Nissan/Tohatsu 25/30 HP 2-Stroke Timing

[drgmaps]

I have a 25hp 2005 Nissan 25C3 that I am converting to a 30hp 30A4. I changed out the carburetor/manifold gasket from the restricted 25C3 to the unrestricted 30A4 gasket. She fires right up and runs like normal (haven't taken her out on the water yet though, just muffs).

Next step is to adjust the timing. This is where I need help. The factory timing for the 25C3 is 20￮ BTDC and 2￮ ATDC. Picture 1 shows the factory timing at WOT and picture 2 shows the timing with the throttle closed. I have marked in picture 1 what I think is the 20￮ mark. If I am correct then the 25￮ mark is one mark to the left. Please confirm. One thing I noticed is that the advancer arm does not touch the open or closed stopper bolts (see red circle in pictures) like my Clymer manual say they should. Do I need to fix this when I adjust the timing so that they touch?

To adjust the timing to the 30A4 standard (25￮ BTDC and 2￮ ATDC) do I just need to shorten the timing link till the 25￮ mark aligns with the mating line of the crankcase? Won't this then change the closed throttle timing position? How do I fix that?

Thanks.

 

[savage]

Re: Nissan/Tohatsu 25/30 HP 2-Stroke Timing

I'm not 100% sure but I think you have to put the motor in forward gear in order to get WOT. The bracket should then hit the WOT stop bolt and you can check max timing.

 

[TOHATSU GURU]

Re: Nissan/Tohatsu 25/30 HP 2-Stroke Timing

As incorrect adjustment can cause you to blow the engine up and think it would be in your best interest to take it to a mechanic.

 

[drgmaps]

Re: Nissan/Tohatsu 25/30 HP 2-Stroke Timing

As incorrect adjustment can cause you to blow the engine up and think it would be in your best interest to take it to a mechanic.

What's the average cost to adjust the timing on an engine like mine?

 

[TOHATSU GURU]

Re: Nissan/Tohatsu 25/30 HP 2-Stroke Timing

It takes two minutes...Whatever your local dealer has as a minimum shop charge.