Loss fo Performance and Efficiency

[Laveread]

Here is the history to help you better understand what has happened.<br /><br />About 6 months ago I had to send my new 2003 Pro Sports 2550CC back ot he manufacturer because of some hull problems. Their solution was to build me a new hull and deliver it back to me with all the original equipment including the motor, a single Yamaha 4 stroke 225hp. Before getting the new hull I could cruise at an easy 32kts at appx. 4,800rpm and WOT I could get to 42-43kts. these speeds were taken off of my GPS. Now that I have my new hull I am only capable of cruising at 28kts at 4,800rpm with a WOT speed of about 34kts. The overall efficiency has decreased at least 35% - 40%.<br /><br />The first thing I had to do was to lower the whole motor to the last hole on the mount to get the motor further down into the water as it was before. I didn't see any noticeable difference doing that so I have tried numerous times to contact Pro Sports asking their advice but I could never get a response. Now I am frustrated to the point that I do not enjoy my boat anymore. I have considered contacting an attorney to get Pro Sports to correect the solution. This is not the boat I bought from them one year ago!!! All I want is the performance and efficiency I had before, you know....the two factors that greatly influence someone into buying a specific boat. Before I go that route I want to exhaust every avenue I have first.<br /><br />Ok, after that long discertation here is my question. What could it be? The motor runs great as always. Could it be that the hull is different then the original? Could it be that the boat is that much heavier? Pro Sports said they were going to re-enforce the new hull for me which of course would have made it heavier but it could have increased the weight that much? Do I need a new prop? If so, what is the best way to determine what size prop I need without going through trial and error and having to pay the usual $50 restocking fee for every prop I try out?<br /><br />Any suggestions are welcome!!!!

 

[jim dozier]

Re: Loss fo Performance and Efficiency

Explain again in more detail why you had to lower the engine further. If the engine did not need to be lowered, doing do will decrease your speed. The anti-ventilation plate on the engine should be essentially even with the bottom of the boat. Did they provide a new hull or just fix you old hull? Have you examined the "new" hull? Find out exactly what they did differently. Can they estimate the increase in weight? You have a long list of things to investigate before you re-prop the engine but eventually you will need to do whatever is necessary to get the engine up to its proper rpm range including looking at hull mods, trim mods, raising the engine or a new prop.

 

[Laveread]

Re: Loss fo Performance and Efficiency

I lowered the motor initially because my performance was not what it was before the hull replacement. I also lowered it to put it back in the same position it originally was on the old hull. I'll check the position of the anti-ventilation plate and if it is not placed properly I'll change the engine position.<br /><br />They did in fact replace the old 2003 hull with a new 2004 hull. To my eye there is no difference between the hulls. Since they said they were going to add re-enforcements to the new hull I figured the weight would increase some but not enough to cause a 20% decrease in performance and a 35% - 40% decrease in efficiency. I could try and contact them to ask them about the increase in weight but since I have tried to contact them nearly 10 times with no response I feel I would get the same...no response.<br /><br />Excuse me for being ingnorant here but what do you mean by hull mods and trim mods? I have hydraulic trim tabs and have experimented with every trim combination of the tabs and the motor combined but still I am at a loss for performance and efficiency.<br /><br />Could you tell me what the proper RPM range for the Yamaha 4 stroke 225hp motor is? When I bought the boat and test drove it I was told that 6,000rpm would be the max operating range and that is what it would run WOT before the hull replacement.

 

[jim dozier]

Re: Loss fo Performance and Efficiency

When I said hull mods I was referring to the possible need to fix something in the hull if they had screwed up, hopefully not the case. What hull problems prompted you to take it back to the factory in the first place? You seem to have experimented already with the trim. I don't know for sure but ~6000 rpm max sounds about right. What is the max rpm the engine hits in its current configuration? If you can't get what you used to in terms of rpm, you may need to go to a different prop. Can you verify that they did not change the prop from your original while they were working on it. While you are at it, are you sure the engine is the same (serial #)? It does seem odd that you would loose so much speed with a little extra glass and resin in the hull. Check to make sure there isn't an accumulation of water in the hull somewhere also.

 

[BRIAN03]

Re: Loss fo Performance and Efficiency

Do you know if you have the same prop back on the engine. Check the hub in the prop if it has a rubber hub. Could someone have switched props. I would start with the prop.

