Sick Yamaha 115hp 2 stroke needs a doctor

Yamaha V4 115hp 2 stroke, model# 115TLRQ, Serial# 392505, Code 6E5L is running very rough. I think the motor is in limp mode because it will start and idle rough but as soon as I try to increse speed the engine will die. Both outboard oil tanks (Large tank on back of boat and small tank on engine) are full but I have a red light activated on my dash that says low oil. How can I test to see if its a bad CDI Unit or test the sensors on the oil tanks to see if they are bad. There is no warning buzzer sounding which usually happens when I am actually low on oil. All I have is the red light on my LCD Marine Meter Yamaha. The red light is above the round circle that shows a low fluid level on it on the far left side of meter. The local back yard mechanic said that I should put a new CDI unit on and see if that works but that is a very expensive part.
Thanks in advance for any help you can offer!

Re: Sick Yamaha 115hp 2 stroke needs a doctor

When the motor is in limp mode it will idle PERFECTLY and run up to 1800-2000RPM PERFECTLY, just not over that. You have multiple problems here....you probably have a bad float switch, the light on but no buzzer is result of the bottom float switch being activated(due to bad switch) while the top
switch is also activated. The bottom switch is activated when the float goes all the way down see, but the top switch is activated when tank is full....it confuses the system....you need a new float switch assembly...see yamaha parts page at the yamaha sight for part number. But the running rough
at idle and below 2000 rpm is another problem entirely...probably carbs need to be removed, taken apart and cleaned CORRECTLY

Re: Sick Yamaha 115hp 2 stroke needs a doctor

I would look at the spark plugs first and then clean the carbs like yamatech said.
How old is the fuel?

Re: Sick Yamaha 115hp 2 stroke needs a doctor

+1 on above. I have the same engine. Sometimes, the plugs will look ok, but still need replacement. Cost: $8.00

With the 90/10 gas breaking down, it's just so easy to get gummed up needle valves on your carbs. They're easily cleaned/rebuilt, and you don't even need a carb kit if you're careful with the gaskets. You just need to make note of how many turns it takes to fully seat any adjustment screws, and put the adjustment screws back at the same place. I think the carbs need cleaned every couple of years--no matter if there is any symptom or not. Cost: Can of carb spray cleaner and 1 hour time. (I have a repair manual--good investment.)

Like it was said, you should get you a new float for the small oil tank. ($175) If the red light doesn't go out after changing the float on the small oil tank, move it to the big oil tank--same part.

The only problem I ever had with my engine was the small oil tank would fill up and overflow thru very small oil lines into the carb breather--into the carbs blowing smoke and running rough. The oil injection electronic module ($240) was the problem. Unfortunately, electrical modules are not returnable if they're not the problem.

Good luck!