Tohatsu 115 TLDI low WOT rpm on new 2012 motor

[Bowen Gord]

Just bought a new 2012 Tohatsu 115 TDLI and I am breaking it in, but... It is very slow to come up to plane and the WOT is only reaching 4300rpm. I am running a 13.2 X 19 prop on a 17' Arima boat with perfect hull paint and no additional load. I was running a 1989 2-stroke 120hp motor previously with a 13 X 19 prop and had normal 5500 rpm WOT. The new motor starts and runs very smoothly, just limited on the "hole-shot" and WOT rpm. I have changed the fuel line to make sure there are no restrictions and no indicator lights come on. Any suggestions?

 

[pvanv]

Re: Tohatsu 115 TLDI low WOT rpm on new 2012 motor

Odds are you need a lot less pitch. Did the dealer (who is required to rig the motor) adjust the jack height correctly? The anti-ventilation plate should be about even with the bottom of the boat. Is the motor dead vertical when on plane? If not, the trim should be dialed-in better. Your dealer should be given the chance to correct the rigging, and maybe go for a ride with you to demonstrate that it's rigged properly.

 

[Bowen Gord]

Re: Tohatsu 115 TLDI low WOT rpm on new 2012 motor

Thanks Paul,

The rigging, height and trim all appear to be correct; once up on plane it rides and trims out really well. It does seem like the pitch is too much (it feels just like starting a car in third gear rather than first gear - no torque but lots of speed once you get going). The dealer is happy to look at it again but I'm in a bit of a remote location so it's not so easy to get there. I'll try a lower pitched prop first as that will be the easiest and sounds like it could be the issue. I'm not sure why the prop would be different from the old motor/prop combo, but maybe my old prop just didn't have the same level of efficiency or "bite" as the new props do?

Gord

 

[pvanv]

Re: Tohatsu 115 TLDI low WOT rpm on new 2012 motor

Gord,

Every prop is a little different, but more importantly, every motor/boat combo is different... even "identical" setups. If possible, get the dealer to go for a boat ride with you, and take a couple of props along. That will help you dial in the best match.

 

[Bowen Gord]

Re: update:Tohatsu 115 TLDI low WOT rpm on new 2012 motor

Re: update:Tohatsu 115 TLDI low WOT rpm on new 2012 motor

My local Tohatsu dealer got me set up with a new prop to try yesterday and that was all it took. I went from the 13.2 X 19" pitch to a 13.5 X 15" pitch and what a difference! The motor now hits the recommended WOT of 5600rpm and the top speed is 25% higher than with my old 120hp motor at the same rpm, even with the 4" less pitch. Interestingly the turning, porposing, and coming up onto plane are all much better than with the old motor as well. I may also raise the height of the new motor a little but I'll wait until I have installed trim tabs before doing that.

Thanks for the input!

Gord