Small Engine Repair/Troubleshooting

[warpedskydiver 0]

I have a Vanguard V Twin 16hp motor on my cub cadet.

It has started burning oil, it compression checks on both cylinders @110lbs/in.

What the hell is going on here?

Rings?
Headgaskets?

Something else?

I have replaced the plugs and oil filter/change and everything is fine there.

Both plugs had oil on them and were very fouled.

Anyone know what is happening?

[Broke 0]

could be rings, could be valves, could be head gasket although if the engine is liquid cooled I would doubt it.
Do you know what the compression is supposed to test as.
Does it smoke on start up? Then valves

Smoke all the time? Then rings likey

Divot your source for all things Hillbilly.
Anvil Brother 84
SCR 14192

[1969912 0]

The engine should have a crankcase ventilation system. Take a look at that first. There might be a clogged filter or bad check valve.

Doesn't sound like rings.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[warpedskydiver 0]

Air cooled....

Kinda like a PCV valve?

Thanks....I will check it right now

[warpedskydiver 0]

The oil is coming through the top end via the crankcase vent (PCV)

I cleaned it using non clorinated brakleen, made sure it moves (about 2mm?) and put it back on.

Same thing, oil coming through it and so it goes down the carb and gets burned, thus smoking like a mosquito abatement truck.

WTF?

replace the valve?

or what else is causing this?

[1969912 0]

  Quote

Air cooled....

Kinda like a PCV valve?

Thanks....I will check it right now

Yes, but it might not be called that. Might just be called a "crankcase breather".

Also, air leaks into the crankcase through a leaky gasket can cause oil misting which will end up going through the carb and burned.

The above is assuming the oil isn't overfilled of the wrong viscosity.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[lowpull 0]

you could have valve seats clogged with carbon.

try this

at initial start up, as soon as the engine smooths out a bit take a small squirt bottle with just plain old clean water, and squirt water into the throat of the carb with the engine about 1/4 throttle.

If there is a massive amout of carbon in the cylinders the water will cause the carbon to crystalize and just go out the exhaust.

I would also chech the muffler for blockage.

ralph

[1969912 0]

  Quote

The oil is coming through the top end via the crankcase vent (PCV)

I cleaned it using non clorinated brakleen, made sure it moves (about 2mm?) and put it back on.

Same thing, oil coming through it and so it goes down the carb and gets burned, thus smoking like a mosquito abatement truck.

WTF?

replace the valve?

or what else is causing this?

Is the tube between the vent and carb/air cleaner full of liquid oil?

What did you clean out?

Did it look like no. 8 in the attached pic? The tube connecting to the breather is no. 11. (this pic. is for horizontal-crank 16HP Vanguard)

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[DeNReN 0]

Is the oil level correct??

ie: not way overfull?

[dunesurfer 0]

Perform a cylinder leakage test. If you have excessive leakage past the rings to the crankcase, the pressure can force oil through the crankcase ventilation system.

[warpedskydiver 0]

  Quote

  Quote

The oil is coming through the top end via the crankcase vent (PCV)

I cleaned it using non clorinated brakleen, made sure it moves (about 2mm?) and put it back on.

Same thing, oil coming through it and so it goes down the carb and gets burned, thus smoking like a mosquito abatement truck.

WTF?

replace the valve?

or what else is causing this?

Is the tube between the vent and carb/air cleaner full of liquid oil?

What did you clean out? Did it look like the attached pic?

YES, it was partially full of oil.

I rechecked the oil level and it is perfect.

SAE 30 oil was used.

[1969912 0]

If you have a vertical crank engine the breather assy should look like no. 8 in this pic. The hose going to it is no. 11.

Also, the same numbers apply to my previous pic., which is for a horiz. 16HP Vanguard.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[DeNReN 0]

did this problem develop rapidly or over time?

how many hours (approx) are on the engine?

have you had to add oil to the engine?...how much per hour of running?

has there been any noticable loss in power or fuel economy?

details man details!!!

btw..I am not a small engine tech...and I did not stay at a Holiday Inn Express last night........but I am a master mechanic

[jm951 0]

valve guides could be worn. how many hours on the engine?

