1999 Johnson 115 Excessive Smoke at Startup

[Captain Jeff]

Last season I replaced the VRO/OMS pump, rebuilt all 4 carbs, rebuilt the primer solenoid and vapor separator tank. I also did a link and sync.

I usually take the boat out once or twice a week. I pump the primer bulb 3-4 times to get it firm. The boat starts right up but smokes a good amount. It will continue smoking until I pull away from the dock and accelerate a bit. If I idle it at the dock for 5 minutes, it seems to gradually smoke less but it is hard to say. The smoke is a bluish white.

The good news is that the motor runs great besides the smoke. It runs smooth, doesn't stall and has good acceleration. I have been using Pennzoil Marine XLF (Extended Life Formula Synthetic Blend) TC-W3 oil for the past couple years. I leave the oil tank cap loose because I don't trust the vent on it.

Any ideas? Thank you

 

[oldboat1]

sounds like it runs a little rich at idle when cold-starting. You might try adjusting the needles (2?) slightly leaner -- clockwise -- to see if there is less smoking. If cold starting is more difficult with the leaner setting, I think I would set it back to a richer setting and live with some smoke at start up.

If the primer setting is not in the running position, there would also be a smoking issue (similar to leaving a choke closed or partially closed). I don't see a primer solenoid for the '99 carb models, though -- might be looking at the wrong diagram. What is your model number?

 

[racerone]

A 1999 carbureted 115 has a primer solenoid.----Plain as day on the " fuel bracket " parts list.

 

[oldboat1]

Place the lever in the run position.

 

[Captain Jeff]

Thanks guys, I hope that is it. I thought I had it in the run position but may have nudged it when installing the air silencer or working on the engine. I'll check next time I am at the boat.

 

[Captain Jeff]

Well, the red lever was in the down position already. But I think I found the issue, just not the exact cause... When I pump the primer bulb on the fuel line, I can feel it get harder and hear some air venting by the vapor separator. However, when I look at the sight glass/fuel nipple where the fuel and oil lines come into the lower engine cover, I can see a good amount of air in the fuel line even after the bulb gets hard.

I am wondering if the motor is running at a very rich oil mixture at startup since the VRO may not be pumping adequate fuel for the amount of oil it is pumping. Then, once I get underway and the VRO gets a better prime, it is able to pump adequate fuel and the mix turns to the correct fuel/oil mix. I don't know how air is getting in the fuel line though. Any thoughts? Thank you

 

[Chris1956]

When the boats sits between runs, the gasoline in the 50::1 fuel mix in the carbs evaporates. This causes an oil rich mix to be in the carbs, when you first start up.

 

[Captain Jeff]

Thanks Chris, good point. Any idea about the air in the fuel line? I store the motor tilted our of the water. Maybe the floats drop as fuel evaporates and air gets in through the seats?

 

[racerone]

Would this extra smoke on start-up have anything to do with the recirculation system ??-----As you know oil drains off the parts to collect in the bottom of the cylinder crankcases,----Then on start-up this oil is put back in the cycle.----The extra smoke tells the experienced operator that all is in fact NORMAL.

 

[Captain Jeff]

I have had this motor for 12+ years and it never smoked this much on startup, that is why I was concerned. It is pretty heavy smoke and lasts for minutes. I'll try taking a video next time.

 

[Faztbullet]

Replace the cap on oil tank...common problem.