Acceleration problem of KAD300 powered Searay 315DA

[Melida]

Hi all.
I'm registered to the forum by advice of a friend from Club Sea Ray forum site.
I have a Searay 315DA 2005 model powered with single Volvo Penta KAD300 DPG engine. I bought it last year at 135 hours used and now it has 280 hours.
I have more then factory offered option except generator. Such as 50m chain and anchor, spolight, raymarine radar, gps, autopilot, fishfinder, air conditioner, bow thruster, underwater led lights, lcd tv,hydronic heating(bought but not installed yet) etc. Pretty full and seem a bit of heavy but not more then factory specs.
I have C4 prop set and could cruise at 3000rpm 18-20 knots and could do wot at 3900 rpm 32-35 knots according to sea, weather, load and cleanness of hull and leg.
When I full the diesel tank and 2-3 people on boat could not pass 2800 rpm and waits forever.
I searched boatdiesel.com and saw that a few people with same setup of mine in different European countries has the same problem. They solved them by replacing the props with the one size small set C3.
Also I bought C3 prop set but not happy. Because with the small prop set boat planes at 3500rpm at same speed. As KAD300 owners would recognize rated wot is 3900rpm and maximum permitted extended cruise speed is 10% less then wot, so it makes 3500rpm.
With C4 set I could fast cruise at 3500rpm 25-27 knots, so I could not fast cruise with C3 when I need for speed.
To solve this a few months ago I put again C4 set and enlarged the trim tabs. With full fuel, full water and water heater and 3 heavy men onboard
boat did perfect. But with 5-6 people again struggles to pass 2800-2900rpm while the drive is full trimmed in to -9 degree and trim tabs fully deployed. When I gather people at helm or make them sit on vberth engine could reach 3000rpm but not as fast as 2 people on board. But againts strong head winds impossible. Also my boat does not like dirty underwater and leg/props/tabs also now mine is a little dirty.
Tomorrow I'm gonna dive and wipe the hull and brush the leg/props and then test again.
I love my boat and love the easiness of single engine and low cost, bıt I feel its a bit underpowered. I think to repower it with D6-370-DPH but before throwing for that huge money also thinking for chip tuning. I found a few sites offer chip tune-up kits for KAD300. Anybody did or heard about it?
One other possibility(if its possible) heard that opening up/tune up the injection pump could increase the HP and Torque.
Thoughts and comments higly appreciated.
Best regards.
Melida

 

[duncan]

as you have worked out you are basically overloading the boat such that the hydrodynamics of the hull aren't working in conjunction with the engine, gearing and prop gearing.

you are having to compensate by introducing further inefficiency (drive shaft not parallel with water surface) and drag (trim tabs)

whilst tweaking the engine for the occasional additional power might deliver you need the power all the time - sounds a recipe for disaster to me.

so either accept the reduction in speed, re-power - or get a new boat.

 

[ulyden]

With the KAD300 you can cruse at 200rpm less that wot speed. That means that you can cruise at 3700rpm. Its a good rule to keep crusing speed below 10% of wot and new engines like D6 demands it.

The problem you have is well known. KAD 3000 does not have much torque reserves due to hi rating. What i would have done is to move as much weight as possible in front of the boat. Batteries fuel tools everything heavy in front. You can also increase the area of the trim flaps. It helps. Cleaning the hull is good.

If you know a good propeller guy he can adjust the C4 a little bit down in pich.

Dont chip tune your engines. Measure the boost pressure to se if the turbo is optimum.
You can also use a cooler on the diesel to increase the density. Modify the air intake so you get cold air direct to the compressor inlet. That increases the boost.

It could be boost sensor that is clogged and limit your torque. Can you read the boost pressure on your display? Is compressor working?

 

[aquatom]

Dose the compressor cut out? If so dose the turbo take over correctly?

 

[volvopaul]

Dont even think about chipping the engine its well on its limit for cooling the hp it produces now.

 

[CaptainMike1970]

We have a 315DA with KAD 44, 260hp against your KAD 300, 285hp.

Our boat is well specified with all the extras you have plus a tender on davits on the extended swim platofrm and 3.5hp outboard in the engine compartment. We always cruise with full fuel/water etc.

