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Old 01-06-2015, 07:29 PM   #1
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Help Unlocking some speed?

I have just bought an 21ft bernico believed to be a late 90's hull with a 2008 300xs with a 1.62 sport master fitted with a 24 inch trophy plus

Last week was the first time I got to drive the boat on a flat sea and got to have a play I am very pleased with the boat and love to drive it but I am abit disappointed with the top speed I can't get it over 61mph on the gps at about 5100 rpm I have slowly trimmed it up to the point where I can't turn the steering and have a huge rooster tail just to see what's happening but no gain in speed just more revs and noise as expected when over trimmed lol

This was with no water in the tank and the tabs all the way up

Also I notice it is very nose high getting on the plane although it runs pritty flat once moving and was impressive in the rough on one of the days with abit of water in the front tank

It accelerates mid range like a scalded cat lol

Is this about right and I'm expecting too much or is there something wrong with the setup? I was expecting early to mid 70's

Thanks
Si
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Old 01-06-2015, 08:14 PM   #2
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Quote:
Originally Posted by Toger13 View Post
I have just bought an 21ft bernico believed to be a late 90's hull with a 2008 300xs with a 1.62 sport master fitted with a 24 inch trophy plus

Last week was the first time I got to drive the boat on a flat sea and got to have a play I am very pleased with the boat and love to drive it but I am abit disappointed with the top speed I can't get it over 61mph on the gps at about 5100 rpm I have slowly trimmed it up to the point where I can't turn the steering and have a huge rooster tail just to see what's happening but no gain in speed just more revs and noise as expected when over trimmed lol

This was with no water in the tank and the tabs all the way up

Also I notice it is very nose high getting on the plane although it runs pritty flat once moving and was impressive in the rough on one of the days with abit of water in the front tank

It accelerates mid range like a scalded cat lol

Is this about right and I'm expecting too much or is there something wrong with the setup? I was expecting early to mid 70's

Thanks
Si
Sounds like the motor isn't revving like it should. I'd have thought it would pull more revs with that box and prop on a relatively light hull like that?
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Old 01-06-2015, 08:47 PM   #3
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more speed

Hi you seem way off the mark. You are not reving high enough although your 24 trophy sounds right? Do you know what height you engine is running at as could be too low and struggling. I race in ski racing and this sounds like a f2 boat. Have you any pics of the set up? Low 70's should be easy to achieve.
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Old 01-06-2015, 09:18 PM   #4
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Ye it's an early f2 boat it was Buby Bertels personal boat so I would have thought the height would be some where near the mark although I won't lie to you I don't know

I know he told me he had gone far faster than that in the boat but un sure if it was rigged with this engine and he is a far better driver than me lol

It has had a basic rear bench seat fitted at bernico but I wouldn't expect it would make 20+ mph difference



One think I didn't think about at the time I haven't tried it with out the engine cover on although tuffskinz assured me that the engine will run at max rpm with no issues with it on

Thanks
Si
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Old 01-06-2015, 09:27 PM   #5
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yep

Hi Si I know the boat and saw it when buby had a 2.5 efi on it.. I'm sure the set up is pretty good as it comes straight from Nico. I can't comment on the cover although I would not run it myself with it on as the cowlings are pretty tuned to allow the correct air flow. You are way below the optimum rev range and I'd guess you should need to see around the 6000 mark to be releasing full hp. Good luck and keep us posted with results and defiantly start with removing that cover.
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Old 01-06-2015, 09:38 PM   #6
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Ye I mean the boat handles very well better than I expected having such a weight on the back lol

Max rpm on the serial number sticker is 6400rpm so I'm nowhere near that

I will remove the cover and keep posted it could be strangling it

It's ashame the boat is 300miles from me I want to go have a go lol

Thanks
Si
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Old 01-06-2015, 09:58 PM   #7
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engine cover

you can't simply expect max performance with that cover on unless it has mesh panels over the air intakes, in simple terms you are starving the motor of (cool) airflow. Lose the cover and you will see a big difference..!
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Old 01-06-2015, 10:22 PM   #8
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Ye it has big mesh pannels over the air inlet in the back of the cover

I will remove it and try it anyway it may be as simple as that hopefully :-)

Thanks
Si
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Old 01-06-2015, 10:49 PM   #9
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It sounds like the set up is way off if 61mph is your top speed.
How deep down is your prop shaft?
Do you have a jack plate or is the motor bolted to the transom?

