1994 Force 70, oil inside cowl

[cuda67bnl]

I recently bought an older pontoon with a 70 horse Force on it. The boat had been sitting for awhile and ran a bit rough the first time out, mostly not wanting to idle well. I could also see a bit of oil on the side of the motor under the cowl. I replaced all fuel lines, cleaned the carb, and rebuilt the fuel pump with new gaskets and diaphram and such. Also installed a new power pack as the old one had an intermittent problem. I also cleaned the motor of all oil and dirt. When I redid the fuel pump, I found a loose bolt back behind it, and one missing completely. I thought this might be where the oil was coming from. Motor is running great now once I adjusted the idle on the water. Spent all day Saturday at the lake and it never gave me any problems. When we left the lake at dark, I decided to pop the cowl off and see if any oil was back., and it was. Problem is, I can't tell where the oil is coming from. The fuel pump side of the motor had a thin film all over it, and it was pooling up in the bottom of the cowl. It also seemed worse than the first couple of times we took the boat out, before I worked on it. The motor is a 2 stroke and is not injected. Any ideas where the oil may be coming from? It was too dark to really see much when we were leaving. The oil seemed very black though. I know I have the idle mixture a little on the rich side, but I don't see where that would cause this.
Any help or ideas would be appreciated. I have the boat stored at the lake, so I can't check anything again until I go back to the lake gain. I also ran it on the hose for quite a bit before going to the lake, and never saw any signs of oil returning.....

 

[roscoe]

Re: 1994 Force 70, oil inside cowl

Black oil only on the starboard side?

I would be looking at the adaptor plate gasket.
Its under the powerhead.

Possibly when in the lake, there was enough back pressure to cause some of the exhaust gasses to leak into the cowl area.
If enough leaks in there, it can cause suffocation of the engine, and it will only run well if the top cowl is removed.

 

[tater76]

Re: 1994 Force 70, oil inside cowl

Three possibilities that I can think of....

As soon as you tilt your motor in full up position, you will get fuel out the front of your carbs that dumps into the lower cowl. The gas evaporates, and the oil is left behind. Some seem to do it more than others. If it is excessive, re-check your float level and make sure the needle seats properly. However, even then it can still happen while bouncing down the road to the marina or home. I just wipe it up every few trips.
If this is not the case, then proceed to check the three port covers on the powerpack side of the motor. One of these will have the fuel pump on it. Then again, if they are leaking you will have compression issues, and the motor will not run right.

There are also re-circulation tubes on the pump side, cant miss them they are small. These carry excess oil/gas back into the motor. One of your hoses could be cracked or loose. This would leave the black oily residue in the pan.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

Thanks for the ideas, guys. Yes, it seems mainly on the starboard side. I haven't tilted the motor, so I'll rule that out. I think I'll bring it back home this weekend and clean it up again, and run it some more on the hose or in a barrel and try once more to identify the leak if I can't figure it out at the lake. This is my first outboard, so I'm still figuring them out.

 

[jerryjerry05]

Re: 1994 Force 70, oil inside cowl

Check for air leaks around the fuel system.
A bottle of dawn soap and water will make bubbles if there is an air leak.
To check for a suction,use starting fluid.
I had a fuel pump leak only under a load.
The faster it ran the more it leaked.
Low rpms did nothing.
I rebult the pump,new gasket,diaphram and the gasket behind the pump.
Possible the recirculation system,the hoses need replacing?
You motor came with 2 different pumps.
Maybe a pic?
Profile,location? You might be close to someone who can help.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

I don't have a pic, but it has the square pump. I'll check the recirculation tubes on Saturday, and will likely bring the boat home again if I can't figure it out.

 

[pnwboat]

Re: 1994 Force 70, oil inside cowl

That loose and missing bolt behind the fuel pump was probably for the by-pass cover. There is a gasket under the cover. Maybe it's bad or damaged from running it while the bolts were loose/missing?? There are 3 by-pass covers. Each cover has 4 bolts that hold it secure. Might want to check the bolts on each of the by-pass covers.

