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My briggs vanguard is having issues with oil coming out of the carb. It was overfilled so I changed the oil, and filled it exactly to the full mark. Now today after about 3 hours of use I have lost some oil (it is 3/4 of the way full now). Before when I throttled up it blew a puff of black smoke (which I can see is carbon) now after changing the oil it does not do this. It seems to be coming out of the throat of the carb and not the breather as I thought it would be. It leaks out on to the air filter and out of the air filter box. I have a few theories on what might be the cause. Could it be A) The gasket on the OHV cover is not sealing and it is getting sucked up via the hose that attaches from the cover to the fuel pump and getting sucked up in to the carb. B) It is the breather, not sure how to check this C) The Head gasket. I thought I would get some peoples opinions that have been doing this longer than I have before I throw money at it! Thanks for all the help in advance! :thanku:
 

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Sounds like the carb float needle is not sealing and contaminated the oil with gasoline which MAY have caused sever wear. If or when you get the other problem fixed, I would install an inline gas shut off valve and use it whenever the engine is not running.

Your other problem could well be a head gasket. Sometimes you can remove the valve cover and see it blowing in the push rod gallery which is where the leak will be.

Walt Conner
 

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If I read it right your saying there is oil in the carb and air cleaner when you take the air cleaner cover off after running the engine? If so it is most likely coming from the breather tube, this could be caused by excessive blow by from worn rings or valve guides, also the breather could be malfuntioning or in need of a cleaning. Since you said the oil level went down after use I would doubt that the oil is getting comtaminated from excessive fuel, noe way to check is to rub the oil from the crank case between your fingers and compare that to what new oil feels like, also does the crankcase oil smell like gasoline? (little gas smell is normal but you will be able to tell if its excessive). These are not the most scientific systems to check it but work pretty well without having an oil analysis done.

Brad
 

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Discussion Starter #4
I don't know where exactly the oil is coming from, but it is running out of the carb area and into the air filter and prefilter then out of the housing. It could be coming out of the breather, but I checked and the breather seems like it doesn't have any oil in the tube or the piece that covers it. Also none comes out while it is running. There also seems to be oil on the bottom left cylinder fins and linkage area, which lead me to think the OHV cover although that could be from the same leak. Some background on the engine is that it has 380 some hours and the meter does work. This is a recent issue as it didn't lose oil in the 40 some hours that I have had it.

Sounds like the carb float needle is not sealing and contaminated the oil with gasoline which MAY have caused sever wear. If or when you get the other problem fixed, I would install an inline gas shut off valve and use it whenever the engine is not running.

Your other problem could well be a head gasket. Sometimes you can remove the valve cover and see it blowing in the push rod gallery which is where the leak will be.

Walt Conner
It doesn't smoke at all so it shouldn't be too worn right? I don't have a compression tester but I heard you can rotate the engine backwards and tell the compression by how far it kicks back. I will be looking in to it more this weekend. Also I thought about the gas in the oil so I changed it quick, it didn't smell like gas and looked and felt like the regular oil (SAE 30) I use. I also have wanted to put a shut off valve in and will do so this weekend
 

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Discussion Starter #5 (Edited)
If I read it right your saying there is oil in the carb and air cleaner when you take the air cleaner cover off after running the engine? If so it is most likely coming from the breather tube, this could be caused by excessive blow by from worn rings or valve guides, also the breather could be malfuntioning or in need of a cleaning. Since you said the oil level went down after use I would doubt that the oil is getting comtaminated from excessive fuel, noe way to check is to rub the oil from the crank case between your fingers and compare that to what new oil feels like, also does the crankcase oil smell like gasoline? (little gas smell is normal but you will be able to tell if its excessive). These are not the most scientific systems to check it but work pretty well without having an oil analysis done.

Brad

How would you go about cleaning the breather? Or checking if it needs it? Yes the oil is in the air cleaner area, also there seems to be some on the linkages and left cylinder fins, but I can't say for sure until I tear it down this weekend. The oil does not smell like gas at all. Also Is it possible for the oil to even get out through the carb throat? There isn't really any symptoms of worn rings, no loss of power, smoking etc. But they still could be worn. I will provide a engine model number and such tomorrow and maybe get to work on it.

Edit- the engine #s are model 303777 type 0333-033898 code 92020311
 

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The only way oil can get out of the carb. is for it to come out of the engine past the rings, valve guides or through the breather tube. However because the engine is constantly drawing air into the cylinders it is uncommon for the oil to come back out the carb. unless there is a large quantity.
It almost sounds like there is an oil leak that is spraying oil on the air cleaner area and maybe drawing a little oil in while running?

Is there anyway you could post up a few pictures of what your seeing? There were a few variants of air cleaners on the Vanguards that I've worked on so it would be easier to see what your talking about.

