tohatsu 15 hp, revs up and down

[davidsg1a]

Good evening folks I have bought a tohatsu 15 hp four stroke, it's only ran for 5 hours and hasn't been used for a year, took for a run and wen I put it in gear it revs up and down, I'm using clean fuel and oil level is fine, could anyone here help. David

 

[Sea Rider]

Welcome to Iboats,

How new/old is that engine ? When revving up/down does the speed increases/decreases accordingly ? Is carb, tank, fuel pump, fuel lines in immaculate clean state cond ?

Happy Boating

 

[davidsg1a]

The engine is 2012 and only had five hours run time, everything is in great condition, I'm very surprised I'm having a problem, the guy I bought it off took great care, when turn the revs up it goes for a few seconds then slows down then speeds up again.

 

[davidsg1a]

The engine is 2012 and only had five hours run time, everything is in great condition, I'm very surprised I'm having a problem, the guy I bought it off took great care, when turn the revs up it goes for a few seconds then slows down then speeds up again.

 

[Sea Rider]

Slows down, speeds up while maintaining a constat throttle setting ? Let's say 3/4 throttle...

Happy Boating

 

[davidsg1a]

Yes that's what's happening.

 

[Sea Rider]

Could be anything, inclined to a fuel related issue, probably a fuel restriction somewhere betweeen tank and carb, check ..

Happy Boating

 

[davidsg1a]

I thought at first fuel problem, i check all thé lines and all seems ok.

 

[TOHATSU GURU]

Have your carburetor cleaned.

 

[HaMm3r]

You are remembering to open the vent on your fuel tank (assuming it has one), right?