Tohatsu 2T 120HP carb. (M120A2) and bioethanol

[Xabi]

Hi.

we are a diver team, owner of a Valiant DR600 and an 120 HP carb. of 1999.
Located in the center of France, far from any efficient Tohatsu dealer (and the ones contacted by phone are not aware of engine maintenance), I've few question to ask to the community

As the unleaded is quite expensive here (> 6$ per gal.) and the ethanol E85 quite economic (arround 2$), cruising at full load, it may be interesting to change.

Do you have any feedback on carburation with bioethanol ? Efficiency, mechanic issues, corrosive activity, maintenance...

As the former owner was a mechanic expert, and the motor very punchy, I don't know if it was modified from 120 to 140 HP.
- Is there any impact if we migrate from unleaded 95 to E85 (octane indices from 95 to 102) ?
- Is it possible to check if the motor is in "normal" state or tuned ?

Thanks for any kind of help you are able to provide
KR
Xabi

 

[pvanv]

Your motor will run on any (E10 or less), 87 or higher octane, unleaded gasoline; 89 and above is preferred. Extra octane won't affect or improve running, but some premium fuels have better additive packages, with better/more detergents, so they are fine. All those fuels are unleaded, but some may have some ethanol added. Up to 10% ethanol will work OK, with a slight loss of power, but you must religiously empty the carbs at the end of every day (either by idling until stalling or by opening the drains), unless you will be running again the following day, because the ethanol attracts corrosive water, which can pool in the carb, and in fact, the ethanol itself is a bit corrosive, since it is sure to have some dissolved water in it already. It is also hard on plastic and rubber parts of the fuel system, including fuel pump diaphragms and "rubber" fuel lines.

DO NOT RUN E85, which is 85% ethanol. It will run poorly, give poor fuel economy, burn too cold, have trouble mixing with the TCW3 oil, and is a real problem for all carbureted outboards of all brands and all vintages. Again, DO NOT EVER RUN E85.

NEVER RUN E85.
NEVER RUN METHANOL.

If the WOT limiting tang on the carb assembly has been bent away to allow complete opening of the throttle butterfly, and the timing is adjusted accordingly, you are running as a 140; otherwise, you are running as a 120.

 

[Sea Rider]

Tohatsu factory recommends MAX 10% Ethanol use, E85 is for modern car use, provided that has been modified to run such high octanes. Brasil uses high octane E fuels on carbed OB's, with disastrous results.

If OB is in excellent shape, can better performance with a prop maximization, for that will need a tach..

Happy Boating

 

[TOHATSU GURU]

It will also end up drying out the cylinder walls resulting in scoring.

 

[Xabi]

OK...
Then, I will forget this option, except for a Crash test (I will provide the results if it ever happens).
But not today.

Thanks.

 

[Sea Rider]

The only alternative is to use non E or max E10 fuels at a much higher cost. Anyway, who said boating was a cheap sport. LOL!!

Happy Boating

 

[Xabi]

yes.....
never cheap

but if I could buy a 12" map/sonar/computer instead of burning som fuel