Brad
 

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If you have an air leak into the crankcase (leaky valve cover gasket), it could cause enough flow from the breather to carry oil along with it. I used to have an intermittent problem with a V twin VG on a 4000 psi pressure washer, using 30W oil solved the problem. The air filter must also be absolutely clean, or it will tend to draw oil from the crankcase. I wouldn't worry about blowby past the rings, if the engine starts easily, the rings are OK.
 

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"It was overfilled so I changed the oil, and filled it exactly to the full mark. Now today after about 3 hours of use I have lost some oil (it is 3/4 of the way full now). "

"Since you said the oil level went down after use I would doubt that the oil is getting comtaminated from excessive fuel"

Well as a mechanic, you should know that the oil doesn't get overly contaminated WHILE the engine is running but when it isn't and that happens all the time resulting in blowing oil into the carb.

" I don't have a compression tester but I heard you can rotate the engine backwards and tell the compression by how far it kicks back. "

That really won't help you much in this case as it is an old B&S trick to see if an engine has enough compression to run. You need to do a blow down test to really tell leakeage past rings or valves on this engine. The problem is not valve seals. It COULD be the crankcase breather but I doubt it.

Walt Conner
 

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Actually almost all oil contamination occurs during operation, dilution would occur if raw fuel was making its way into the crankcase but it doesn't sound like that's the case. If it's using a excessive amount of oil without visible smoke and the fact that the poster states that there is oil on the cooling fins and other external parts leads me to believe that it may be an external leak. Pictures might help pinpoint the problem though, or at least make sure we're heading in the right direction.

Brad
 

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This is getting interesting!! I'm going with Walt,but first guess,I'd think breather,or valve seals.Some breathers you can clean(I have)but they say you should replace'em.Sorry ToomanyGt,only time I've ever had gas in the oil,it happened when sitting uncranked and entered via carb.needle & seat.Fuel Cutoff fixes that little ditty.:fing32:
 

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Discussion Starter #11
I will get some pics later this weekend, when I tear it down. Some of the reason I think it is the valve cover is that I adjusted the valves about 4 or 5 months ago but the seals looked good then, but I was thinking maybe they didn't seat right. I don't think it has been leaking all that time though as I would have noticed it. The engine starts in 2-3 seconds with the choke on and maybe about 7-10 seconds with it off. I will look in to getting a compression tester if it isn't something like a seal/ breather problem. I will be installing a fuel shut off as I wanted to anyway and I went and got one today so I will install that when I work on it. I should be working on it Sunday so I will have pictures then. Thanks for all the help so far guys!

@ Walt, how would you go about doing a blow down test?
 

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No hard feeling Dude, but I want to clarify that I never said that you could not end up with raw fuel in the crankcase from the engine sitting, it does happen if the carb is higher than the intake valve. What I was talking about was the difference between contamination between partially burned hydrocarbons from excessive blow by and deluded oil from raw hydrocarbons ( liquid fuel) from a leaky carb. Based on the op description it doesn't sound like he's having a problem with the latter while sitting. Unless I'm misunderstanding him which is also possible lol.

Fireman: I believe Walt is referring to a blow by or leakdown test, ***** will require special tools, but the leakdown test is simple, the tools can be bought at harbor freight, but will require a compressed air source. The blowby that actually measure the crankcase pressure with a vacuum/ pressure gauge, but requires a little more experience to read what you looking at, also on 2 cylinder engines it's harder to get a accurate reading due to the pulses. Hope this helps and goods luck with the diagnosing.

Brad
 

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Discussion Starter #13
No hard feeling Dude, but I want to clarify that I never said that you could not end up with raw fuel in the crankcase from the engine sitting, it does happen if the carb is higher than the intake valve. What I was talking about was the difference between contamination between partially burned hydrocarbons from excessive blow by and deluded oil from raw hydrocarbons ( liquid fuel) from a leaky carb. Based on the op description it doesn't sound like he's having a problem with the latter while sitting. Unless I'm misunderstanding him which is also possible lol.

Fireman: I believe Walt is referring to a blow by or leakdown test, ***** will require special tools, but the leakdown test is simple, the tools can be bought at harbor freight, but will require a compressed air source. The blowby that actually measure the crankcase pressure with a vacuum/ pressure gauge, but requires a little more experience to read what you looking at, also on 2 cylinder engines it's harder to get a accurate reading due to the pulses. Hope this helps and goods luck with the diagnosing.

Brad
I don't believe it is from sitting, as it hasn't overfilled itself yet, so I don't think it will. It could be a slow leak though, which is why I want to install a shut off valve. Since a leakdown test sounds a bit hard, I will save it for last, and check else where first. Can an engine have good compression and still have blow by? ie would buying a compression gauge actually help or should I just do a leakdown test?
 