The 300XS should get a 21ft race deck to speeds well above 90mph.
A local P21 does 92mph with a 250XS (1.62 Sportsmaster gear case) with the right prop at a bit over 6000rpm. It's been run with Trophy Plus 27" and 28" at speeds in excess of 85mph.
To reach these sorts of speed the prop shaft needs to be well over pad. However, this set up works in the Nordics where the sea is calm compared to the Atlantic... UK offshore set up is a totally different ball game.

I know there are a lot of guys over here who will tell you otherwise, I can only tell my own experience. The first time I drove the P21+250XS I had the propshaft 1" below pad and the motor trimmed down with a looong water line. Top speed at WOT was 70mph at 5300rpm with a standard Trophy Plus 27". At about ½" above pad and trim just slightly on the plus side, WOT top speed rose to 84mph at 5900rpm with the same Trophy prop. It is amazing what a difference proper set up plays in the equation.
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Old 03-06-2015, 02:09 PM   #10
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Where are you based ? Have you checked that you are getting full throttle ?
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Old 03-06-2015, 06:10 PM   #11
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It could possibly be down a cylinder due to a faulty coilpack, it's been a fairly common problem on 300XS. My F2 Extreme goes quicker with a 115 so something is definitely wrong. Check you're actually getting full throttle too as Bob says, have a friend floor the throttle while the engine is off, have a look under the cowling and make sure the arm can't move any further if you disconnect the cable
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Old 03-06-2015, 07:43 PM   #12
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Hi Guys

Thanks for all the input

I emailed Nico earlier and he confirmed the engine hight and everything is set correctly and the boat should do 80 all day long

He also mentioned as above that with that speed defecate it sounds like it is only running on 5 cylinders

So I will first check I am getting full throttle then go for a run to see if it is any different with out the engine cover off

When the coils go do they misfire all the time or just under load or does it vary?

Thanks
Si
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Old 20-06-2015, 08:51 AM   #13
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Quote:
Originally Posted by Toger13 View Post
..the boat should do 80 all day long...
Exactly ! Get all 6 cyls to work properly mate.

Owner before Bubby was Joachim, and he had also a 300XS on it. Engine before that was a older 300hp tuned Evinrude Vindicator 225 V6. The boat was called "no name" back then. I've added a picture from 2006-2007.

This is a older style 21ft Bernico and this particular one is known to be a very fast boat if it has 300horses on the back ! If you have the exact same setup as Joachim you will fly. Nico most probably delivered you the boat with this or similar setup. So my first guess is something else must be wrong and the 5 cyl remark seems like spot on. Guess you could hear this when it's running bro, some vibration and other sound.

Good luck and have fun !
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Old 20-06-2015, 02:02 PM   #14
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Cheers it's nice to know a it of history

Well I went out in the boat the other day I checked I was getting throttle which I'm probably getting 98% due to some slight wear in the linkage but I don't believe that's the issue I also tried it without the cover on but it was exactly the same I also checked the engine cover foil wasn't covering the throttle but it has been removed already

To be honest it doesn't feel like it's misfiring there is a very light shake at idle but all the cylinders are firing at idle I can disable then 1 by 1 and it does start to misfire the same amount on every cylinder, I got a new coil and swooped it on every cylinder and the slight shake was still there at idle but I ran out of time and didn't get chance to try it on every cylinder under full throttle conditions

I have ordered a new set of plugs and leads to put in it as I don't know how old they are also I have ordered a new transom fuel filter and engine fuel filter for the same reason

I also noticed the coils are all the originals except 1 which was modified type but still a different number to the latest ones so I don't know if I should grab my bag and put a full set of the new number on anyway as I keep reading horror stories of the coils going and taking the engine control unit out too which sounds expensive lol

I emailed rinda about getting a diagnostic machine so I could do some proper diagnosis rather than just guessing but I have not had a reply

One other think I have read is some yellow plastic cap can come off the fly wheel and get wedged in the reed plate so might be worth a look at this too

Si
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Old 29-06-2015, 10:26 PM   #15
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Well at the weekend I fitted a full set of coils new spark plugs new ht leads and fuel filters

I also removed the throttle body and checked the read block which was ok

But it's still the same

Just a side note could some growth on the hull contribute to this much speed loss or am I clutching at straws after wasting 700 quid? Lol

Si
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Old 29-06-2015, 11:45 PM   #16
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How much growth ????

A friend of mine had a 21 ring with 3 inches of weed on it, 20 mph slower !
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Old 30-06-2015, 07:19 AM   #17
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Ye there is no greenery on the hull but it does feel a little rough

Si
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Old 30-06-2015, 09:07 AM   #18
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Sounds like you need to bite the bullet and take it back to Bernico. I know its quite far away but probably still cheaper than the £ 700 youve just wasted.
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