 

[Laveread]

Re: Loss fo Performance and Efficiency

I took the original hull back because of some cracks appearing in the forward portside of the bow plus the deck cracking where the t-top was bolted to the deck. Final determination was a stringer had busted loose from its position. The cracking on the deck was from no re-efnorcements where the t-top was bolted down.<br /><br />Top RPM now is 5,400 - 5,500. It is the same motor and prop as before. I know my answers may be somewhat frustrating you but believe me I have been 'round and 'round on this and have tried and thought of just about everything except a new prop. <br /><br />Thanks for your patience and ideas. I will re-check the engine and prop to be sure the originals were given back to me.

 

[Solittle]

Re: Loss fo Performance and Efficiency

What do you mean by "The overall efficiency has decreased at least 35% - 40%."?<br /><br />Forgetting what the GPS says - Does it "seem" to handle/perform anything like the old hull? Maybe a stretch but I'm thinking maybe the speed difference is some kind of GPS issue. I suspect that jimd has it nailed with the height of the motor.

 

[Laveread]

Re: Loss fo Performance and Efficiency

With the loss of performance I suffered a loss in efficiency. By that I mean that my normal cruise of 32 knots at 4,800rpm gave me about 2.6mpg and now it requires 5200rpm to attain 32kts which gives me about 1.7mpg. For me to reattain the 2.6mpg mark I have to reduce my speed and rpm to appx 23kts at 4,300rpm.<br /><br />No, the boat does not perform as it used to. It is sluggish getting out of the hole and top speed has obviously reduced. Furthermore, I am not able to turn at any high speed without the prop "blowing out". If I try to gun it out of the hole I get too much ventilation or cavitation, whichever it may be.<br /><br />I would have to disagree with your assumption of the GPS being wrong. My speed reading between the boat's readout and the GPS are consistent with what it was before. Also, deadreckoning and "time/distance" calculations are right on.<br /><br />In response to jimd and Brian03, I rechecked the motor and prop and they are the same.<br /><br />Is it time to go to an attorney and let him hammer this out with Pro Sports?

 

[v12mac]

Re: Loss fo Performance and Efficiency

Where has your dealer been throughout this? What do they show for performance stats with your new setup? Can you hop in a dealer demo with the same set-up and check WOT speed, RPM and prop? <br /><br />The dumb question:<br />One other question is there any chance of a Knots vs MPH error?<br />Lets look at a scenario: You stated that your old WOT was 42 knots and now you only get 34 knots. Is there a chance that you were gear was reporting in MPH and now with the reinstall you are reading in Knots? The old WOT of 42 Knots if looked at as MPH you get 36 Knots (42mph=36knots). With the engine position off a bit you loose 2 knots and there is your new 34 Knot speed. <br /><br />What was your WOT rpm before and after?

 

[Laveread]

Re: Loss fo Performance and Efficiency

m ydealer was the first person who lowered the motor back to the original position. Actually it was the mechanic. A very well known and respected Yamaha Master Mechanic. He was a little miffed that when the boat was delivered back to me it was not delivered in it's peak setup. He has talked to them in the past about the best setup for that motor/boat combination. Anyway, I have since moved and am now not near my original dealer or other Pro Sports dealer that is why I am have tried to deal with the manufacturer but to no avail.<br /><br />I wish it was as simple as to say that it is a reading error in the instruments. It is not. I can feel a noticeable difference in the top speed as well as the acceleration. The other differences I listed in my last post.<br /><br />WOT before was 6,000 with best trim dialed in for max speed. Now it is 5,400 - 5,500 at best trim.<br /><br />Thanks for your first suggestion. I guess my next step is to haul the boat to another Pro Sports dealer and take one of his boats out for a demo then take him on my boat for a demo. Let him see the difference and if I don't get some sort of satisfaction then I willo be left with no other choice but to pursue this through legal channels.<br /><br />Its just a shame that the boat I once had and enjoyed so much is now a boat that I am ending up hating.

 

[Dhadley]

Re: Loss fo Performance and Efficiency

Since the rig has lost performance across the board -- from acceleration to top speed -- it may be that the motor is no longer performing at its best. You lost 500 to 600 rpm on top. That is exactly what a loss of spark on one cylinder will do on a V6. If its performing on 5 cylinders that would explain the other symptoms also. Perhaps the linkage is not getting to full advance.<br /><br />Yes, there may be some small differences in the hulls. Weight, hook etc. Raising the motor should raise the top rpm. Lowering the motor should have dropped the rpm. Perhaps when the factory re-rigged the motor it was running on 5 or the linkage was off and they raised the motor trying to get the rpm up. When it didnt happen they simply shipped the boat back. They, most likely, are not outboard master techs and Im sure you were anxious to get your boat back.<br /><br />First of all lets seperate the boat and motor. Run the motor with a test wheel. If it gets the correct rpm, then we can eliminate the motor as the problem. If the rpm's dont come up on the test wheel we can eliminate the boat as the problem. Very quick, very easy.<br /><br />Let us know how you make out!

