Nissan 8hp tuned up to 9.8?

[DennisRB]

Is the Nissan 8hp just the same motor as the Tohatsu 8 and 9.8?

If so does this mean it is a tuned down 9.8? Respectively does that mean it can easily be tuned up to 9.8? What would be needed?

[Chuck Losness]

If you are asking about a 4 stroke, I can't help you.
I have a Nissan 8hp 2 stroke. The Nissan 8hp 2 stroke is made by Tohatsu and is the same as the Tohatsu 8hp . The 9.8hp is the same basic engine with 3 changes as I recall. The jetting in the carb is different, the cylinder head is different and the exhaust plate on the side of the engine is different. I have not made any changes to my engine. A friend of mine changed the jets in the carb in his 8hp to the 9.8 jets and thought the change made a difference. He is now able to get up on plane in his dinghy faster and easier than before the change.

[DennisRB]

Thanks its the 2 stroke. I have been searching and some sites say all you need to do is change the carb as it is bigger (jets alone will only adjust the mixture and not allow more airflow). I did not know the head and exhaust plate is different.