The SeaRay quoted speeds in our experience are a bit optimistic. We cruise at 3200rpm at between 18-22knots depending upon tide/wind/sea, average fuel usage 25litre/hour. Top speed at WOT 3800rpm is 28-30knots.

I have also looked at changing the props and fitting hydofins/hydrofoils to the outdrive to give more stern lift but decided not to do this.

We have found that by moving some weight forward (tool kit now lives under vee berth etc) and keeping the hull, outdrive and props VERY VERY clean with a mid-season scrub the performance is fine.

With more than 3 adults and/or with some hull fouling we use some trim tab and ask people to stand forward by the helm and not to sit on the aft bench until we are on the plane. Once underway experiment with combining some 25%-50% trim tab with some leg trim 0 to +3 and see what works for you.

If you are still not satified some of the last 315DA's were sold with D series engines but an alternative might be getting one with twin 4.3 V6 petrol engines 200+hp each.

Enjoy your boat, they are really super family boats.

Mike

 

[Melida]

Great thanks to all of you especially to CaptainMike1970 have the same boat as mine.

Duncan,

You are right about overloading the boat, this boat can handle ten people according to Searay and with 1-2 gas engine(s) does it. My luckless is not having a D6-310 engine instead of KAD300 while that days newly introduced. So KAD300 is underpowered for this boat and can’t push the more weight.
My outdrive is serviced properly this spring and fully goes to -9 degree and I enlarged my trim tabs, so boat can drop the noise but the power is insufficient to move it further.
I can’t accept this speed because it’s useless and need to do something to get extra power either from current KAD300 or a new engine.

Ulyden, Aquatom, Volvopaul


KAD300 have rated wot 3700-3900rpm. 10% less makes 3500rpm, so continuously cruising at 3700rpm can severely destroy the engine.
If all of the options to get more power from KAD300 would fail then I'm going to depich the C4 set as you mentioned.
I moved all the unfixed stuff to frontest storage areas and do not carry unneeded.
I enlarged the trim tabs and they really helped, also I always keep the hull, leg, props and tabs clean.
I’ll mind your suggestions for the chip tuning.
A new problem arised is engine is not passing 3000rpm now. Speeds up to 2800rpm quickly then very difficultly comes to 3000rpm while there is only me onboard and glass water. Thought that engine was not getting sufficient air however I have more air intakes at sides then the gas versions of my boat also opened the engine hatch to allow extra air but didn’t helped. Heard from a forum a boat owner with MANs faced same because of dirty after cooler and then he cleaned and drained the after coolers and turbo started to work properly.
Compressor is working properly and starting at 1500rpm and stops at 2500-2600rpm and turbo starts. But now around 2800rpm still compressor is acting and there is a very little voice coming from turbo’s propeller/pal like a computers fan or a car engine cooling fan. So turbo is not working.
Tomorrow, Volvo Penta technician will come and clean/flush the after cooler, checking and measuring the pressure of turbo boost, inspecting compressor clutch and disassemble the turbo, injectors and injection pump and take them to workshop and do what they need to fix if they cause the problem.

CaptainMike1970,
Glad to have you on this board owning as same boat as mine. But I’m jealous and can loose my mind. I looked to Searay archives and saw that KAD44 is offered in year 2002 which was 240 hp and later upgraded to 260hp. Your boating style is also same as mine, full diesel, full water, all options also I have 2.4m Bombard dinghy and 2,5hp Tohatsu outboard which makes 40-45kg but don’t have davits. Your engine is doing well and mine is damning me.
Your wot 3800 rpm is in its spec range, so which prop set do you have? Does the KAD44 have same prop scale C2 to C8 like KAD300? If its same my engine have a huge problem.
According to your trim adjustments your engine is running perfectly but burning 25 liters is to much. I cruise at 3000rpm with 18-20 knots and burning 13,5liters while the bottom, drive, props and tabs clean.
I wonder with full fuel and water with how many people onboard your boat could get on plane?
With 6 and full liquids in mid sea condition if I gather people at helm I can get on plane and hold it at 3100-3200rpm by fully deploying the trim tabs and trimming the drive to maximum down.
I can’t imagine my self owning a twin gas powered boat after owning single diesel. It is too difficult to afford in my country.
I’ll keep you posted as soon as VP tech arrives onboard.
Best regards.
Melida

