40Hp EFI Surging at all speeds except idle

[cbaker425]

Engine surges at most speeds except idle and wide open throttle. This is a 2010 model. Has always run like a top since new till recently. Last year would occasionally smoke on start up. The plugs were replaced last year and I checked the water separator and filter. Fuel in tank is new. Any ideas would be appreciated.

 

[pvanv]

What do the plugs look like now? Have you reset the TPS? What is the amp-hour rating of your battery, and how old is it?

 

[cbaker425]

Plugs look good, Battery replaced at the start of last season. Not sure how to reset the TPS. Thanks for the suggestions to check. This afternoon worked fine until on the way home. After running at 3/4 throttle for about 5 minutes it started to slow down then started to surge up and down till I went wide open the rest of the way home. Will try to do a load test on the battery tomorrow.

 

[Dwightmarlene]

I have a 2004 90 hp Nissan that surges when operating between 1800 and 2200 rpm. It also occasionally stalls when going into gear. Did you find a solution? Any suggestions would be greatly appreciated!

 

[Sea Rider]

It also occasionally stalls when going into gear.

Probably your idle speed is too low, with engine warm adjust idle rpm to a point engine doesn't die when going into gear, adjust as needed.

Happy Boating