Prop Cavitation, Ventilation, or technique.... ?? Coming on plane from idle....

[LimaBravo]

Hey Club SeaRay!!

Here's another one from the new guy....

On my 370AC with twin 454's, as I come up on plane the port engine will occasionally rev to higher rpms than starboard....(feels like what I've read to be inboard cavitation?) I can quickly pull it back for a moment, about back to sync, then advance it again with starboard and we'll continue to plane and cruise fine. It seems to "catch up" when the throttle is pulled back and then advanced back in sync again.

So now, I don't go too aggressive with throttles on planing anymore and I can control it, but is this normal? I assume throttles need to be advanced slowly as an "immediate" throw from ide to full rpm's would induce cavitation / ventilation ??? It could just be my planing technique going too much throttle too quickly ?

Anyone have experience or opinion ? Based on previous heavy inboard gas boat discussions, I'm "pretty" sure it isn't mechanical, but don't know how to check those issues either.

Thanks for any input, please let me know your experiences or ideas.

 

[h_gerry]

Curious, are you using the engine synchronizer when this happens? If so, which model synchronizer do you have? My boat has the Sturdy brand synchronizer and when I advance the throttle the other engine will lag for a moment and then "over-rev" for another moment to catch up. If the engines will then synchronize eventually, it could be normal operation of the synchronizer.

If you are not using the synchronizer, then I suggest starting with some basics on the running gear: check the props for anything that would cause it to not be balanced (slightly bend blade; pitting; nicks on edge of blade; etc). Then look forward of the offending propeller and see if their is anything the could be causing turbulence that could interfere with the water flow to the prop.

You may also want to check the engine transmission to see if that could be slipping at speed and cause the over-rev issue. Check the fluid to make sure it is full, clean and does not have a burnt smell.

 

[LimaBravo]

Thanks for the info H_Gerry!! I'll be at the boat tomorrow and check the trans fluid.... everything else checked and no issue. NOT using the sync during the issue.

I really really appreciate the direction. I didn't think it could actually be slipping!