 

[Ianj68]

Hi Melida,

I have pretty much the same setup as CaptainMike. 315DA with a KAD44. I opted for a C3 from new and can report pretty much the same performance figures as him. I tend to find that with clean bottom etc. she will just over-rev, say 3900rpm but with a months or so of growth on the hull this drops to just below 3800rpm. As with you guys I'm carrying a tender on the back and have aircon fitted, usually have a full tank of fuel and water. With that kind weight onboard I don't normally need to worry too much about her getting on the plain. I cruise at 3200rpm which returns about 21kts. WOT gives me just over 30kts (from the GPS)

 

[ulyden]

On these engines volvo says wot-200rpm for crusing. If you reach 3900rpm you can cruise at 3700 according to volvo. But if the engine only reach 3700rpm 3500rpm is max for cruise. Never forget that this is the maximum and correspond to 88% of full power rating. Also remember that its the current wot. If your boat do 3800rpm with no load and 3700rpm at full load the crusing speed is calculated from 3700rpm at full load. Lots of people forget that. Older yanmar engines have the same ruels for cruising.

The D6 310 the continues rating is 90% speed wich correspond to 76% engine power. So the maximum cruising speed is higher on the kad300. Anyway the D6 310 have a much higher torque capasity due to lower spesifik output.

Anyway a good rule is if the boat can not cruise at 10% speed reduction the boat is underpowered. The engine is not new all life time.

So what you have to do. Check your boost pressure. If you only get 3000rpm the boost shuld be 1.4bar g. If that is ok next is the boost sensor. Is this reading correct value? Lots of D4 D6 engines suffer from corrosion on the boost sensor limiting the fuel.

If the boost pressure is low it might be several reasons. Leakage on air or exhaust side, clogged intercooler, faulty boost pressure sensor(smoke limiter)
high back pressure(exhaust) to little fuel (clogged fuel system,filter,feed pump) or defeck turbocharger.

Check your fuel suply. Check your return flow to the tank. At full power it shuld be aprox 50-100l/h. Fuel pressure into the fuel pump 0-3 to 0.5bar g.

To clean the intercooler is a good thing. But its easier to measure the boost pressure after the intercooler first. If this is low, measure before intercooler. If this is high before cooler, clean intercooler. You can also measure the pressure drop with a water gauge. Also try to measure the temperature on the air after the cooler. If yor fingers get burned its not good. Dont try it after compressor. Here the temperature is 140-150deg C.

This engines needs a lot of care! A small engine in a big boat is never good. The engine must be in perfect shape. Use high quality oil and run it slowly up and down in speed. Always heat it up before going to cruise speed.

 

[MarieK]

Ulyden can I ask where you got the boost figures from?

 

[ulyden]

Workshop manual from Sweden.

 

[Melida]

Ianj68
Thanks for your thoughts and contributiıon.
Its good to know Searay 315 with VP KAD44 owners are here.
When I firt read your post demoralized, but later felt happy that when my engine will be fixed then it will done better then yours KAD44.
Best regards.
Melida

 

[Melida]

Ulyden,
Great thanks for your thorough explanation and recommendations.
Today is cancelled because the VP mech gave priority for another customer whose boat was burned sunday and the customer is also at the hospital. So he'll be onboard monday.
I've noted all what you wrote and will be together with the mech to check step by step what you recommended.
I always use genuine spare parts and VP oil and coolant. Always drain the racor fuel seperator every fortnight on summer and replace the filter insert if necessary if not every fuel fill-up. Alway warm up the engine until temp comes to 70 C and wait for the oil pressure drop to 1,5 bar at idle.
One quick thing I do to heat the engine fast is, I have 220volt water heater in the engine room and it is also hooked to the engine's coolant hot water outlet. That means when the engine is running I always have hot water for shower and no need to shore power or generator to heat the water. So before half an hour of starting the engine while connected to shore power at marina I turn on the water heater and then check the faucets if the water is heated, then start the engine and the cold coolant in the engine and hot coolant around the water heater is mixing and while the engine is runing and the water heater is still working on 220volt engine heats quickly.
I do like this maybe its wrong or correct.
Also dont psuh the throttle fast do steady throttle opening and always cruise at cruising speed.
After trip always cooldown at least 5 minutes before stoping the engine.
Best regards.
Melida

