RPM limiting when oil is low

[mbarnesez]

I have a Yamaha 2 cycl 3 cylinder 70hp 2006 (Model 70TLR). When the oil gets low, if I tilt the motor an alarm sounds, level the motor and restart and alarm is silent.

Recently the oil got low, and I had to come home at 1800 rpm, with the alarm sounding. Adding power only caused the motor to shut off. I could rev the motor to 5000 in neutral, but not in gear. I got home, added 2 quarts of oil. Then when I went out, the motor hesitated at 1800, then the rpm climbed to normal levels. However, I then ran slow for a while and when I tried to accellerate a second time it was stuck at 1800 again. Again I had to come home at 1800 rpm, no alarm, and I could run to 5000 in neutral but not in gear.

I played with it at the dock, reved it up to 5000, did not really know what to do, basically waited. Now it goes up to normal high rpm's in gear or in neutral. But it still hesitates around 1800, as if it is deciding if there is enough oil or not before it will allow accelleration to higher rpm's.

My question is: Where is the rpm limiter that engages when the oil is low?
Can I clean it? Is there a switch in the engine? Is there a filter that could be clogged and cause the engine to think that the oil is low?

 

[waffles1]

Re: RPM limiting when oil is low

The alarms are there for a reason. If one is sounding don't run the motor until you fix the problem. Have you done a compression check on the cylinders since this happened? If you run the reservior dry or because it was in the tilt position you will suck air into the lines and may not get the proper lubrication for the pistons. Sometimes the air stays in and doesn't allow the oil to flow like it should. Is your oil level dropping as it should since this took place? i always carry extra oil with me in the boat just for this reason. Good Luck.