Change Tohatsu 115hp to a 140hp?

[rickrod63]

Can a Tohatsu 2-stroke 115hp be changed to a 140hp? If so, how? I notice the bore, stroke, and displacement are the same on these motors.<br /><br />Thank you in advance, Rick

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

Yes, it can. Consult your local dealer.

 

[ziemann]

Re: Change Tohatsu 115hp to a 140hp?

rickrod-<br /><br />I would guess that since Elvin is a dealer, he can't ethically post that kind of info here. The 115 is a detuned engine....I am guessing the obvious would have to be done. Bigger carbs, intake, reeds, etc... Maybe a change in gear ratio? I would imagine it would need to be able to push out a great amount of exhaust as well. I would have to believe it would be a pretty involved project, but if the porting is the same, it is probably do-able. <br /><br />I have only owned smaller Tohatsu's- and am hardly an expert (Elvin is the Tohatsu god here)but I plan on purchasing a new 115 TLDI this fall when they become available.

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

It's a five minute, no parts needed change....Consult your local dealer.

 

[GWUISTER]

Re: Change Tohatsu 115hp to a 140hp?

I remember reading in Trailer Boats mag a few years ago a test of this motor. At the time they said (if I remember correctly) that the difference was in the carb linkage and that one carb was restricted from opening all the way. They were concerned that one cyl would run leaner than the rest under wot. Article said a small adjustment to the linkage and the motor would put out full power but would probibly void warranty.<br />HTH -greg

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

Not the carb linkage, but close.

 

[jshoes52]

Re: Change Tohatsu 115hp to a 140hp?

Maybe (probably) I'm wrong here, but if he does that, won't he possibly be looking at a new prop, too? With more power, he'd have to go to a larger prop to keep wot rpm's down, and probably sacrifice some holwe shot in the process. Seems like he'd gain only in top end speed at the cost of hole shot.

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

He would gain hole shot and top end. You have to look at what you are turning at WOT to see if you need to increase pitch.

 

[rickrod63]

Re: Change Tohatsu 115hp to a 140hp?

I need the additional power. Is there any cons or disadvantages to having this work done on my 115hp?

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

None. The only tools needed to do this adjustment are a pair of pliers and a rule. You are just bringing the engine up to what it is. Read the next line carefully. Good TIMING is almost as important as knowing when to STOP.

 

[rickrod63]

Re: Change Tohatsu 115hp to a 140hp?

Gotcha, remove throttle stop on the top carb and retime to 140 specs.

 

[ziemann]

Re: Change Tohatsu 115hp to a 140hp?

Wow- this site never seems to cease to amaze me. I learn something cool here almost every day. One stupid question Elvin....so often hp upgrades are prohibitive when you look at what often needs to be done. Am I to assume that the relative simplicity of this change is due to a Tohatsu cost saving measure- to minimize the number of unique parts that have to be in inventory? This just seems too easy....BTW, also Elvin, I wish I had a dealer close by that was as knowledgable as you....

 

[jshoes52]

Re: Change Tohatsu 115hp to a 140hp?

So, if that is all it is, how much more did the 140 originally cost than the 115? My 90tldi cost about $500 more than the 70 tldi, and then I find out all the parts are the same. The difference is just in the ECU. Can I have it re-programmed and get my $500 back? (rhetorical question)

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

It is a lot cheaper to build one engine...and detune it down to have another engine as well. All the brands have done it on some model at one time or another. Tohatsu just kept the modifications to a minimum to avoid unnecessary manufacturer costs. They still do it today, but due to the costs of the CPU's it's not cost effective to swap them out on a TLDI. Also, in theory it is a violation of Federal law to alter an engines hp...because in theory you are changing it's emmisions. Of course that's a load of crap, but who need's the headache. The 140hp was only $50.00 more than the 115/120...Now you know why. There is also an anti-knock sensor on the 140 that the 115/120 did not come with...Useless sensor in my opinion. I've never heard of anyone reprogramming a TLDI CPU. I'm sure it can be done, but that would result in the loss of the TLDI's 4 year warranty if Tohatsu found out. I really don't think it would be worth it.

 

[rysemus]

Re: Change Tohatsu 115hp to a 140hp?

rickrod63,<br /><br />If you see this could you email me at ric425@hotmail.com I have a few question on this topic

 

[Realgun]

Re: Change Tohatsu 115hp to a 140hp?

Elvin where do they sell those and can I get a cheap tohatsu 115?<br /><br />I need a repower and the 115 is a max for my boat actually 120 by the homemade calculation. And the 140 would do that at the altitude I boat at.

 

[TOHATSU GURU]

Re: Change Tohatsu 115hp to a 140hp?

All gone due to the EPA. 2005 was the last year for the carb two-strokes. Now they are DFI and cannot be gimmicked...At least on the cheap. We sold out back in May and could not get anymore...that really sucks.