18 HP Tohatsu idles bad when cold

jmill15

Recruit
Joined
Jan 23, 2006
Messages
3
My 18hp tohatsu motor doesn't idle very well when it is cold. It will shut off 7 or 8 times before it ever warms up and runs smooth. The choke will not even keep it running. I think it could be in the fuel filter or something but i am not much on boat motors. Any help would be greatly appreciated. Thanks
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: 18 HP Tohatsu idles bad when cold

Clean the carb and then reset the adjustments.
 

jmill15

Recruit
Joined
Jan 23, 2006
Messages
3
Re: 18 HP Tohatsu idles bad when cold

Not sure i understand what tstat is. Please verify that for me. Thanks
 

TGuy

Petty Officer 1st Class
Joined
Mar 17, 2005
Messages
217
Re: 18 HP Tohatsu idles bad when cold

tstat=thermostat
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: 18 HP Tohatsu idles bad when cold

I would focus on fuel system, too rich, too lean. I would expect a stuck open thermostat would also cause too cold running conditions, ie it would never warm-up. A thorough carb cleaning and readjustment would be the first job to tackle.
 

ericab

Cadet
Joined
May 19, 2008
Messages
6
Re: 18 HP Tohatsu idles bad when cold

I purchased a new 18hp Nissan (Same Thing) last year. By the end of the summer it would not idle, but would run once heated up. Took it to the dealer and they dianosed it as the Bi-Starter. The Bi-Starter is the small capsule looking devise with a couple of wires coming from it. It essentially perfoms the same function as a choke. It allows the engine to idle when cold.

Hope this helps. I had purchased the maintenance manual, and the Bi-Starter is not discussed.

I have had my new engine out twice this season and on the second trip after stopping for lunch the engine now will only run at idle speed......go figure

Very unhappy with this engine.........

diver1@concast.net
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: 18 HP Tohatsu idles bad when cold

Clean the carburetor. After a year of use you probably have a dirty carb. From now on run the gas out of the engine after every use and only use fuel less than 2 months old.
 
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