Hosrizon 6.2L Mercs V-drive / Normal RPM range

[wwhite]

Having some issues with fuel (10% ethanol mix) and wondered if what the normal rpm range is for this setup? 3200 rpm is abt 18 kts. First season with this boat (05 320 Sundancer) - mechanic is replacing fuel filters and plugs. Appreciate feedback.

 

[Hampton]

The only real RPM issue is the WOT (wide open throttle). There is a range for you engine. You need to tune your boat to achieve that range when boat bottom is clean (correct size of props, engines operating correctly...). I believe that range is 4800 - 5200 for your engines. Otherwise, the 320 w/ V-drives tends to require more RPM than most to stay up on a good plane. Generally, almost 4000 RPM is a decent cruise setting. A good rule of thumb is to not operate above 75 - 80% actual WOT for extended periods.

I don't use ethanol, and I keep my tanks full as much as practical to leave less room for cool, moist air to be drawn into the tanks everynight to deposit its water into my gas. Ethanol attracts moisture.