Tohatsu 18 hp 2 st seems to be overadvanced. How do I adjust the timing.

[TQA]

Re: Tohatsu 18 hp 2 st seems to be overadvanced. How do I adjust the timing.

Thank you sea rider I will go and check this adjustment and report back.

 

[TQA]

Re: Tohatsu 18 hp 2 st seems to be overadvanced. How do I adjust the timing.

If anything mine is a little tighter than you describe. This would mean that the carb is fully open a little sooner than if I still have free movement of the little roller at WOT.

If I were to slacken off the rod this would mean that the advance would increase by a little. My problem is that I want to achieve the reverse and retard the ignition slightly to stop the detonation occurring

 

[Sea Rider]

Re: Tohatsu 18 hp 2 st seems to be overadvanced. How do I adjust the timing.

TQA,

You have not said anything about you magneto timing measurement. Is it between 28.0/28.3 mm as seen on previous posted pic ? If not you need to adjust this issue first before checking/adjusting carb sync. Check. By moving carb sync you are in no way moving magneto timing as this adjustment is completely independent from carb. You are retarding a bit carb from opening full before roller hits high hill cam.

Had same issue on my last 18L, came factory delivered with flaws, didn't put engine into operation as was delivered, carb syc was corrected before testing, now that horse it's runing wild at 5,780 from it's max 5800 factory stated rpm.

Lower plug tends to foul/wet much faster than upper one, this is normal, but not an issue for plugs to be changed once a month. Check your fuel/oil ratio is 50:1. If still having detonation issues after carb sync, you could have a ignition coil failure due to overheating, shorting, producing poor spark at higher rpm, causing detonations, plug to foul, short on just one side. Buy a new ignition coil and test.

Happy Boating