[warpedskydiver 0]

302 hours on engine, was a loss of power while mowing so I stopped, checked the oil.

It was a bit low but still on the dipstick.

So I proceeded to do the oil change and etc.

It started smoking lightly right about the time I noticed a loss of power.

Then it started smoking alot.

I found tonight that the oil was coming up the tube and there was enough oil coming up that there was maybe 10cc of oil collected on the air cleaner base plate after it had run only a minute.(I had cleaned it all off prior to starting it)

Until this happened on sunday the motor ran extremely well, never had to add oil before that.

[warpedskydiver 0]

horizontal crankshaft

[1969912 0]

  Quote

302 hours on engine, was a loss of power while mowing so I stopped, checked the oil.

It was a bit low but still on the dipstick.

So I proceeded to do the oil change and etc.

It started smoking lightly right about the time I noticed a loss of power.

Then it started smoking alot.

I found tonight that the oil was coming up the tube and there was enough oil coming up that there was maybe 10cc of oil collected on the air cleaner base plate after it had run only a minute.(I had cleaned it all off prior to starting it)

Until this happened on sunday the motor ran extremely well, never had to add oil before that.

Oil in the air cleaner means that your breather is flowing OK. It sounds like something is trying to pressurize your crankcase beyond what the breather is designed for. That would be bad rings or a bad head gasket. The facts that it started suddenly and that your compression isn't too bad makes me think it's not rings. Vanguards are known to blow head gaskets, usually on the part of the gasket between the pushrod box and the cylinder. If that happens, combustion gas blows right into the crankcase. I read that you can usually see the leak by taking off the valve covers and starting the engine (might be messy).

Also, some people say that an air leak into the crankcase (which should be at a slight vacuum) will cause the crankcase to pressurize. Doesn't make sense to me, but that's what they say. A common place for a leak is at the dipstick tube seal.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[DeNReN 0]

hmmm...any noise that happened in the same time frame of before?

anything that didnt sound "normal"?

any noise that is related to engine...changes with rpm or load?

[1969912 0]

If you decide to look for a head gasket leak, here are a couple crappy pics showing where to look. I have no idea what it would look like, but any oil flowing past the leak would probably get misted by the gas flow. You may need to rev it up while looking, and may need to squirt some oil onto the area where it is supposed to leak.

Another way to check for a leak is by doing a compression leakdown test, but if it's a small leak, I'm not sure how fast it would leak at only ~100 PSI. It might not leak any faster than normal ring/valve leakage.

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[warpedskydiver 0]

No nasty noises, just loss of power and now running rougher, plugs started fouling with oil.

I would lay odds on the headgasket.

I used to work on cars and bikes when I was much younger (Dad was a genius of a Mechanic)R.I.P.

I am going to do the headgaskets, it is the least expensive and makes the most sense, with the cylinder pressures being equal and quite high I am doubtful it is the rings.

I wish I had everything in my life maintainence free

[warpedskydiver 0]

Thanks you guys have been a huge help.

I did not find a online schematic of this motor so was wanting to know what I was getting into before tearing the headgaskets off.

Thanks once again.

[warpedskydiver 0]

I will post the pics of the headgaskets.

[1969912 0]

  Quote

Thanks you guys have been a huge help.

I did not find a online schematic of this motor so was wanting to know what I was getting into before tearing the headgaskets off.

Thanks once again.

You might want to look closer just in case it's not the head gasket.

Here is a link to a parts diagram for what should be your engine. Enter your engine data just in case. B&S makes you buy repair manuals, but most parts diagrams are online.
http://shop.briggsandstratton.com/BShopProductListingPage.asp?MecID=100&CatalogID=56B2B9A7-283C-11D4-8886-00B0D0203414&SessionID=43C7B3A0-6A44-4EB2-B2CC-23B437198A68&SMSID=Smart+Search&ViewName=htsDIY&EngineModelNumber=305447&EngineType=0068

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

[warpedskydiver 0]

I will inspect before doing anything

Got any idea of the torque specs on the head bolts?

[1969912 0]

might be here:

http://www.briggsandstratton.com/miscpdfs/RNT/Engine%20Specifications%20Chart_ms3992.pdf

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG