tohatsu 30 hp engine dies at low speed

[blue boats]

have a tohatsu that dies at low speed. starts ok. idles ok. runs at full throttle fine. but when brought back to trolling speed it dies. changed spark plugs, coil, cd, carburetor, fuel pump, checked fuel filter and thermostat. no change. engine is a two years old with about 200 hrs on it. so pretty much new. i have 6 other engines identical that do not have this issue. any help would be great.

 

[TOHATSU GURU]

Re: tohatsu 30 hp engine dies at low speed

Why don't you take it into an authorized dealer as it would be under warranty if it is only two years old? Also, why change out everything that you have without diagnosing the problem? Basically you have thrown money at a dart board so far...If you really want to do this yourself, pull out the factory service manual and begin running the tests contained within. It's a process of elimination, but at least you will not be buying any parts until you determine exactly what is wrong.

 

[Sea Rider]

Re: tohatsu 30 hp engine dies at low speed

Idle speed seems very low, with warm engine and at neutral adjust carb screw CW a bit, so that when gearing forward the engine doesn't die, adjust untill you achieve this working condition. When at neutral at idle speed, does engine dies too ?

Happy Boating

 

[blue boats]

Re: tohatsu 30 hp engine dies at low speed

tried messing with the mixture screw for about two hours. sometimes it seemed great , but minute later it would change. it was hard to start. almost like there was water in the cylinder, kinda hard to pull, then easy to pull. i have 6 of these so its easy changing parts from one to another. also down here there is no service center and warranty is only one year. i have alot of experience with engines. i have no problem tearing it down further. just was hoping someone has had this problem before and could lead me to a simpler solution. thanks for you help.

 

[Sea Rider]

Re: tohatsu 30 hp engine dies at low speed

Those are 2 or 4 strokes engines ? You shouldn't mess with mixture screw, is factory delivered working very well, probably have a carb issue, if it's a 2 strokes probably not well cleaned, soak it in real dip clean formula and place mix screw same as in other workin well engines. Usually 11 mm from screw base to upper head measured with rear side of caliper.

Happy Boating

 

[TOHATSU GURU]

Re: tohatsu 30 hp engine dies at low speed

Look at the fuel system in it's entirety. Then check for carb spitting.

 

[blue boats]

Re: tohatsu 30 hp engine dies at low speed

went through everything again. checked spark plugs after engine run. upper normal. lower whitish. head gasket?

 

[TOHATSU GURU]

Re: tohatsu 30 hp engine dies at low speed

Could be. Time to pull the cylinder head.