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Hello... I'm the happy owner of a 265 SSI 2002 model. But I feel the boat is much slower than it should be. It's powered with a Volvo 5.7 GXI which I believe is putting out 280hp.  At full throttle I'm maxing about 34 on my GPS.  

The props are in good shape. But I'm not sure of the pitch.  It's has DPS.  The prior owner put a hydrofoil on the outdrive.  It gets right on plane.  It's been serviced by a professional mechanic every year.  

Anyone else with the same boat that can chime in?  

 

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What is you WOT RPM?   A hydrofoil helps with initial stern lift reducing time to plane, but it can also make your ride bow steer at or near top speed. Lets start with WOT engine RPM, as you should be seeing something just short of 5 grand.   Is the hull slick and clean? Slime layer increases surface tension greatly and tends to "glue" the wetted hull surface to the water.   W

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That is slower than expected.  I would expect low 40's for that size boat with only a 5.7. As Wingnut commented, what is your RPM @ WOT. Need to determine if it is a mechanical issue or something else, like a dirty hull bottom. Any chance you were running upstream against a 10mph current?

brick

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just got rid of a 2002, my GXI-C with duo prop was rated at 320hp.  Maybe yours is less I don't know.   Boat is supposed to run in the 4500-5k rpm range at Wide open throttle. If its not a few things to look at, prop, is the hull clean, engine problems.  My 265 I had F6s on it, it had F4s on it and I gained a couple mph by going up,  When I called chap they said the boat came from the factory with F6s.  So I would imagine F5s or F7s should be good. My boat I was able to turn 4400rpm and get about 44mph.  Although I tinkered with it a little trying to get some more as looking around the boat should have turned 5k and probably got close to 50mph.  Boat like that I would expect 45-50 depending on the load.  If you have less hp than maybe less.

 

So yes I would check the prop, check the hull if full of barnicles or bottom paint is bad, it needs to be redone.  As far as the engine, probably time to check the plugs, if they look like they need it, then do the plugs, wires, cap and rotor, all can be done in an hour or two with around 100 bucks( might be just worth the time and money to do it and rule it out).  Next fill her up with gas some star tron and go for a run, more than like the three issues I mentioned will cure it.  If not a few common problems on this boat is the fuel pressure regulator  which is to the right of the flame arrestor, little round piece with a hose going into it.  Pretty easy to check, turn power off to the pump pull the pin out from the top and look at it, if theres a screen on it might be clogged, clean it or look for the Volvo clip to replace the screen.  otherwise that's a 150 buck part.  Next issue with these is the fuel pump, which is an 800 buck part.  personally I would do the tune up, check the hull, check the prop, if that doesn't fix it, check the fuel regulator.  still doesn't fix it, instead of throwing 800 bucks at parts, probably time to have it checked out.  Could be the IAC too forgot to mention that.

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Oh if your monkeying with the fuel system your suppose to depressureize it,  which is simple just loosen the fuel filter quick.  Also after everything is put back together turn the key till the pump comes on 5-6 times, on and off before you start.  Also if you take the fuel pressure regulator off have a rag underneath some fuel will come out.

 

I will also mention probably replacing the fuel filter wouldn't hurt, just be sure to fill the new one up half way before installing, and again turn the key off and on 5-6 times.

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I have a 383mag stroker 350hp, the very best I have managed is 49.84 knots on the GPS. Half a tank of fuel exhaust open and one other person in the boat ( with a pc connected to the Ecu) Nothing else in the boat. Fuel burn rate at that speed was 84 litres per hour.

But to be honest most of the time we run around at 3200rpm 23/24 knots approx 34 litres per hour with a boat half full of stuff.

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WOT is around 4700/4800

Hull is bottom painter and certainly has growth by this time of the season however I've never seen speeds in the 40s. 

Plugs, rotor and cap have all been recentl changed. 

Boat at runs great but obviously slower than expected. Maybe a soda blast is required this winter before the seasons new coat of bottom paint?  

 

Some great helpful ideas here.  My regular mechanic is a merc guy. He has a great reputation and I've worked with him for years, therefore he continues to service me even on my Volvo. But he is not a performance guy nor does he have advice on prop type and bottom condition.   

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32 minutes ago, DJmike007 said:

Ok.  So this winter then calls for a professional bottom clean and paint. Hope that does the trick. 

Have your mechanic do a leak down test on your engine just to be sure your not loosing power somewhere else. You have a heavy a$$ boat and over time along with the build up on the haul it puts a lot of added stress on that small block Volvo. Good luck. 

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As suggested before in this thread, the F6 is what most likely came with this boat, or the F5 as it could be more suitable for overall good performance with a 280hp engine, but the F4 is not aggressive enough. The F4 gives you a great hole shot but it compromises the top speed.

I would suggest trying the F5 before committing to F6. Test the props with clean bottom, well trimmed drive and trim tabs.

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  • 4 months later...
On August 18, 2016 at 10:49 PM, DJmike007 said:

Just found receipt for prop when replaced. I have an F4 size. Is this appropriate?

RPM's are where they should be. 

 

What elevation are you at?

brick

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F4 is low and suspect was used for watersports or trolling maybe.  F5s or F6s should net you another 2-300 rpm and 2-4mph.  My guess though is if your gauges are all right and your turning the correct RPM its a dirty hull and improper trim techniques.  Might want to check your engine a 5.7Gi has 280, gxi is 320.  With a loss of 40hp and probably equal torque I don't see you sniffing much past 40. But I would think you should be in the 38-40 zone.  simple prop change and or a hull cleaning will net you that.

I had one of these problem is its a fantastic boat in terms of layout and such, just doesn't have much speed,  at 5500 dry and deep hull it probably needed to come standard with a big block.

 

Per the specs if you have the GXi it should turn I believe 4600-5200.  If you have the GI maybe less.

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