I have a 2011 Sundancer 340. Recently...

[nick1]

I have a 2011 Sundancer 340. Recently noticed that I was unable to advance the throttle speeds past 3200 rpm on either engine to get the boat up to plane. The boat ran perfectly if the rpms were below 3000, with no vibration or indication on any of the gauges that anything was amiss. Cause? 

[wingless]

What is the marine growth condition on the hull and on the running gear?

[nick1]

Shouldn't be any. The boat is maintained in exemplary fashion and stored indoors during the winter in a heated facility. Is waxed annually before being launched for the season.

[wingless]

Great!

The most common problem source is marine growth on the hull and on the running gear, especially at this time of year, when the water temperature is warmer.

[nick1]

Thanks wingless. A clarification on my initial post. If I shifted the throttle levers to max I was unable to get the rpms past 3200 ie half throttle 3200 rpms, full throttle rpms remained at 3200 with no change in boat speed.

[Capt_Dave]

That is generally caused from marine growth on bottom of boat. When it happen to me several yrs ago. I was in disbelief as well . My mechanic plugged into both engines said everything is fine when did I clean bottom last. I told him it was fine. He made me pull it out and said its not fine. He pressured washed it in about 30min I was back to 5000 rpms and on plane!

[SMT]

Agree with all. I live in FL and usually my driver cleans it every month. Went 6 weeks instead of 4 on the cleaning. Went out on 5th couldn't get full throttle had it cleaned took it out had full throttle again. Spoke with diver said this was warmer and worst growth he has ever seen in recent years.

[gtstang462002]

One more advocating to check the bottom/running gear. In the warmer months, if you are not running the boat at least every 2 weeks you are going to be needing the services of a diver. Weekly runs are more benificial to keeping everything clean in the warmer weather.

[doug5]

Don't rule out a tune up

[Sea_Ray_340_Swe]

Sounds like your not firing on all the plugs- change spark plugs/wires and tune up

[nick1]

It was the plugs. Two defective on one side, one on the other. Thanks for your help.