Nissan 25hp Unable to locate serial number/model #/year

jaygees · May 3, 2011

I recently purchased a 25 hp Nissan motor. The man I bought it from got it on trade for some work a year or so ago and has no info on the motor. The serial number plate is missing from the outside of the motor.I found 2WT 680 on the side of the head, and 1THH003 on the lower block. Are either of these a good serial number? I was unable to locate any plugs on the block. I am trying to find what year/model this motor is. Any help is appriciated.

Thanks,
John

pvanv · May 4, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

John,

If you have a 3-cylinder motor, it's a 4-stroke. Further, if it has 3 carbs, it's an NSF25A; If injected, 25B.

If you have a 2-cylinder motor with one carb, it's a 2-stroke, possibly a 25C2 or 25C3. If so... is it blue or grey? Are the spark plugs threaded in from the port side or starboard side?

Year is unimportant for servicing Tohatsu/Nissan OB's, but model (and for some situations, serial) is very important.

jaygees · May 4, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

Paul,
The motor is a 2-cylinder 2-stroke blue motor with grey cowling. The spark plugs thread from the starboard side. I am unable to locate a plug showing the serial number. The only numbers i have found are 2WT 680 on the head and 1THH003 on the lower block. Not sure if im missing the serial number somewhere on the block?? I want to make sure when i need to order parts i am getting the correct ones. Thanks for your assistance.
John

TOHATSU GURU · May 4, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

It could be a 25 A,B or C series.

jaygees · May 5, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

The motor is a 2-cylinder 2-stroke blue motor with grey cowling. The spark plugs thread from the starboard side. It is not injected. I am unable to locate a plug showing the serial number. The only numbers i have found are 2WT 680 on the head and 1THH003 on the lower block. Not sure if im missing the serial number somewhere on the block?? I want to make sure when i need to order parts i am getting the correct ones. Thanks for your assistance.
John

TOHATSU GURU · May 5, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

It's a 92 or older, A, B or C.

warrenhemby · Nov 5, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

im having the same problem. i have a 1998 25 hp nissan short shaft 2 stroke. South carolina DNR requires a pencil trace of the serial number. Any idea where its located. thanks in advance

pvanv · Nov 5, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

Would be on the tag on the transom clamp. Also lists model. And cannot be pencil-traced, as it is printed, not stamped. Failing that, the serial will be on a the block. Typically on a soft plug.

warrenhemby · Nov 6, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

thanks paul i only found the numbers jaygees found. i look again thanks again

warrenhemby · Nov 6, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

well......no luck finding a serial number on a soft plug..on the left rear(as you stand looking for the rear of motor) right above the exhaust cover there is 5 digits stamped. if this is it what goes in front of it. i cant believe thats all the serial number. nice lady at dnr....no serial number no registration..kinda like "no ticket no laundry"

pvanv · Nov 7, 2011

Re: Nissan 25hp Unable to locate serial number/model #/year

Yes, you have it. 5 numeric digits in the serial number. Complete description is NS25 (then an A, B or C, depending on what revision you have... no way for us to tell), then the serial. You can contact http://www.nissanmarine.com/contact.html to see if they can correlate the serial to a specific model revision and/or year of manufacture.

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