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Look for something simple. When I had my rental business, I had a fleet of Vanguard engines, from pressure washers, large tillers, concrete saws, and generators. Never had the head off any one of them.
 

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On my VG, there is noticable oil leaking out from the breather tube. And a little around the valvecovers. Nothing for me to worry about, the oil loss is very little. I might have to add oil 1 time a season. I thought a puf of black smoke was carb. related, as in the needel jet may be dirty.
 

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"Actually almost all oil contamination occurs during operation,"

TooManyGT, I think you are trying to get a little too technical here. While diluted maybe a more accurate description, the introduction of raw gasoline into lubricating oil is a contaminate according to the dictionary and I doubt anyone involved here would question that. I notice in your first post that you also used contaminate. A leaking carb float needle does not necessarily occur every time the engine is stopped, may occure tomorrow or next month.

"Can an engine have good compression and still have blow by"

It is also typical of these engines in the early stages of head gasket leaking to have good compression, blow oil out into the air cleaner box and of course use oil. In these cases, the leak appears to be just a few pencil marks across the gasket from the cylinder to the push rod gallery. See my first post.

I don't recall you saying what the spark plugs look like though I may have missed it.

Walt Conner
 

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My Vanguard 23hp is doing the same thing.

It's at 240 hours. Oil in bottom of air filter. Oil leaking and visible on bottom left cylinder fins.

I started noticing maybe a tablespoon of oil on the floor, so I investigated. The cap on the breather unit has two screws and one was missing! (Note that I've had this engine since new and have never done anything to it other than regular seasonal maintenance.) So I completely removed the cap, cleaned it, and then screwed it back on with two screws. The rectangular ring gasket under the cap looked and felt fine.

It still notice evidence of leaking after I put it away. If I let it sit for 48 hours it will leave over a pie plate diameter of oil on the ground. I will be having someone take a look at it soon, and I'll post anything I learn.
 

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Discussion Starter #18 (Edited)
My Vanguard 23hp is doing the same thing.

It's at 240 hours. Oil in bottom of air filter. Oil leaking and visible on bottom left cylinder fins.

I started noticing maybe a tablespoon of oil on the floor, so I investigated. The cap on the breather unit has two screws and one was missing! (Note that I've had this engine since new and have never done anything to it other than regular seasonal maintenance.) So I completely removed the cap, cleaned it, and then screwed it back on with two screws. The rectangular ring gasket under the cap looked and felt fine.

It still notice evidence of leaking after I put it away. If I let it sit for 48 hours it will leave over a pie plate diameter of oil on the ground. I will be having someone take a look at it soon, and I'll post anything I learn.
Thanks! I think I found my leak, as I don't think it leaks while not running, Though I am not sure. I will be keeping a close eye on it though.

I think my leak was caused by a clogged breather in combination with not having a fuel shutoff. There was oil laying in the breather and not draining out through the hole that leads back in to the crankcase. It was indeed coming from the breather. This pic doesn't really show it but there is some oil below the valve covers and on the tin of the engine. (I also wiped some of it off before when it started leaking) I couldn't get a good picture of it due to it's location. I think I found out why it is on the lower fins/ linkages though. There was a screw missing from the cover that covers the breather and it was running through the hole and across the support and on to the fins/linkages. The linkages are right below the hole which was right where the oil was coming out of the air box at.(in the second pic you can see the hole) It may also be coming from the left valve cover as the gasket on it looks rather bad and I will replace it to be sure. I ran it for about a half and there didn't seem to be any leak so I am hoping it is fixed. Thanks for all of your help guys and I hope it stays fixed!


Edit the images do not appear to be working, so here are links.
http://imageshack.us/photo/my-images/225/dscf0012ve.jpg/
http://imageshack.us/photo/my-images/856/dscf0010rx.jpg/
 

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Discussion Starter #19
"Actually almost all oil contamination occurs during operation,"

TooManyGT, I think you are trying to get a little too technical here. While diluted maybe a more accurate description, the introduction of raw gasoline into lubricating oil is a contaminate according to the dictionary and I doubt anyone involved here would question that. I notice in your first post that you also used contaminate. A leaking carb float needle does not necessarily occur every time the engine is stopped, may occure tomorrow or next month.

"Can an engine have good compression and still have blow by"

It is also typical of these engines in the early stages of head gasket leaking to have good compression, blow oil out into the air cleaner box and of course use oil. In these cases, the leak appears to be just a few pencil marks across the gasket from the cylinder to the push rod gallery. See my first post.

I don't recall you saying what the spark plugs look like though I may have missed it.

Walt Conner
I honestly didn't look at the plugs yet, I should do that and see what they look like. I will look at the head gasket if it keeps leaking, I hope it doesn't though. Are head gasket problems common on these engines?
 
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