Oil slick everywhere I go...

Ok, here's the situation. Had a bearing go on a cylinder, had to replace the connecting rod, piston, ring bearing, etc. Have it all back together, seems to be running well (outside of needing new spark plugs), but now I have an oil slick everywhere I go, which wasn't happening before. I take the intake silencer plastic cover off the carbs, and the bottom carb has an oil/gas mixture dripping from it. This is where it is coming from it seems. You can see in the pics what I'm referring to. I know my guy took the intake off, linkage, etc....what could be causing this problem that wasn't a problem before? Looks to me like the linkage is fine, but I'm not completely sure what it SHOULD look like, if that makes sense. There are two hoses on the back of the carb cover on the bottom, and both are attached. Is there a possibility they aren't doing what they're supposed to be doing (whatever that is)? Also, I looked at the gasket for the carb cover, and it's in there. Soaked, but it's in there. It wasn't a problem before, but should I get a new gasket installed and see what happens? Thanks for any help guys. Attachment 365803Attachment 365805Attachment 365806

I should add that it's running a bit rough right now, but I attribute that to the spark plugs, since they're the same set in there when the piston burned. I assume it'll smooth out when the new set arrives. I guess if it doesn't, that'll tell me something I'm sure.

Here's what I found on another forum. I have a big syringe I can suck some of the oil out of the reservoir on the motor and lower the oil level, and see if it stays there. And I will also break the seal tonight and see how that works. I've had no problem with the oil res on the motor before, weird that I'm having one now. We will see how this works.

I have the same problem with my HPDI 175. It was the overflow tube that runs from the top rear of the oil reservoir down to the bottom of the air box. My cap on the reservoir does not leak and the tank is spotless. I recently discovered this problem and chased it down. My biggest fear was it could be an oil feed line and it would rob the powerhead of needed oil. I removed the airbox and there was a small puddle of oil around the overflow inlet. Case closed on mine. Problem found and it is not really a problem. However, I wish I could find out how to lower the oil level in the reservoir. It stays constantly at the top line to just above it.

Those lines that plug into bottom of the silencer (carb cover) are for oil overflow from oil tank under the cowl. There is a switch inside that sends a signal to remote tank when oil drops to a low limit. These can go bad and will pump unnecessary oil into carbs. That seems like your problem. I had a 130 years ago that did the same thing and that was the problem. This is the very same system used right up through the HPDI's. Good luck.

Thanks Reata, that's some good info there. I'm going to lower the level in the small oil tank on the motor, and clear the hose and see if that does it. Open the cap to break any seal. If that doesn't do it, then I'll have to investigate that switch. Is that switch in the tank? Or where is it?

Yes, the entire sender/switch that sits in the tank will need to be replaced. The level should sit between the arrows, so keep an eye on it.

I will take a look at it tomorrow, lower the level, and see how it goes. I see the switch and stuff is on the side of the tank, according to boats.net schematic.

Check your fuel pumps. If one or more are leaking, it can cause some of your symptoms.

Alright....took some oil out of the reservoir on the motor, got the level down a bit. It filled right back up to the top line, and the oil line coming from the top of that reservoir that goes to the carb cover is dry, so I really don't believe that's where the issue is.

I replaced the low pressure fuel pumps a few years ago, had the same problem on my Yamaha OX66 I used to own, so I was aware of the issues (motor was hell to start), and replaced em. Never been a problem, and see no leaks on that side of the engine.

There is, however, another line that goes into the carb cover, and it comes from the other side of the engine. The pic should show this line right above my hand/finger. What is this line's purpose? I greatly suspect this is where the problem lies at this time.

Attachment 366547

That line is a crankcase breather line that provides ventilation of any gases from the combustion chamber to keep from condensing in the crankcase. In a 2 stroke it is unlikely oil will blow through this line unless your oil injection pump is flooding the cylinders with oil. That is doubtful unless the linkage is broke allowing it to run wide open. More common to see oil blow by in a 4 stroke with worn rings. The line will be oily but that does not mean it is spewing oil. I would tie the line off in a vented container and run the engine a see what you collect if you think that is the problem.

Unbolt fuel pumps.

Pumps bulb and see if any fuel leaks. When fuel pump leaks, you will not see leak on outside of engine. You only see leak, when you unbolt pumps from engine.

Vacuum pressure from engine causes pump diaphragm to flex and pump fuel. When diaphragm leaks, vacuum sucks fuel into crankcase.

Did you figure out your issue? I have the same problem with oil leaking in the throat of the throttle body and leaking oil into the silencer cover. I have a 3.3 HPDI.

Thanks Reata, I think I will do that. I'm going to pull it out Fri and run it in the yard before I hit the lake and see if I can see where it is coming from, with the silencer off.
I haven't found the problem yet, but hopefully I'll learn something Fri, and the guy who worked on it says he'll be able to look at it Sun, so that could be good.
On a side note, when the throttle body was bolted back on, I checked the bolts, and two were missing, sitting in the bottom of the cowling. Several others were loose. He thought maybe because a bolt was missing, the motor was sucking in air, telling the computer to add more fuel, but I have doubts about that. I put them back in, tightened the others, and nothing has changed.

I just changed the fuel pumps not long ago, so I'm familiar with the low pressure pumps and diaphragms and whatnot, but when I had problems with them, the motor had a real hard time starting. It's starting up real nice right now, so I really doubt they're an issue, but once I see what I can see Fri with it running, maybe I'll investigate further.

I would run it on the lake with line in vented container. Only way to test properly to rule in or out that line you suspect.

You don't think it would do anything if I ran it in the driveway?

No way to get the sustained RPM’s in the driveway. If it’s going to act up it will be on the lake. They always run fine in the driveway:smile:

Good call. Here's some info from another site....

Although I don't need to tilt it for the leak to go out everywhere, I don't believe. I'll be looking at that this weekend if the weather allows.

You also mentioned needing spark plugs needing changed. Is the engine running rough? If you are getting incomplete fuel burn and tilt the engine you may get some fuel flow back out. The reason I was focused on oil was that generally the oil mix is so low typically most people would just call it a fuel leak.

So, I installed new spark plugs, problem went away. After a long day of running and fishing, the problem came back, and now after a couple more days fishing, the problem is back to stay. Really confused and angry now. Now what?

Some pooling of oil there is normal...my cover has been removed years ago.....I believe the covers had a drain tube not sure where it goes....on mine with no cover if its tilted up will leak the small amount of oil in the throttle body out to the lower pan

It's more than pooling, that's for sure. When there's an oil slick out the back of the boat, and there's standing oil in the splashwell, it's something bigger. I ran the motor while watching a few days back...couldn't see anything, where it was coming from, anything. Real frustrating. The hose that attaches to the bottom of the air cover though had lots of suction, so that was good to see. Although, it's not enough because there's still a mixture everywhere.