Another 2011 75 TLDI question. Fuel and oil consumption

I believe my 75 TLDI is using too much oil and fuel but I don't know what to compare it to. Prior to running the motor after I installed it, I drained the oil tank of any oil the previous owner had in there since I had no way of knowing what it was. I drained my onboard tank since it still had a few gallons of 50:1 mix in it. I added one gallon of the 100% synthetic Tohatsu 2 stroke oil and ten gallons of gas in the tank.

I have a 6” manual jack plate with the prop shaft approx 5 ½” below the pad. On plane, my plate is still somewhat under water but I figured I would bump up a little higher after I got a feel for the motor. Prior to heading out I checked for stored codes and there were none. After running throughout the afternoon, I returned home and checked for codes and luckily there were none.


Back to the set-up and how things ran. I have what appears to be a factory white 19 pitch Tohatsu prop and at WOT the tach read 5800 – 5850 which is at the upper range for my motor, correct? I was a little concerned when I was only able to reach 37 mph GPS. The motor sounded good at speed and didn’t seem to labor at all. I did notice that it ran rough at idle and through the no wake zones for what I had heard about the Tohatsu TLDIs. At one point I looked at my console sonar going through a no wake zone and it was shaking all over the place! I also noticed that when selecting the idle rpm with the key switch, the motor shuts off at the lowest setting. For that matter, it seems like it’s only stable at the highest idle rpm setting.


I ran approx 30 miles of Raystown Lake anywhere from 5000 – 5800 rpms and used up every drop of the 10 gallons of gas I had. When I got home, I pulled the cowl and was surprised to see how much oil I had used. I did mark the tank with the fresh gallon when I started and I’m about down to where the tank widens out on the bottom now. Again, that was with just shy of ten gallons of gas. I did run at a high rpm rate for an extended period of time but from what I had read and been told, the Tohatsu TLDI was a fuel and oil sipper.

I also noticed a light coating of oil on the majority of the components under the cowl when I pulled it off. I had everything wiped down and clean before I headed out so I wonder how much of my oil consumption was leaking somewhere. I didn’t see any obvious leaks when I inspected under the cowl.

I didn't pull the plugs and inspect them but aside form the slight roughness and stalling at the low idle setting, things ran pretty well. I don't know how this motor was treated before it came to me but I do know it has between 300-400 hours on it. Does this fuel and oil consumption seem normal? I don't know that I'll be able to afford the Tohatsu synthetic if I use a gallon for two trips to the lake.

Your engine should burn roughly7.5 gallons an hour at 70-75% throttle. Oil consumption seems very high,It should have been smoking like a chimney! I would do a compression test to evaluate condition of rings

I had very little smoke either on the water or with the muffs prior to going to the lake. As a matter of fact, I let it run outside of the garage doors like I had previous motors and was shocked to actually be able to walk around and breath in the garage! I could only get a little puff of smoke when I bumped the throttle. I almost hate to do a compression test for fear of what I'll find but I guess that's my problem and my next step. If compression was out of wack, would it have ran as strong as it did? Well as far as the fuel consumption I guess I shouldn't complain. I spent the majority of time running over 70-75% throttle and I started with 10 gallons. I know I ran well over an hour total so I guess time will tell but maybe I'm okay there. Just oil leaking under the cowl? I hope?

I seen low compression engines run fine,as long as readings are pretty even across the board. They just don't have the torque of a new engine.

Your owner's manual is online at http://tohatsu.com/tech_info/own_man_pdfs/Toh_40B2_50B2_75C2_90C2_115A2_003-11075-E.pdf
The WOT RPM range for the MD75C is 5150 - 5850.
Fuel consumption for the 75C2 at 5850 should be about 6.9 GPH. See http://tohatsu.com/tech_info/fuel_consumpt.html
At (or near) WOT, I would expect the system to use maybe a pint of oil to that 7 gallons. Certainly less than a quart.
The motor should idle OK at 700, 800, or 900, but might get a little rough at 700 for a long time. If it will only idle at 900, something is not right.
I would definitely check the plugs. Also reset the TPS initial setting.
One thing odd is the oil under the cowl. Definitely worth investigating what that's happening.
Have your dealer check the date of original sale of the motor. If it needs repair, it may still be under warranty.