 

[Melida]

CaptainMike1970 and Ianj68
Do you have fixed factıry installed (Koehler/Westerbe) generator in the engine room?
If you have how is affecting the weight for the performance?
Just wondering.
Best regards.
Melida

 

[Melida]

Hi all with a little update.
Yesterday the weather was cold and rainy and the Volvo Penta mech said he was able to get onboard.
I cruised 20 minutes from my summer place (island) to my winter marina. The wind was blowing 5 Beaufort from north which I was going towards; engine difficultly reached 3000 rpm while there were ¾ fuel and ½ water and only me onboard. A few minutes after reaching cruising speed I hammered down the throttle and engine reached 3300rpm and I raised the drive to +5 and reached 22knots. Boat was cruising nice until hitting the wake of speedcat and revs dropped to 2800. Lowered the drive to -8 and deployed fully the tabs engine gradually reached 3100rpm and got on plane.
When Volvo Penta mech came onboard and he disassembled aftercooler, air inlet and air divider for compressor and turbo, turbo and injectors.
As seen in the below picture aftercooler seem pretty clean although he will clean/wash/flush it.
http://i998.photobucket.com/albums/...cooler and turbo maintenance/050920101130.jpg
He removed the air filter and checked air intake while the engine is running at 1500rpm idle was no air intake restriction.
http://i998.photobucket.com/albums/...cooler and turbo maintenance/050920101131.jpg
After removing the air intake side of turbo it is visually seen oily and dirty.
http://i998.photobucket.com/albums/...cooler and turbo maintenance/050920101132.jpg
http://i998.photobucket.com/albums/...cooler and turbo maintenance/050920101133.jpg
Also he drained the coolant/antifreeze which is nearly 2 years old and disassembled heat exchanger and will clean it.
Today he brought the injectors for test and cleaning to Bosch service and called back. Injectors made mammas at their edges and cleaned. According to the engineer at Bosch the injection pump could cause a failure, but the replacement parts of it takes a month to bring. So it will be fixed later if this whole repair dissatisfies me although I have to wait for the parts.
Also turbo went to the turbo shop. Mech said it is cleaned and repair kit must be replaced, but there was no major wear on the prop shaft of turbo.
Tomorrow he will put together all of the disassembled parts and fill the fresh water cooling with new coolant then gonna do sea trial at 6pm.
Do I miss or forget something to do about performance recall?
Hope to hear from diesel experts.
Best regards.
Melida

 

[Melida]

A late hi again with a little update.

As you’d remember late summer Volvo Penta mech came and checked every part of engine could cause the performance lack and minimized the problem to injectors must be changed, at least the nozzles and checking the fuel injection pump why not pumping effectively.

While this problem arised I had ¾ tank of fuel and until the end of September I was happy with my boat’s performance b/c since the level of fuel decreased performance increased.

When I bought/buy fuel and every time I fully fill my tank to calculate the average consumption by dividing the hours to quantity of fuel bought, also drain the racor bowl and change the 10 micron filter element with a new one. This leads to introduce air in the fuel line and I bleed the fuel system by manual hand pump until the bubbles disappeared and only fuel is coming. After this if I’m at summer home cruise to gas station for 15 minutes on plane or in winter marina 5 minutes of no wake zone. After filling fully tank (last two fill ups from a tanker not the constant tanks of gas station) engine had difficulty to reach 3000 rpm (which is my sweet spot) after a few try and than fine. First I thought I couldn’t successfully bleed the fuel system but I cruised 15 minutes on plane from island to city, so bleeding was perfect and there shouldn’t be any air in the fuel system. So the weight issue creates the lack of acceleration after filling the tank, or the tanker had too much debris in the fuel that I bought.

Called again the mech and told the whole story. He answered me that fuel pump can not pump effectively and nozzles must be changed. I got price quotes from Volvo Penta Turkey, Greece and USA for complete injectors set which even from USA the cheapest will cost me 2620 USD for 6 pieces from online. Than looked to the exploded scheme of fuel system there is an opportunity to by “exchange” injectors as a friend suggested. They are 100 USD cheaper than complete injector and I’d save 600 USD totally. BUT mech warned to buy the complete injector instead of “exchange” b/c it means fixed, so they are also had failure in the past and fixed but have not guaranty to won’t fail again. So have to buy complete new set.

