Nissan 25hp or 30hp

[farmboy8410]

hi all i recently bought a carolina skiff with a Nissan 30hp atleast thats what the cowling says. i saw the boat the day it was bought by my friend it had the same 30hp cowl on it. The model # is ns25c3 serial # 62629 so is it a 25 or 30 and does any body know what year it would be ... thanks jeremy

 

[Sea Rider]

Re: Nissan 25hp or 30hp

The only way to know if it's a rebadged cowling to 30 HP, is to remove carb and if you find a plastic gasket air restrictor between carb and engine body is a 25 HP. 30 doesn't have an air restrictor, just a plain open gasket in middle.

Happy Boating

 

[farmboy8410]

Re: Nissan 25hp or 30hp

Thanks, are these motors reliable, any problems i should know about. thanks again Jeremy

 

[Sea Rider]

Re: Nissan 25hp or 30hp

Thanks, are these motors reliable, any problems i should know about. thanks again Jeremy

Nice engines, well tuned performs excellent.

Happy Boating

 

[farmboy8410]

Re: Nissan 25hp or 30hp

If it does have the restictor can i take it out and now its a 30hp if so will that require major carb adjustment thanks..

 

[Sea Rider]

Re: Nissan 25hp or 30hp

Partially, must get a new 30 HP gasket (code 346-02011-0) and check advance timming if reaches 25? at wot. Probably 25 has restricted full throttle to 20? too, if so, readjust to 25?. Start buying part at any Tohatsu dealer/service.

Happy Boating

 

[TOHATSU GURU]

Re: Nissan 25hp or 30hp

If it does have the restictor can i take it out and now its a 30hp if so will that require major carb adjustment thanks..

Yes, you could remove the gasket and no it wouldn't require any major carb adjustments.

 

[Sea Rider]

Nissan 25Hp to 30 Hp

Nissan 25Hp to 30 Hp

After replacing the old 25 gasket for the new 30 HP carb gasket, perform this simple test to see if your engine will require a + 5? timming advance or not.

1-Remove cowl, place gear in forward.

2-Move throtle to fullest position, check, if white roller stops at middle cam (inside depression) you have 20? timming, if roller stops at fullest left cam you have a 25? timming, check pics. If having 20? advance to 25? by means of A stopper.

3-Loose securing nut, turn screw CCW some milimeters away, throttle fully again, you will see timming mark travelling to 25?, when reaching this position, tight nut against screw. Final check: retain carb pawl with finger to wot position, throttle tiller vigorously back and forth to wot, should hear a slight hammering sound when cam bangs against white roller, re adjust stopper A so to achieve this final position.

4-The extra 5 HP is found at full wot.

Happy Boating

 

[Commando C2]

Re: Nissan 25hp or 30hp

hi
i have one of these engines and had a problem with the wiring loom where it comes out of the magneto/flywheel.
There is a clip that holds the loom and as you accelerate the loom moves to advance the ignition, over time the clip had cut through the loom and the engine died at sea.

took me a while to notice it but rejoined the wires and it worked.
i did have an ht lead go on me so replaced them both.

Its worth replacing the plugs and leads so you know they are good from the start.

i found mine takes a while to pull the fuel through if you run the carb out between uses so now i tend to leave it in there and it starts first pull.

 

[farmboy8410]

Re: Nissan 25hp or 30hp

Thanks everybody for the help. The timing is at 25 degrees but i still have the 25hp gasket. Does making this engine a 30hp cause any premature wear. thanks jeremy