Tohatsu 18 trolling speed-idle

[docksider]

I've been giving thought to getting a Tohatsu 18 for my 14' Smokercraft Alaskan. I do quite a bit of trolling for lake trout, so steady idle and slow speed operation are important.

I tried a friend's new 18 (his has remote control/steering) and found the slowest it would go on his slightly narrower 14 boat was 2.2 mph. That's a speed I often troll at, but I like and need the option of going slower.

What I wondered was whether a tiller steer 18 would like by able to idle at lower rpm. I assume that for remote, the last thing they want is a stall shifting into reverse. I know my slightly wider boat is likely to go slower b/c of its size, but I don't know if I can count on that alone. On the other hand, I don't know how many 20hp 2 strokes would every go slowly enough. My 15 hp Yamaha goes plenty slow when needed. Any thoughts?

thanks
dock

 

[John_S]

Re: Tohatsu 18 trolling speed-idle

I have the older 18hp 2 stroke vs the newer 4 stroke you are looking. I can say that my 18 is not a good troller at idle speeds.

I would expect the low idle rpm spec is the same from tiller to console. The main reason is the dog clutch (I suspect the 4stroke has it). A higher rpm would "bang" the gears, and not good for the lower unit.

As far as slowing the troll down, I think you can get a little by going to a little less pitch prop, but it will lower your wot top speed a little. Or add extra drag, such as those trolling plates. Others I know hook-up drift socks.

BTW, I think Alvin said the 18 will be a 20hp next season.

 

[docksider]

Re: Tohatsu 18 trolling speed-idle

Thanks for you thoughts.

Yes, I'd heard about the move to a 20. Should make it more competitive with Yamaha and Honda, at least in Canada. That extra HP might add to my concern about trolling speed. We'll see if others weigh in on this.
thanks

 

[TOHATSU GURU]

Re: Tohatsu 18 trolling speed-idle

The idle speed adjustment on both the tiller and remote models are the same. But, they are adjustable down to 850 to 900 RPM in gear. If you need to go slower you could change the prop pitch, change the tilt angle or add a few cases of beer(Increased boat weight = slower speed).

 

[docksider]

Re: Tohatsu 18 trolling speed-idle

Thanks for the reply. So the idle may go lower than my friend's was set at. And I can add weight, etc.

BTW, will the new 20 be based on the same engine as the current 15/18?

 

[TOHATSU GURU]

Re: Tohatsu 18 trolling speed-idle

That's what we have been told....But, they lie a lot

 

[docksider]

Re: Tohatsu 18 trolling speed-idle

Guess we'll watch with interest in January.
d

 

[mickjetblue]

Re: Tohatsu 18 trolling speed-idle

Remember that everything is somewhat tighter on a new motor.
I have had a Nissan 18hp for a few years now, having bought one of
the first 4 stroke models. After the first season, I needed to adjust
the idle up a little, due to cables breaking in, along with everything
else breaking-in. That was no problem, as the idle speed adjustment
screw is staring right at you when you take the cover off.

I have done a lot of trolling with it, at varying speeds, although I have
not checked speeds with a gps. My feelings about the motor are that it
is smooth running throughout its range, including trolling speeds. It
seems to like running at WOT, and for 18hp, that motor really kicks out
some power. I went to a 4 blade higher pitch prop for higher speed, and
that worked fine. The low end is still smooth. There are several props
available now, in case you want to change your load or speed range.
Use plus brand gas, and some occasional stabilizer to keep things clean.
This motor will do what you want it to do. Gas usage is unbelievably low.

 

[docksider]

Re: Tohatsu 18 trolling speed-idle

Thanks for your observations.

I'm still weighing whether to replace my Yammi 15 w/ a Nissan/Tohat 18/20 or my older 9.5 rude with a 9.8 N/T. If the former, the Yammi would replace the 9.5. Gotta have good trolling speeds on the boat with the larger motor, however this ends up.
dock