tohatsu not firing

[squig]

hi all l,m new to site hop same one can help i have a 2006 tohatsu 18hp not firing on bottom cylinder got it off a mate so fare he changed carburettor for new one new coil new head gasket new thermostat checked compression 120 psi top cylinder 118 psi bottom cylinder new spark plugs checked timing new fuel line and tank it tyres to fire at about 1/2 to about 3/4 and same time it will pick up and go but if you back off to under about half throttle it will mis and stop firing on bottom cylinder tryed pulling plug wire off when idling top wire motor stops bottom wire makes no different to motor

 

[Sea Rider]

Welcome to Iboats,

Gee have spend lot of cash with no avail, that's the hardest and most expensive way to troubleshoot any motor. By coil, you mean the double Ignition Coil ? When carb fully opens up at which time advance mark does the timing plate stops righ in middle of both vertical mating surfaces ?

BTW, is it a 2 or 4 strokes motor ?

Happy Boating

 

[TOHATSU GURU]

You need to run the electrical tests on the ignition components. Those procedures and specs can be found in the service manual. Once you have eliminated the ignition system you can start in on the fuel system and eliminate the possibilities by trial and error.

 

[squig]

2 stroke checked timing 25 degrees full throttle 3 degrees no throttle changed coil one with spark plug leads he was told it was faulty by mechanic he checked cdi unit and coil under flywheel and was told they where good witch way the arrow run on the pipe with the value in it can not find it in repair Manuel

 

[squig]

update toke boat to mechanic he can fix it

 

[Sea Rider]

Just for the record, report what was wrong with it.

Happy Boating

 

[squig]

mechanic found new carburetor was blocked he had to use air and wire to unblock same think was in there from factory he also give it a tune up haven't toke it out will take out tomorrow to see how it goes

 

[Sea Rider]

Good to read that carb was found faulty, which type of boat will be powering that nice OB and how loaded do you intend to use it ?

Happy Boating

 

[squig]

carburettor was fault but still the same back at machines try again will keep updated

 

[km1125]

Does the carb feed the two cylinders differently on the two strokes?? I would think that if it was a carb issue it wouldn't be just the bottom cylinder missing.

 

[pvanv]

A NEW carb was fouled? Doubt it.

 

[squig]

update drive shaft bent gearbox started leaking bottom seal in motor leaking sucking air in got rid of motor .i can buy a 2018 hidea 15hp it looks the same as my mates yamaha theres no different his cowling fits straight on it what do you people think of them motors ive been told they are the same

 

[Sea Rider]

Your tech issue as described is very confusing.

Do you mean the lower powerhead round big seal was found faulty ? If so will need to replace an oil seal and a ring oil seal located at lowwer extreme of crank shaft along a new base gasket. All 3 just costs $ 32.00 + $ 8.00 shipping. For 40 bucks wouldn't want to spend way more going for a PRCH outboard.

The Tohatsu 18 HP it's one of its kind, has 300 CC compared to just 250 CC of any other 15 HP outboard brand. The issue with PRCH clone outboards are the light materiasl used that doesn't last that long compared to Jap ones and spare parts availability.

Happy Boating