Speed Problem

[Phil C]

I recently purchased a 1999 SEA RAY 420 Aft Cabin with two Caterpillar 340 h.p. diesel engines with less than 230 hours on them. My top speed only reaches 12 knots. RPM and sound on each of the engines appears normal and the engines are in sync and the boat is trimmed out. However, it runs like there's a governor on the engines. Anyone else experience this type of problem.:huh:

 

[Paulkarlsven]

I recently purchased a 1999 SEA RAY 420 Aft Cabin with two Caterpillar 340 h.p. diesel engines with less than 230 hours on them. My top speed only reaches 12 knots. RPM and sound on each of the engines appears normal and the engines are in sync and the boat is trimmed out. However, it runs like there's a governor on the engines. Anyone else experience this type of problem.:huh:

What is the bottom like is it clean? When was the boat hauled out last and pressure washed?

 

[twyant]

What is RPM at WOT should be 2850 Rpm Have The same boat I run 22-24 mph at 2400 rpm 29-30 mph WOT 2850 depending on load seas and water depth.
Very nice boat we love it lots of room and love the cats 1900 hrs no problems if I can be of any help just ask

 

[ktcanuck]

I just bought a 1996 420AC with 420 Cat 3126. On the survey we got 2800 RPM (measured) and 24.2 knots (GPS). Bottom was clean but is in need of rework.

 

[rmadaris]

My props needed reworking. Got me back to 2680 (WOT) rpm and 33-34 mph. Have u had them checked out?