Partner Sites:  www.BOEmarine.com | www.CBangler.com | www.BandofBoaters.com

Page 1 of 3 123 LastLast
Results 1 to 10 of 22
  1. #1
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Unhappy What's wrong with my 8.1 Horizon Engine?

    Splashed the boat today. I was looking forward to having both engines operate at the same WOT now that the props have been redone, but...

    The stb engine still lags behind the port engine (like last year). Both are the same until around 2000 rpm, then to keep the engines sync'd more throttle must be applied to stb. My normal cruise speed is 3500 rpm and at that speed, both engines seem to operate well enough. It's just that the stb engine must have about 10-15% more throttle to maintain sync. It was also using more fuel last year than the port engine.

    It gets more evident past this point that there is an obvious issue. If I try to increase both to 4000 rpm, the stb throttles must be to the wall, while the port throttles still have plenty of room. (I didn't run this way long for fear of causing damage to something ) After reducing speed with both engines to 3500 rpm, I tried increasing the speed first on the stb without altering the port. I could hear and feel a shutter as I applied throttle. The same test was done with the port engine, it simply gunned ahead and the boat began to be steered by the increased thrust on the port prop.

    Before docking I tested it off plane, at idle with both engines in gear. Spinning the boat port or stb by using each engine allowed me to hear and feel more distinctly that the stb engine is not smooth running and powerful like the port engine. Once throttle is applied, the shake and paa-paa-paa sound is evident. Other than this, the engine starts well, runs well (at lower rpms), and doesn't use oil.

    I've got my plan of action to try and diagnose, but wanted to get those smarter/more experienced (or both) to provide some advice first.

    FYI - I purchased the boat late summer 2008 and have not really taken it on any long trips. I don't know what has or has not been replaced on the boat other than the things I've done since ownership. The issue was noticed last year, but I decided to have the props balanced first to rule out that as an issue (which was a good thing since the props were badly pitted from electrolysis and they were out of balance).

    Please - Bring on the wisdom.
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  2. #2
    Join Date
    Apr 2009
    Location
    long island
    Boat
    sea ray
    Details
    370da
    Engine(s)
    7.4's
    Posts
    218

    Re: What's wrong with my 8.1 Horizon Engine?

    I would start with the basics. Compression test first. Inspect the spark plugs. They should all be clean and show an even burn. If all is correct start looking at ignition and fuel supply. ? could you have water in one tank ? Also check fuel pump pressure. Keep us informed as to what you find please

    1998 370da 7.4 mpi
    Long Island N.Y.

  3. #3
    Join Date
    Nov 2006
    Location
    Panama City, Fl
    Boat
    Sea Ray
    Details
    2008 44 Sedan Bridge
    Engine(s)
    Cummins QSC-500's Straight Drives
    Posts
    7,601

    Re: What's wrong with my 8.1 Horizon Engine?

    Yep - Air, Spark, Fuel.
    John

    2008 44 Sedan Bridge - Shell's Island II - Our awesome 44!
    2005 340 Sundancer - Shell's Island - The perfect 340! - TRADED!
    1997 250 Sundancer - Hampton's Inn - SOLD!

  4. #4
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Re: What's wrong with my 8.1 Horizon Engine?

    Regarding fuel... Would a spin on fuel filter/water separator get clogged enough to affect the engine in this way, and if so, would the affect not worsen over 30 hrs of use?

    By the way, my engines do not have any other filter (like an in-line or cool fuel filter).
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  5. #5
    Join Date
    Aug 2008
    Location
    Madison, MS
    Boat
    Sea Ray
    Details
    2001 380 DA
    Engine(s)
    T8.1 Horizons
    Posts
    1,253

    Re: What's wrong with my 8.1 Horizon Engine?

    Had the same problem last year....change the plugs.
    Southpaw II
    2001 380 DA
    Madison, MS

  6. #6
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Re: What's wrong with my 8.1 Horizon Engine?

    Plug inspection/replacement was second on my list. First was checking out the engine in the dark while running to see if there is a light show anywhere. To best reveal arcing should the engine be under load or just at a fast idle like 2000 rpm??

