Where is all that oil coming from???

[hallhen]

Merc 75 7.5hp s/n 2813717. <br /><br />I have Oil in Drive shaft housing and prop area. I have change all of the lowere unit seals. Pressure and vacuum test or satisfactory.<br /><br />After a 30 -40 min. run there is what apears to be 3 - 4 oz oil oil/water in the prop area.<br /><br />So can anyone tell me were is all this oil/fuel coming from?<br /><br />Is this normal?

 

[Solittle]

Re: Where is all that oil coming from???

Yep! - The oil is from the unburned fuel.

 

[hallhen]

Re: Where is all that oil coming from???

I have had the carb check out and the mechanic say's it checks out ok. Although i do not trust this guy.<br /><br />It runs good at idle and high speeds<br /><br />I have new igniters and plugs. The stator wires are breaking down (strand loss with corrosion).<br /><br />Could this be the cause or is it the carb?

 

[profish00]

Re: Where is all that oil coming from???

ok did this test happen on muffes in the driveway??? or on the water?? if on muffs its normal for oil on the prop shaft expecialy after 45 min...

 

[hallhen]

Re: Where is all that oil coming from???

I am not familar with the term "muffes or muffs". <br /><br />If you are reffering to leaking oil. Inoticed a small amount oil right after i toke it out of the water. On another trip I noticed it on the driveway.

 

[Fouled Plug]

Re: Where is all that oil coming from???

On 2 stroke motors, there will be unburned oil in the exhaust from the fuel mix. It will drain from the exhaust area on the motor. Your 'problem' could be no problem at all. Keep an eye on the lower unit oil, and if it stays clear you are OK.

 

[profish00]

Re: Where is all that oil coming from???

muffs: The black thing you use to flush your engin with at the house with a garden hose, they are kinda like ear muffs for the outboard.

 

[andrewkafp]

Re: Where is all that oil coming from???

Smell the oil.<br />If it smells like gear oil (Distintive smell) it probabaly is.<br />If it smells like exhuast fumes or petrol, then it's unburned fuel. The only thing I find strange, is the amount from a tiny 7.5hp.<br />I have a 50hp Merc and run it every few weeks on the muffs(Winter over here) and after a few days it drips out a small qty of petrol/exhaust smelling oil. I am told that it is normal for bigger motors, as it sits in the exhaust tube and gradually runs out.

 

[hallhen]

Re: Where is all that oil coming from???

It does have a fuel/oil smell. The quantity may have been over stated. <br /><br />There is appx. 1 to 2oz of substance after it drains for 2 days. This is not including and potential mixture trapped in the lower unit crevasses.<br /><br />Also, fuel consumption appears to be high 1.5 gals/hour.

 

[andrewkafp]

Re: Where is all that oil coming from???

From what I have gathered on IBOATS, it's better to be running richer rather than leaner, so on a small motor,$ for fuel usage is better than burning pistons, besides, the fuel is only to be kept fo 6-8 weeks and then it should be disposed of.That's most likely the reason for the excess oil dripping.<br />NB I also run a 6hp Auxiliary motor and there are no muffs to fit a small motor like this, so I would imagine you would be running it in a tank.

 

[jdkzrt]

Re: Where is all that oil coming from???

IMHO, you have a problem. This is way too much oil to be loosing (on your driveway or in the lake)<br />1) check the oil level in the gearcase after a day on the lake. If it is low, this is where your troube is.<br />2) If gearcase is ok, and you have this much on the driveway, or in the water around your boat, you have a problem with your engine. Your oil mix is waaaayyyy too rich, or you have a fuel leak (oil/fuel mix is dripping, and fuel is evaporating).

 

[hallhen]

Re: Where is all that oil coming from???

jdk - The oil in the lower unit does not seem to change after a day on the lake. <br /><br />If the motor was running this rich I would have other problem like not able to reach full trottle and stalling, right?<br /><br />How much of a fuel leak should I look for?

 

[mellowyellow]

Re: Where is all that oil coming from???

from left field....clogged exaust perhaps?

 

[hallhen]

Re: Where is all that oil coming from???

I am not clear on how clogged exhaust ports would cause this to happen. Would the motor not stall?<br /><br />Although, I think all of us would be interested in hearing your hypothesis.

 

[jdkzrt]

Re: Where is all that oil coming from???

What ratio are you mixing your oil at?<br />Partial exhaust port clogging? Could be this also. Two strokes are extremely sensitive to exhaust flow, and maybe you have a carbon build up.This could give you a rich condition in one cylinder. You could try one of those spray type tune ups.

 

[cloumar]

Re: Where is all that oil coming from???

Hey Hallen,<br /><br />look at this post I made few days ago, you will find it in: Force / Chrysler Outboard troubles and the title is : Chrysler 8 HP - go there you will see that I have about the same problem as you and the answer is may be there for you also.<br /><br />Smoky

 

[hallhen]

Re: Where is all that oil coming from???

JDK<br />What ratio are you mixing your oil at? 50:1<br />Are you referring to the carb? <br />What type of cleaners would you recommend?<br /><br />Smokey<br />That was a good post on how collection drains. Also your description of the fuel/oil is close to my problem accept more of a golden color. <br />So I will run in the tank and look for leaks.<br /><br />Thank you both for your time…<br /><br />If I cannot find any than that is the nature of this 1970 vintage motor.

 

[hallhen]

Re: Where is all that oil coming from???

I put fresh oil in the lower unit and took it out for a day. No oil loss and no evidence of water in the oil.<br /><br />I also ran a tank test and could not find any leaks.<br /><br />The results are the same; after both tests oil and water are still coming out of the exhaust at the prop.

 

[roscoe]

Re: Where is all that oil coming from???

What you describe seems within the norm. But, since you have stated there seems to be excessive fuel use, you may have a small leak in your fuel pump. As fuel leaks thru a hole in the diaphram, it will run down and exit thru the exhaust leg of your motor. This could account for the "excess oil" coming from the exhaust.<br /><br />I would buy a fuel pump rebuild kit ($10) and put it in.

 

[hallhen]

Re: Where is all that oil coming from???

Roscoe,<br />I will try rebuilding the fuel pump. The motor is 33 years old and set for 17 years without runiing before I started it up in May.<br /><br />I had to change the all of the hoses and rewire it becuase of bad rubber/insulation materials. So, it is reasonable to beleive the diaphram could also be bad.<br /><br />I will report back once complete...