# Increasing oil level for 316



## Hoodoo Valley (Nov 14, 2006)

My John Deere 316 suddenly won't run below half throttle. Just dies. I went to mow and noticed my oil level was suddenly about 3 inches over the full mark. Figured the carb float was sticking, and took the air cleaner off to find the thing full of oil too. I was going to tap on the carb to see if the float was sticking, or the choke linkage slipped and was partially choking but wondered if the carb needed rebuilt. Been many years since I've rebuilt a carb, and any input would be awesome guys! Is it possible the float is just sticking given the suddeness of these symptoms?


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## jhngardner367 (Apr 5, 2011)

I would suspect 2 things of causing it.The first,would be dirt in the float needle/seat area. The second,would be a possible float sinking,from a pinhole,crack,etc.Try cleaning the floatbowl& needle/seat.Then remove the float,and shake it,to see if there's fuel in it.Usually,if there's fuel in it ,it will feel heavier,than normal,also.


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## Hoodoo Valley (Nov 14, 2006)

Where in the heck could a person get a kit for the carb of an Onan P43 series motor? This sounds daunting.....


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## jhngardner367 (Apr 5, 2011)

Yeah Onan parts ARE hard to find---AND expensive!I managed to find a carb kit for one at,of ALL places,an RV/camper dealer! They used Onan engines in some of the older RV"S.Also,some CASE dealers might be able to help,as they used the Onans in a lot of the Case/Ingersolls. Just give them the model/serial#,and hope for the best.


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## farmertim (Dec 1, 2010)

Hey Tractor Beam, I just did a Google search for Onan Carb Kit and came up with a few choices, I don't know if that will help.
Cheers 
146-0457 Repair Kit for Carb, Onan : A.S.A.P.

But what would I know I am just a dumb plumber from Australia?
Cheers:beer:
:aussie:


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## Hoodoo Valley (Nov 14, 2006)

Thanks Tim! I'm looking into them.


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## Mickey (Aug 14, 2010)

My first guess is the diaphragm in the fuel pump has got a hole in it. Since these pumps are driven by fluctuating crankcase pressure, any hole in the diaphragm can pull gas directly in to the crankcase.

As for parts, any Onan/Cummings dealer can supply. As for the fuel pump, a very common design for many engines of this type/size.


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## Hoodoo Valley (Nov 14, 2006)

Mickey said:


> My first guess is the diaphragm in the fuel pump has got a hole in it. Since these pumps are driven by fluctuating crankcase pressure, any hole in the diaphragm can pull gas directly in to the crankcase.
> 
> As for parts, any Onan/Cummings dealer can supply. As for the fuel pump, a very common design for many engines of this type/size.


Mickey, I replaced the fuel pump with an electric pulse attached to the frame a year or so ago. I drove a tapered pin into the hole in the block left behind but never felt good about thyat fix. I'm currently contemplating biting the bullet and rebuilding the original pump which has been on my bench for the whole time. I discovered pouring through my manual, that the original pump generated less than 1 psi whereas the electric replacement is about 5 psi, and I bgelieve that the barb is dirty to the point that the excess pressure is allowing fuel through into the oil. The engine began surging badly about the same time as all these other issues, so we'll start out with a bottle of B 12 chemtool and a rebuild on my original correct fuel pump and see what this does.


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## Hoodoo Valley (Nov 14, 2006)

So....... Fuel pump replaced in a nicely done fashion, added and extra filter in front of the pump as well as the carb, added an oil pressure gauge, and ran it for about 30 minutes mowing the 2 foot high lawn, and it began to smoke horribly all the sudden as it had before, when the crankcase fills up to the ventilator. What's my next move guys? Carb rebuild?


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## jhngardner367 (Apr 5, 2011)

check the crankcase breather valve to see if it's sticking/broken.


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## Hoodoo Valley (Nov 14, 2006)

So that breather is actually a valve? I always thought it was just a tube essentially. Why else would the oil level be coming up on the dipstick? I assume it's because the carb is letting gas in the crankcase through the rings?


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## HickoryNut (Mar 8, 2011)

it's a reed type valve TB pop the breather cap and give it a look


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## dangeroustoys56 (Jul 26, 2010)

Gas can leak in by the valves or rings - most my tractors wouldnt do that if i either rebuilt the carbs or do my 'shutdown routine- since id need around 10 rebuild kits- its not quite feasable financially( bills come first) - so i do the shutdown routine: turn the gas valve off, and run the tractor till the carb runs out of gas.

Breathers can be over saturated with oil- specially if the valve seals are worn - i have a 12HP OHV teccy that pukes oil thru the breather something firece-saturates the air filter- theres no gas in the oil tho. Its on my bench waiting for a tractor i can throw it on to thrash - ill probably make some sort of bypass for it, i wont waste any money on that motor.


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## Hoodoo Valley (Nov 14, 2006)

dangeroustoys56 said:


> Gas can leak in by the valves or rings - most my tractors wouldnt do that if i either rebuilt the carbs or do my 'shutdown routine- since id need around 10 rebuild kits- its not quite feasable financially( bills come first) - so i do the shutdown routine: turn the gas valve off, and run the tractor till the carb runs out of gas.
> 
> Breathers can be over saturated with oil- specially if the valve seals are worn - i have a 12HP OHV teccy that pukes oil thru the breather something firece-saturates the air filter- theres no gas in the oil tho. Its on my bench waiting for a tractor i can throw it on to thrash - ill probably make some sort of bypass for it, i wont waste any money on that motor.


Here's where I get confused.... I drained the oil, no gas seems present in the old oil. I fill it up with one quart of new oil which shows a half pint low. Run the tractor immediately and whithin a half hour it's smoking like a big dog, so I run it over to the shop and park it. I wait a half hour and check the oil and it's about 5 to 6 inches over the full mark and the air cleaner has oil pouring out of it. The engine does run fine though all the while. I'm bamboozled guys / DT! :dazed:


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## jhngardner367 (Apr 5, 2011)

*316*

DT,if this is a twin-cylinder engine,try this test. Start the engine,then pull off either spakplug wire,and see if the engine dies.If it keeps running,put the wire back on,then pull off the other side. If it dies,with either side,it means that that side may be pushing pressure into the crank case.If it keeps running after testing both sides,make a plate to take the place of the breather valve,with a 1/4" hole at the top.start the engine,andsee if it pukes oil : heavy spray/stream=bad rings,puffing/mist=normal(at idle + 100 rpm).Also,use a spray bottle of fuel,to keep the engine running,and shut off the fuel flow from the tank.keep it running for a couple of minutes,this way(you're bypassing the carb,with this test),then shut it off,& check the oil level.then open the fuel flow to the carb,and try a normal run,for the same length of time,& check the oil.high oil with flow to the carb=carb problem,high level bypassing carb=internal leak of engine.DO THE BYPASS TEST FIRST,THEN THE WIRE TESTS!


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## dangeroustoys56 (Jul 26, 2010)

Mine is a single cylender 12HP OHV teccy - 80's vintage , no fuel pump - PO plugged the vent into the air cleaner assembly- so i opened it up and after running a bit i noticed oil literally pouring out - took the breather assembly out and it was loaded with oil - so im guessing the valve seals are bad on it - i dont much care for that motor anyway.

TB- the oil would be like water if gas was in it. Im almost wondering if the breather is bad - like if its building up too much pressure..... does it have an oil filter? Wondering if you might have a bad oil filter......if it bypasses the oil thru the filter , it would be higher - then later might leak into it when its not under pressure.

Ive had a bad oil filter in my old truck once- knocked something firece when starting ( never did before) the couple times i ran it after - so put a new filter on it and never did it again - oil would be a 1/2 quart higher due to not filling the filter.


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## Hoodoo Valley (Nov 14, 2006)

Thanks DT! With your help guys I'm closing in on it. First off, I let it set after the overflow, and you could hear the oil bubling away as if boiling sort of slowly. Let it set a day and the oil went back down to normal. So! I'm beginning to think it might be the oil breather as you all are saying. DT, it doesn't have a filter on it never did. I need to study up on the breather now and then tear into it.


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## jhngardner367 (Apr 5, 2011)

Yeah,it sounds like the breather valve is sticking/plugged.Try taking it out and spraying it with carb cleaner,and GENTLY blowing it out(no more than 10/15 psi).


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## Hoodoo Valley (Nov 14, 2006)

Carb rebuilt and I looked at the breather and it looked as if brand new. Our local mechanic has suggested that the engine is shot, though it runs really good still. He said to rebuild the engine would be more than a new mower. He's coming to pick it up tomorrow for a look.


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## dangeroustoys56 (Jul 26, 2010)

Id just try a new breather valve . What if you tried to drill a tiny hole in the oil fill cap? Or leave it loose and see what happens ( if its the type with a long tube). Was there alot of oil in the breather area?


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## Hoodoo Valley (Nov 14, 2006)

dangeroustoys56 said:


> Id just try a new breather valve . What if you tried to drill a tiny hole in the oil fill cap? Or leave it loose and see what happens ( if its the type with a long tube). Was there alot of oil in the breather area?


The air filter area was flooded with oil. The breather valve was totally fine, just like new. I had the dealer pick it up cause this one has me bamboozled I tell you! Never seen anything like it at all, and I have no more idears!


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