bscooter
New Member
- Aug 17, 2013
- 5
- Boat Info
- 28.55 bayliner sierra,comand bridge,full canvas,dinghy on davits mounted on custum swim grid,lowranc
- Engines
- 2009 mercruiser 496 with bravo 3
Hello to anyone that can help me with my puzzleing puzzle!!!!!! Here is the story and history...see if you can figure it out!!!!!! I bought a 2001 bayliner sierra 2858 with the command bridge.I immediately put in a brand new mercruiser 496 with a new bravo 3 (2009) It was installed by my local dealer.I followed break in instructions,then a few days later I took it out for a trip.After cruising for almost 2 hrs,i was surprised at how much fuel I was burning,and wondered if I was trimming it poorly.When I returned home I installed a fuel flow meter,turns out I had it trimmed perfectly.I was burning 80-85 ltrs/hr at 4700 rpm,doing 28-30 m/hr,depending on currents.Less than 27 m/hr and it starts to plane inefficiently.I had expected better economy,and my dealer/mechanic laughed at me.At approximately 65 hrs on the motor leg combo,i would be cruising along nicely,when suddenly the motor would just shut down.After a minute or so,it would start up and work fine....until the next time it happened.The time between incidents were not regular.I was later told by my mechanic that a bearing was seizing up and lo ading the motor up,causing it to shut down....drive it until something gives,it is warrantied.At 81hrs on the clock,it shut down again for the last time.The leg was making horrible grinding noises.Warranty gave me a new leg,i launched the boat,and took it for a 15 minute spin.I was delighted with the power and performance!! What a difference,and to top it off,i was only burning 50-55 ltrs/hr at the same settings that I normally cruise at!! YaHoo!!! ....So I thought....I told my mechanic the results,and he asked me if the top speed was the same,to check that the prop pitch was still a proper match for my gearing.I used the same props during all of this story. So I took it for another 15 minute spin...all is well,proper match,performance and consumption is great!! A few days later I load up,and head out for a trip. I am stunned and unhappy to see that I am burning 90 ltrs/hr. It is a bit rough out and we do have a load,but I am thinking that it shouldn`t make that much of a difference. 90 minutes later I stop to fish,and within moments an alarm goes off.The leg oil reservoir is low.I decide to go home,and keep it topped up on the way back.Turns out the prop shaft seal is leaking! It gets replaced,and into the water I put her again,but before I load it up to head out,i take it for a spin to see if I was burning a lot because of the weight.Nope,the best I could get her to run at was 78 ltrs/hr.This is now 2011,and my consumption remained at an average of 85 ltrs/hr. During the 2012 season,i started to notice a drop in performance,and I was also doing a lot of slow cruising at 1500 rpm,to save money,and extend the distance that I could travel on a tank of gas.I had a mercury tech come and look at the boat.He said that for a boat of my style,and weight,i should be burning between 50-60 ltrs/hr.I told him my story,and then he hooked up his computer,downloaded every second of the engines life,we went for a cruise,doing various speeds,ect.He did not see anything wrong,but sent the info off to be analized.The results said that there was nothing wrong with the motor. By the end of the 2012 season,i was making remarks about the poor performance.My mechanic was no help and didn`t really care.This year,2013,my first trip out,i did not try to get up on plane,and just cruised around casually.The second and final trip,i throttled up,and it took approximately 2 minutes to get on plane.I had to keep it at full throttle just to maintain 27 m/hr at 105-110 ltrs/hr.Usually I am at 1/2 throttle. I checked to make sure nothing was wrapped around the leg.My bottom paint is smooth and clean(new) the next 3 attempts at getting on plane were the same.The 4th time,she performed like usual...WIERD!!! What the??? The rest of that weekend it worked like usual.Then coming home Monday morning,i was cruising along at 4700 rpm,28 m/hr burning 90 ltrs/hr,18 minutes into the drive I heard a bang,the motor reved up,i throttled back thinking I hit something and spun the props.Reverse worked,forward doesn`t,and won`t go into forward any more.This leg has approximately 350 hrs on it and approximately only 50 of those are on plane.Tomorow the leg should be taken apart to determine what broke.But...why am I getting poor ecomomy,even after it did get good ecomomy,even if it was for 30 minutes.What would cause this? And why am I having leg issues? Any guesses? Thank you for any help that I can get. Proper maitainence is performed,oils ect.
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