    From your description of fuel starvation, that's probably not it - but I'll be changing the filters anyway (but it's way down the list)).
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  7. #7
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Re: What's wrong with my 8.1 Horizon Engine?

    Quote Originally Posted by sfergson727 View Post
    http://cgi.ebay.com/ebaymotors/AC-De...item45f0728b82

    I bought 16 plugs from this guy for $47.60 shipped. They are new.

    WOW - that looks like the lowest price we'll likely ever see. I'm going to order my 16 as well. Thanks!

    What did you put in as an "offer" to get that deal?
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  8. #8
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Re: What's wrong with my 8.1 Horizon Engine?

    Well, I've submitted the same offer and will report back when I know.

    Thanks for the tip (no "platinum pun" intended )!

    I hope it's as simple as new plugs. It wouldn't surprise me if the plugs were the OEM's (boat now has 380hrs).
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  9. #9
    Join Date
    Dec 2008
    Location
    Sarnia, Ontario, Canada
    Boat
    Sea Ray
    Details
    340 Amberjack
    Engine(s)
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Posts
    1,738

    Re: What's wrong with my 8.1 Horizon Engine?

    Deal Accepted! $45.60 plus $2 shipping for 16 plugs!!

    The vendor says "Sea Rays Rock - I'll sell to anyone on your forum for this price, just have them mention Sea Ray!" He's shipping Monday.

    Thanks again.

    I'll be checking for a light show tomorrow (possible bad wires) and keep everyone posted as to what I discover. Plugs should be here next week too.
    Posted by Jim of "Island Rhythm"
    2001 Sea Ray 340 Amberjack
    LOA 38', approx 18,000 lbs & 13.5' Beam
    Straight Shaft Drives


  10. #10
    Join Date
    Mar 2008
    Location
    Lake Chickamauga/Marietta, GA/Ft. Myers, FL
    Boat
    Sea Ray
    Details
    2006 Sea Ray 58 DB
    Engine(s)
    MAN CRM V8-900s, Twin Disc Drives; Onan 21.5 Generator
    Posts
    2,732

    Re: What's wrong with my 8.1 Horizon Engine?

    Jimmy,

    I see you have 380 hours - thanks for posting that. I think everyone is right on about the plugs - also, if your 8.1s have the inline fuel filter (you'll see the one for the stbd engine on the inboard side of the inboard stringer and the port one is on the outboard side of the port engine's outboard stringer) change those too - in addition to changing your water separator spin on filter.

    My dockmate's 340 wouldn't run above 2600 RPMs and those items fixed it.

    After you do that, give your fuel tanks a full dose of Marine Stabil and I add Chemtool B12 as an injector cleaner...

    Carter and Susan Chapman - "Reward" - Cape Coral, FL/Lake Chickamauga, TN
    2006 Yamaha VX110 Deluxe "Blue Lightning"
    2013 Nautilus AB Tender/40HP Evinrude "The Silver Hornet"
    2003 Sea Ray 410 Sundancer "One Sweet Day" (Sold - I REALLY miss her -another great boat)
    2005 Sea Ray 340 Sundancer "Reward" 8.1S V Drives (Sold - I Miss her - Great Boat)
    Avatar is "Sunrise Over the Bering Sea" at 35,000'

Similar Threads

  1. Did this damage engine? Pluq wires wrong, backfiring
    By andyr in forum Gas Engines/Drives/Transmissions/Props
    Replies: 7
    Last Post: 10-14-2010, 08:23 PM
  2. Horizon Engine 7.4 gen VI oil in cooling system head will not come off
    By jkmoore in forum Gas Engines/Drives/Transmissions/Props
    Replies: 6
    Last Post: 08-13-2009, 09:34 AM
  3. Horizon Engine 7.4 gen VI oil in cooling system head will not come off
    By jkmoore in forum Ask a Sea Ray Employee...(No Longer Active)
    Replies: 0
    Last Post: 08-12-2009, 06:51 AM
  4. Whats wrong with the diesel engine forum?
    By SCORPIO in forum General Discussion
    Replies: 22
    Last Post: 04-07-2009, 07:50 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •