it. What happens is the Cylinder that is glowing red is getting more air and less gas so its running hotter. The cylinder on the other side would now be getting more gas so it would be running cooler than normal.

I rebuilt my carb and there are two jets in it, with two individual intake runner going to each cylinder. There are two "barrels," in the carb that feed the intake.

I found a TON of carbon built up around one of the valves on the right cylinder head (the one that ran cooler). I've been cleaning it every once in a while and ordered new head gaskets for it too. I've got to get this thing back together soon because I'm moving into a house I just bought in NH at the end of October. I don't want to lose any parts in the move!

My model # is 407777
type # 0167
Trim: E1

Thanks,
Mike

I would still throw a brand new head gasket on and see if that fixes your problem

I would reseat the exhaust valve on the hot side and see if that causes any difference. also I would snag a new head gasket and clean out both the carb and the intake manifold. if after that it still is hot check the coil and see if it is firing late. after that idk what to tell ya.

Have you made any progress on this? I did some further research and found that you have a model that I have not yet had the pleasure of playing with. Indeed, a 2-bbl carb and it does appear to have seperate intake runners.

That said, we're down to this:
*Carburetion issue on bad side
*Bad head gasket
*Bad valve/seat
*bad coil on bad side

Or something that I may be missing because I'm still on my first cup of coffee...LOL

Connect a spark tester on the bad side just to be sure it's getting a strong, consistant spark on that side. Do a compression test and compare the numbers from the 2 sides- they need to be within 25% of each other (NOT 25psi).

Very carefully inspect valves and seats, paying particular attention to exhaust valve and seat on bad side. It's probably worth your while to lap them while you're at it.

Inspect head gasket mating surfaces, and install new head gasket. Torque bolts to spec in a step pattern using a torque wrench.

Verify both main jets in carb match, and actually measure orifice sizes if you can.

This might have been addressed already- forgive me if it has... Has this engine done this as long as you've owned it, or is the problem new?

QUESTION: it it really loud and poppy when it runs or is it still quiet?

I would check spark, compression, and head gasket first

For some reason I stopped getting email alerts when people respond to my post so I figured it was a dead thread..

But THANK YOU to everyone for offering information.

I replaced the head gaskets- slight difference between exhaust gas temps. The valve seats looks clean and shiny. The cylinder head mating surfaces looked pretty good. I torqued everything down in sequence and adjusted the valves evenly to .004" (which I'm not sure is right).

The engine has done this since I bought it. It had a junk governor when I bought it. Someone on another forum expressed concern that the cam could be bad.

I rebuilt the carb before that- it runs really nice now, but has uneven exhaust gas temps. It is not poppy or loud when it runs now.

So I still have one side running hotter than the other. I checked for spark (just by eye) and I think it isn't consistent, which leads me to believe I may have a bad coil. Can I buy a tester that measures spark? I will run a compression test probably this Friday.

MCRideout wrote:

So I still have one side running hotter than the other. I checked for spark (just by eye) and I think it isn't consistent, which leads me to believe I may have a bad coil. Can I buy a tester that measures spark? I will run a compression test probably this Friday.

they DO make test lights for spark. you plug one end on your plug, and one end into the plug wire. in theory, it will allow the engine to run too, so you can tell.

I might have to pick one up this weekend. I was just thinking about checking the wires to and from the coils. Would those little wires affect the engine?

You can try cutting the wire close to the coil (spark plug wire) and running a new one.. if that doesnt solve it.. new coil time. Chances are that its the coil from it running way to rich on fuel.. aka not igniting and shoot the gas out the exhaust valve while still ignited.. What octane as are you running.. and is it visibly cherry hot all day or only at night?

I'll try that. I'm running like.. 87 octane. The left side is only barely visibly red at night while the right side isn't red at all. I have an infrared thermometer in my office at work so I'll take it home to check the exhaust temps. I'll compare it to my other tractor with a similar engine. I'm hoping big time it's a COIL as that's easy as pie.

I performed a compression test this morning before work.

Left side = 160
Right side = 120

New Head Gasket and adjusted valves. Looks like I'll measure the valve travel next. I'm thinking possible issues include...

bad valve(s)
bad cam lobe

Am I right? Could there be more?

MCRideout wrote:

I performed a compression test this morning before work.

Left side = 160
Right side = 120

That might be an issue. Right outta tha manual:

"Briggs & Stratton does not publish any compression
pressures, as it is extremely difficult to obtain an
accurate reading without special equipment.
It has been determined through testing, a simple and
accurate indication of compression can be made as
follows:
Remove both spark plugs and insert a compression
gauge into either cylinder (one cylinder at a time). Turn
engine over with engine starter until there is no further
increase in pressure. Record this reading. Repeat
procedure on other cylinder and record that reading.
The difference between both cylinders should not
exceed 25%. More than 25% indicates loss of compression in the cylinder with lower pressure."

The quick math says you're right on 25%...

that brings a bunch of things into play. lobes, cams, valves/clearances, rings, pistons... if you have a squirt gun for oil or a funnel with a tube or syrenge or something, try squirting a SMALL amount of oil in the cylinders. its called a "wet compression test". helps the rings seal better