 

[roscoe]

Re: 1994 Force 70, oil inside cowl

The thing that got me thinking exhaust side of the powerhead, was that he said " The oil seemed very black though."

So, how did the motor run? down on power? extra loud?

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

I don't have a manual for this motor yet. I've been looking for a diagram to know what those bolts were holding.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

The thing that got me thinking exhaust side of the powerhead, was that he said " The oil seemed very black though."

So, how did the motor run? down on power? extra loud?

Sorry, missed this earlier.....
Motor runs great. Doesn't seem loud to me.

 

[jerryjerry05]

Re: 1994 Force 70, oil inside cowl

He said the oil was on the pump side of the motor.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

Made it to the lake today, and brought the boat back home with me. I wiped off most of the oil this morning before launching. It's pooled up again, but I just can't tell where it's coming from. I'm gonna clean it up good, and try running it on the hose or in a barrel for a while. Probably gonna go ahead and just change the bypass cover gaskets as well.

 

[pnwboat]

Re: 1994 Force 70, oil inside cowl

Looks like the oil drops are hanging off the Bypass covers. Changing the gaskets would be a good bet.....maybe.

 

[tater76]

Re: 1994 Force 70, oil inside cowl

Looks like its coming from the re circulation fitting on the bypass port in third pic?

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

I believe the problem has been solved. This is what I found when I removed the top cover today...... I'm shocked at how much is missing. I'm gonna make a new gasket and see what happens. Many thanks to everyone who has offered help and advice. This really is a great site.

 

[pnwboat]

Re: 1994 Force 70, oil inside cowl

I would think that that would also affect engine performance too. I guess it would depend on how bad it was leaking. The cover seals the passage that feeds the fuel/oil mixture to the cylinder.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

The boat seemed to run just fine. Looking at how little gasket was left, I can't believe it wasn't leaking a hell of a lot worse than it was. I do have another problem though. My tach was working intermittently yesterday, and isn't working at all right now on the hose. I noticed my regulator looks like it may be burnt. I'm wondering if that is what is causing my tach not to work? I also had to swap batteries once yesterday, after being anchored for several hours with the radio running and the bait tank going. I didn't have to do that the last 2 times out.

 

[pnwboat]

Re: 1994 Force 70, oil inside cowl

A bad rectifier/regulator can prevent the battery from charging. From what I can remember off the top of my head, the gray wire from the rectifier/regulator is the tach signal. I would think that yes, if it is bad, it may affect your tach. I have to say that I've also seen my share of bad tachs too. Sometimes you have to tap on the tach to get'em to work.

To check the rectifier/regulator, all you have to do is to check the battery voltage on the red wire of the rectifier/regulator. Motor has to be running at a minimum of 2000 RPM's. You can do this either on muffs or in the water. Voltage should read around 13.5 to 14.5 volts. If not, you have a wiring problem, or the rectifier/regulator is bad, or the battery charging winding in the stator is bad.

 

[cuda67bnl]

Re: 1994 Force 70, oil inside cowl

I just did several checks, and it appears the regulator is likely shot. I'm not getting the readings I should be getting, from what I can tell. Without the tach working I can't confirm RPMs, but I revved it well over what I thought 2k should sound like and I don't show any increase in voltage at the battery. So I went ahead and ordered one.

 

[roscoe]

Re: 1994 Force 70, oil inside cowl

I believe the problem has been solved. This is what I found when I removed the top cover today...... I'm shocked at how much is missing. I'm gonna make a new gasket and see what happens. Many thanks to everyone who has offered help and advice. This really is a great site.

Yes, sure looks like you found the problem.

I'm still surprised at how black it is.

And there had to be a ton of fuel/gas running out of there to leave that much oil behind. That oil was mixed with the gas as it entered the engine. So if there is 2 ounces of oil in there, then there was 100 ounces of gasoline.