2002 Searay 340 w/T8.1 Horizon questions

[osd9]

Here'a a pic from my 2002 380DA.....it had a late 2001 build date....

 

[Pseudomind]

Here'a a pic from my 2002 380DA.....it had a late 2001 build date....

The only difference I see is the riser added on top of the manifold, from what I can tell my bilge looks the same as yours did when you had the 380, to include the Auto Pilot hydraulics on the transom. My slip neighbor has a 2001 and his is located else where. His Halon system is on the transom

 

[Larry]

Thank you all for great answers about these 7.4L MPI Horizons (380) and great lessons.

Larry, you indicated that you have a 3rd set of engines in your boat, may I ask why you have gone through many sets of engines in relative short time ?

What's kind of propellers do you have and what is your recommendation in term of tweeking to make them perform better on the 340 ?

Thanks

Andy

Andy,

The reason my boat had 3 sets of engines (all between 2000 - 2001) was due to the known Merc water intrusion issue with the old stlye exhaust (log style), the log style did not seem to cause any issues with the standerd 310hp engines. The issues with the Horizons was there valve overlap timing which would cause a vacum when you shut the engines down, and when this would happen the engine would suck the remaining water that was in the exhaust tube back into the engine (not a good thing!!). This problem was corrected when they engineered the lift type mufflers (pot style), I would think that by now all boats that had these Horizon motors have been retro fitted with the new exhaust system. My boat had all the documentation from the previous owner supporting the changes, when I boat my Sea Ray I called Merc and gave them the engine numbers to check for any outstanding campaigns, they confirmed the history on my boat and even told me that Merc spent about $40K in R&D on my boat and that mine was the test boat for the new exhaust system...

As far as the prop tweeking, I can't tell you what will work on your boat (your boat is a little different as far as weight ond not sure of your gear ratio), but find yourself a good prop shop that uses Prop Scan or one of the other computer aided systems and this my take some trial and errors to find your "sweet spot"...