A week ago mech called me and gave good news. Bosch is selling nozzles and I don’t need to buy exchange or complete injectors and he ordered them. After that mech came to boat and disassembled the 6 injectors and fuel injection pump and brought them to Bosch service. The engineer of Bosch service told that they have the nozzles on the way and 6 of them will cost me 475 USD and they exploded the fuel pump and gonna inform me today or tomorrow what’s wrong with it.

A member from an other forum asked “Engine run fine and injectors need replacement? How can it be? Did you experienced smoke or have fuel sludge from the exhaust??? “And I replied no smoke or fuel sludge that time. But nowadays or at least last cruise I did two weeks ago when I started the engine after a two weeks running there were a little rainbow on the sea surface coming from my boat. That is the sign of dead (almost) injectors. But after a 20 minute cruise when anchored there was nothing visible but exhaust smoke was seen and smell.


An other member said “I don’t think they are serviceable by any Bosch diesel / truck specialist as they are quite complicated 2 stage units, so you have to replace them” but if I buy an exchange injector they want my complete injector(s) and they’ll only change the nozzles so the core part is same, also I have no failure on the core parts of injectors, just the nozzles have gone. An easier explanation is they sell nozzles with the price of nearly complete injector and it is not zero/new nozzles. So why would I pay 2620 USD for fixed and not guaranteed replacement instead of zero nozzles for 475 USD and just in a few days of delivery instead of waiting someone brings me from USA within a 1-2 month? Bosch have ordered the nozzles and they’ll perform the changing tomorrow and they have lots of parts which fuel pump will need and gonna reach for Friday. Also he ordered the “Boost pressure sensor” but not reached yet.

Asked to mech/Bosch as an other member asked “Can't they be rebuilt? If they need to be new, are they going to be the same or can they be larger to get more HP out of the engine?” They said no rebuilding but exchanging as I mentioned above. Also have to buy/put the same size of existing injectors. To get more power/HP must enlarge the fuel feed, injection pump, air intake, turbo and exhaust so they all mean a different/bigger engine and KAD300 have no room to enlarge to perform these.

On Friday mech came onboard and put what he disassembled. Injectors with new nozzles, fuel injection pump cleaned which had fuel dirt and put new repair kit. Then we did sea trial. In the lower revs engine was very fast to reach 2500 rpm, and compressor cut off (screaming noise stopped) and turbo started. But again rev reached and waited at 2800. After a few minutes suddenly rev increased and did wot.

Tomorrow or weekend if the weather permits will do again a sea trial with VODIA attached to engine to see whether Boost pressure sensor or/and Charge air temperature sensor are defective as Ulyden suggested when I first started this thread, also are needle lift sensor, engine coolant sensor and engine speed(rpm) sensor show any defects.

I searched the forum and read the thread (http://www.ybw.com/forums/showthread.php?t=246711&highlight=KAD300&page=2) of the member “Eastbrae” (similar problem to mine) who solved problem of his KAD300 by replacing the air inlet sensor.

We tried/inspected/cleaned/serviced/replaced every possible part of the engine which can cause lack of performance and minimized them with these sensors.

Any suggestions greatly appreciated. Thanks in advance.

Wish me luck.


Best regards.
Melida

 

[gjgm]

Do you really need all that chain, and to drive around with full fuel and water tanks?
I'd have agood think about what you dont need on board as a cheap start...I'm sure it wont cure the problem, but it might help.
I cant beilieve what I seem to have acumulated on board by the end of a season !

 

[Melida]

Thanks for the reply.
Since the engine is diesel and I'm averaging 13,5 Liters per hour takes 26 hours to finish the tank.
Also where I boat sometimes have to anchor at deep.
Best regards.
Melida

 

[gjgm]

Thanks for the reply.
Since the engine is diesel and I'm averaging 13,5 Liters per hour takes 26 hours to finish the tank.
Also where I boat sometimes have to anchor at deep.
Best regards.
Melida

13.5 LPH...you must be going really slow !

 

[Melida]

13.5 LPH...you must be going really slow !

It's cruising consumption at 3000 rpm with clean bottom/leg/tabs/props and speed between 18,5-20 knots.