 

[Laveread]

Re: Loss fo Performance and Efficiency

Dhadley,<br />Although the motor sounds ok while it is running I like your idea of one cylinder not firing as long it is something as simple as a bad plug or wire. It is due for it's regular scheduled maintenance so I will just tell the mech to give the motor a good look over drawing his attention to that possibility.<br /><br />Although I had thought of a bad cylinder I dismissed it since when it went back to the factory it was running great. I have assumed all this time that it had to be something else. I will certainly keep you posted of the outcome. In fact I am going to check if the cylinders are firing this afternoon on my own. If they are all firing then I go back to square one. <br /><br />Cross your fingers.

 

[Dhadley]

Re: Loss fo Performance and Efficiency

Actually the more I think about it the more I lean toward thinking the linkage may not be going all the way open (maybe 3/4 to 7/8?). That would explain the "sounds good, runs smooth but no guts" deal. Especially if the riggers are not familiar with the motor you sent. Like putting a block under you cars accelerator pedal. It runs good, it just wont go.<br /><br />The test wheel thing will eliminate one or the other (boat or motor) real quick. <br /><br />Good luck!

 

[Knightgang]

Re: Loss fo Performance and Efficiency

Tony,<br /><br />I think Dhadley is onto something with the linkage. The timing on outboards advances with increase in throttle. If the linkage is off, it may not advance enough and could cause the lack of power. The only way to test this under load (which is where it counts) is with a test wheel or in the water. I had a bad plug cap on my boat and it only showed up as a problem when running over 1/2 throttle. It would cause a skip, but I have a four cylinder, your six may not have a noticable skip, but will show the loss of power.<br /><br />Good luck

 

[Laveread]

Re: Loss fo Performance and Efficiency

Dhadley,<br />After thinking about it more your explanation would explain power loss and associated with that the loss of efficiancy too...right?<br /><br />Read my 4th post again. Would that explain the "blow out" in the turns and excessive ventilation/cavitation? Let me add one more thing here. I get "blow out" running through somewhat rough seas (3ft+ seas) which I didn't suffer before.

 

[Dhadley]

Re: Loss fo Performance and Efficiency

Did you experience the cavitating after the motor was lowered?

 

[Knightgang]

Re: Loss fo Performance and Efficiency

Does the new hull have the same degree of deadrise at the transom. If not, that could explain of the the cavitation.

 

[Laveread]

Re: Loss fo Performance and Efficiency

Yes, to lowering the motor. I can't recall if it did it before lowering the motor since I only took it out once before having it lowered. All I know is that the performance was reduced so the mechanic made the adjustment as he did when setting up the original hull when it was delivered to me new.<br /><br />I would have to say "No", to the deadrise. In the manufacturer's specs there was no difference between the 2003 and 2004 deadrise angles.<br /><br />I just did the best research I could using Pro Sports website. The closest hull to mine would be the 2250WA. Although this hull is 3ft shorter it has the same deadrise, its 200lbs heavier and has a 1 inch deeper draft, same beam etc. Top speed for the 2250WA is 49.8mph at WOT, 6,000rpm. Giving my boat at the longer length yet lighter in weight, same dearise, same beam and so on....would you figure that I should be getting close to the same speed? Am I reaching for strings here? I know that the original boat was very close to that if you convert my posted kts to mph.

 

[Laveread]

Re: Loss fo Performance and Efficiency

I forgot, the 2250WA was tested using the same Yamaha 225hp 4 stroke motor.

 

[Dhadley]

Re: Loss fo Performance and Efficiency

Bummer. I was hoping the cavatation was when the motor was higher. Perhaps we have two issues going on here. The cavatation issue points directly at the propeller. Cavatation is usually a by product of the props lack of ability to "bite" at a given X dimension. But less "bite" usually means more top rpm (and limited useful positive trim) although speed could drop off. You mentioned before that you are positive that it has the same prop. Is it simply the same kind or is it truly the exact prop that was on the motor? Are there any numbers stamped in it that indicates a rebuild?<br /><br />Anyway, lets focus on the power issue. We can deal with the prop/cavatation issue later. Get the dealer to run the motor in the water with the test wheel. Lets see what the rpms come to. Dont forget, this is a test wheel. The rpms may not necessairly come to 6000. What we're looking for is what the factory manual calls for. It may be 5200 or 6200 or ????. If the rpms fall short, we have a motor issue of some kind.<br /><br />Hang in there!