Speedster fuel additive?

[Chulok371]

Trying to sell my boat and went on sea trial and boat started fine but ran bad. Motor sounded strong like it wanted to go. Boat was sputtering and would on hit like 26-29 mph. Should I drop joule and put new fuel back or should I just put a fuel additive .I have about half a tank of gas maybe a little more . I'm also going to change spark plugs at same time so I'm not going back and fourth

Thanks

 

[speedster32940]

Sounds like the problem I had. Spark plug change fixed it without fuel additives.

 

[LouDoo]

If the fuel has gone bad, more than 6 months old, it's too late for an additive, try new spark plug, but you may need to drain the tank and add fresh fuel.

Lou

 

[cheappc]

Wow doesn't that sound like wear ring and cavitation "sounded like it was fine but didn't go fast only 29mph"?

 

[pete63]

how is it running out of the water? is it going up and down the rpm range ok?