bayliner performance

[gary111160]

Looking for advice again with my Bayliner. Just had 10 days on her for the first time after post purchase work etc. My question is this.

Boat is 2855 1997 with mercruiser 5.7 LX V8 and alpha one drive and a mercury marine high five stainless prop. All engine work carried out full service new headers and risers the works. Boat has clean bottom. I find th engine only revs under way to 4000 and whilst the speedo does'nt work the gps shows over ground a max of 22 knots one way and 26knts the other. I would have expected 30knts.

Does anyone have any experiance with this boat/engine to see if the performance is off the mark? and any feedback on fuel consumption or best cruising speed? Any feed back much appreciatted as always.

Gary

 

[jhr]

You should be getting 4,700 - 4,800 at wot with this engine. If everything's clean and serviced, the main suspects would seem to be either overloading (but you'd have to have an awful lot of gear and/or peeps on board to have this kind of effect) or the wrong kind of propellor - but I'm not an expert on this at all and, assuming it's the prop that was originally fitted, it should be correct.

Your estimate of 30 knots seems reasonable to me.

 

[redglow]

Have you tried trimming the drive out a few degrees at a time, this often helps to get the last few RPM out of the engine? Get her on the plane and then trim a few degrees, let it settle and then try a few more and let it settle again noting the RPM / GPS speed as you do. It won't take long to establish optimum setting.

Kev

 

[itsonlymoney]

Summat wrong there. The 2855 should be well up for 30+ and should get on the plane no prob. Sounds like wrong prop to me (only my oppinion of course)

 

[gary111160]

Thanks Guys, I'm not convinced its the original prop and I did'nt note the prop size when she was out thw water!!. I understand a new drive was fitted about a year ago. Not sure a five bladed prop would have been original.

I have played around with the leg trim and trim tabs and the speeds I mentioned seem to be the the highest and 4000 seems to be the max revs.

Gary

 

[davedpc]

Regarding the speed difference[not the revs] was there a tide giving you 2kts one way and minus 2 the other? Dave.

 

[gary111160]

As an approx. I would say yes about 2 knts. Thats why I did a run in both directions to get an average of about 24knts. Boat was not heavily loaded half fuel and water, two adults, usual kit.

 

[Alrob]

dont know if its any help but I have the 285 with 350 mag/b3 leg @ 4500 I get 37MPH

have a look on www.boattest.com to see if thay have a report on your model

I have never seen a 2855 with a s/s prop so would suspect its not the original setup also I thought pre 2001 2855 was fitted with the 7.4 L engine - probably wrong though

cheers

 

[gary111160]

Hi Alan.

Thanks for the link, I'll have a look. I am 100% on the engine fitted to my boat. All serial no's confirm.

Gary

 

[duncan]

high 5 won't be original - way too expensive!

has it been fitted /geared for wakeboarding? this would be my guess.

irst thing I would do is stick a standard recomended 3 blade prop on it and see what happens - it's such a common hull / engine that you should be able to get it within 2" pitch / 200 revs straight away and the props are very common so borrowing a second hand one from a mercruiser dealer with a view to purchase if it proves correct shoud be easy.

all the best

 

[gary111160]

Thanks Duncan. It does seem to be leaning towards the wrong prop. I'll take your advice and find the standard prop. and see what that does to her. Thanks again to you all for your input.

In the short time I've owned this boat the info/feedback on this forum has been fantastic.

Gary

 

[rowey2006]

hi
last time i was out in my maxum 2400 5.0l v8 petrol alpha one leg at full throttle i could not get over 4000rpm. i have std engine and std 3 blade prop tried trim up and down no difference.
same weight as you half fuel 2 adults etc..
we did have our canapy up and it was windy so that could have been my reason.
i had a thought going home from boat to try and rev engine out of gear to see if it will rev over 4000rpm if it will then prop is problem or my case canopy and wind.
i havent tried this yet as i have not been back to the boat
please let me know what you try and results.
regards
marc.

 

[spannerman]

Sorry but JHR is wrong I have here on my desk the 1997 Mercruiser specs book and the 5.7 LX with Alpha drive should pull 4200-4600 rpm (its the 350 Magnum that goes to 4800)
I have just come back from testing a 1994 version of the same boat with same engine and drive with a 3 blade ally prop and clean bottom and that pulled 4400rpm with a full tank and anchor winch on the swim platform so lots of weight in the rear. it did 28 knots on the GPS which equals 32 mph.
I ran a 2655 for 10 years on a 5.0 LX Alpha with a High Five 19" pitch prop and that pulled 4500rpm and 36 knots on a good day, the prop is fine for your boat but I suspect in the absence of mechanical problems etc the pitch is too high, I would imagine that boat would need a 17" pitch prop.
Best cruising will be at 3500- 3800rpm depending on loading, this will give best range, I fitted a fuel computer to mine and at that speed (allowing for your extra 20hp over mine) you will burn about 9 gph, full throttle will see the wrong side of 14gph again depends on load and conditions, I usually had two onboard and never more than 2/3 of a tank. The biggest effect on fuel consumption is the awning, I dumped the original and had a full length one made which transformed the boat and it was swept back at the same angle as the windscreen.