Incredibly smoky '90 115 Yamah***

[davidsinclair]

Good morning all!<br /><br />Yesterday on starting my 1990 115 (oil injected) Yamaha I was greeted with continuous, heavy oil smoke billowing from the exhaust vents just below the cowling. The motor was stopped and re-started five times over a twenty minute period and on the last start, the smoke returned to normal levels. Some wag joked about the fog rolling in as I idled about the harbour like an out-of-control smoke machine.<br /><br />While the smoke was pouring out, the remote oil tank appeared to become pressurised; on removing the cap it overflowed, whereas normally it sits at a lower level. Once the smoke stopped, the pressure in the tank seemed also to decrease.<br /><br />I've checked fuel lines for air leaks and am at a total loss. Do these remote oil tanks use crankcase air to pressurise like some Mariners?<br /> (I've been searching the forums and haven't found anything specific to this problem on a Yamaha). <br /><br />This motor is run weekly and is otherwise extremely reliable. Hoping this is something I can fix myself, and that someone will have an idea where to start.<br /><br />Many thanks in advance. <br /><br />-David

 

[Reel Appeal]

Re: Incredibly smoky '90 115 Yamah***

David,<br /> Not too familiar with Yamaha but,take a look at the oil tank.It should have a vented cap of some sort.Make sure it is not closed or restricted in some way.Another idea is there may be a one-way check valve in the line which is stuck open.I could be way off here,so please wait for more experienced advice....

 

[Capt Ken]

Re: Incredibly smoky '90 115 Yamah***

Sounds like the float sensor in the tank has malfunctioned and is over filling the tank. This will lead to the overflow going into the airbreather and thus into the lower cylinders via the carbs. Be sure the float on the stick isn't stuck and try again. Remove the float assembly and with someone having their ear close to the remote tank, listen to the pump in the tank. With the key on and the float at the lower level, you should get an alarm and the red light on the dash should flash. Slide the float up and the pump should turn on and further up the float should turn off. If not, replace the float assembly.

 

[davidsinclair]

Re: Incredibly smoky '90 115 Yamah***

Thank you Reel Appeal and Capt. Ken for your helpful advice.<br /><br />As it turned out, the float rod Capt. Ken referred to was somewhat pitted and seemed to be causing the float to stick. It's now nice and smooth. Apart from this the floats seem to be doing their job, switching the reservoir pump as intended to maintain a constant level.<br /><br />My next job is to work out why the yellow and red oil warning lights don't work! With both floats in the 'empty' position, the green light is extinguished and no alarm sounds. There's no voltage at the lightbulb socket. Looks like a trace-the-loom job.<br /><br />Again, my thanks to you both for your help.<br /><br />-David

 

[Capt Ken]

Re: Incredibly smoky '90 115 Yamah***

Ok, glad #1 problem solved, now for the rest. The yellow light is activated by the sensor in the remote tank in the boat and the red light/alarm is set off by the float in the engine oil tank. Now just so you know, if the float in the remote tank gets too low, it will shut down the pumping system and you will have to use the toggle switch on the engine to fill the engine tank. Your problem may be in the wiring or in the control module on the engine. Check first on the remote tank sensor to see if connection is made when the float gets low. Just remove the float and use a ohm meter to check between the two wires.

 

[vinney]

Re: Incredibly smoky '90 115 Yamah***

Im with Capt Ken .

 

[davidsinclair]

Re: Incredibly smoky '90 115 Yamah***

Thank you again gentlemen.<br /><br />The original problem was caused by intermittent operation of the 'control module' referred to by Capt. Ken. This had already been replaced on my engine, btw. <br /><br />In any case I replaced both this module and the engine tank float sensor, which resolved the issue. I will troubleshoot the remaining warning light issue with these known good parts. I'll be back for more advice if I get stuck.<br /><br />Many thanks for your help!<br /><br />-David