Turbo problem....

[Asureyez]

After coolers cool down the super hot compressed combustion air coming from the turbo to the cylinders. Cooled air further compresses the air pre combustion allowing for more bang for the buck.

IF the after coolers are fouled, the engine gets raw hotter air and but produces a leaner air to fuel mix. This means more carbon build up as seen in these turbos, higher exhaust temps as seen in the burnt vanes.

Peek inside the coolers and I'll bet a beer they are fouled with crude. Most common fouling can come from Airsep crankcase oil recovery system failure and blowing carbonized oil vapors and condensates in to the cooler.

These turbos may qualify to be rebuilt.

 

[OldSkool]

Richard, Wish I knew you were in Greenville. I live about an hour away up in Hendersonville, NC. I would hav liked to met you. Oh well maybe next time.

I don't have any word on your issue yet but I will investigate it.

 

[melida]

After coolers cool down the super hot compressed combustion air coming from the turbo to the cylinders. Cooled air further compresses the air pre combustion allowing for more bang for the buck.

IF the after coolers are fouled, the engine gets raw hotter air and but produces a leaner air to fuel mix. This means more carbon build up as seen in these turbos, higher exhaust temps as seen in the burnt vanes.

Peek inside the coolers and I'll bet a beer they are fouled with crude. Most common fouling can come from Airsep crankcase oil recovery system failure and blowing carbonized oil vapors and condensates in to the cooler.

These turbos may qualify to be rebuilt.

+1 about the after cooler.
It proves what Terry faced with his engine. He cleaned his heat exchanger and his overheating disappeared while visualy heat exchanger seen very little dirty. Where the sea water passes is very tiny holes and they are prone to be clogged if not inspected/serviced frequently. The owner's manual says 5 years for this but it not suits for real life in the harsh sea environment.

 

[Richard F]

Richard, Wish I knew you were in Greenville. I live about an hour away up in Hendersonville, NC. I would hav liked to met you. Oh well maybe next time.

I don't have any word on your issue yet but I will investigate it.

Hi OldSkool, I was in Hickory visiting a customer two weeks ago......next time we'll meet up!
Richard

 

[Richard F]

After coolers cool down the super hot compressed combustion air coming from the turbo to the cylinders. Cooled air further compresses the air pre combustion allowing for more bang for the buck.

IF the after coolers are fouled, the engine gets raw hotter air and but produces a leaner air to fuel mix. This means more carbon build up as seen in these turbos, higher exhaust temps as seen in the burnt vanes.

Peek inside the coolers and I'll bet a beer they are fouled with crude. Most common fouling can come from Airsep crankcase oil recovery system failure and blowing carbonized oil vapors and condensates in to the cooler.

These turbos may qualify to be rebuilt.

I had the coolers out and had them cleaned 3 months ago. They were in good shape. Just a very little dirt, no blockage. Engines only ran about 5 hours since....... shall I take the inserts out again to see?

 

[Richard F]

+1 about the after cooler.
It proves what Terry faced with his engine. He cleaned his heat exchanger and his overheating disappeared while visualy heat exchanger seen very little dirty. Where the sea water passes is very tiny holes and they are prone to be clogged if not inspected/serviced frequently. The owner's manual says 5 years for this but it not suits for real life in the harsh sea environment.

Melida,
Thanks for reminding me.....I haven't checked the exchangers yet. May be I should do that quick. I might have the same problem Terry had!!
Richard

 

[melida]

Melida,
Thanks for reminding me.....I haven't checked the exchangers yet. May be I should do that quick. I might have the same problem Terry had!!
Richard

Richard,
It's good to hear from you again.
One of the major reason for the overheating is blocked heat exchanger and then worn impeller and so.
Please do that favor for yourself and clean the heat exchanger, oil cooler, aftercooler, power steering cooler and check/clean the sea water inlet hose.

 

[Lord Farringdon]

Hi guys,

If that's caused by mechanical should that be there everytime not one day there and one day not there? I also notice one thing that everytime when i open the filter lids, the port side "cup" is full of water (feel like a close circuit) and then water slowly goes down. But on the other engine, there is no water held in the "cup" and the lid can be lift off easier. Any suggestion? VP changed the water pump implers at the 200 hrs service and now is about 270 hrs.
Will catch up with you guys on the rest of the things.....

Richard

Hi Richard, good to hear from you again. These overheating problems are a pain aren't they? I suspect you may be going through the same problem as me, that is two entirely seperate problems coming together at different times and making diagnosis confusing. :smt101

What you have noticed about the seawater filters is very important. You obviously have some problems with algae in your area and you regularly check your seawater filters. That's a good thing. But that may also be one of your problems. I had an overheating problem almost the same as yours. If I ran the engine at displacement speed no problem but on the plane at 3200 rpm, the engine started getting hotter the longer I ran it. eventually it would reach over 210 degrees. I would stop (engine idling) and let it cool down and then carry on. Then one day, I had barely got out of the marina before the overheat caused coolant to splash out of the expansion tank cap. :smt021

Despite talking to my VP techs, there was no immediate answer. So, I researched this myself and I noticed the same thing as you. When I unsrewed the seawater filter cap, the lid was hard to pull off but once off, the water fell down below the "cup". It depends on how high(or low) your engines are mounted in the hull in relation to the waterline, but I found I could look down the "cup" into the inlet pipe and see that the water had descended so far down that the impeller was DRY! I mentioned this to someone who said "no problems, the impellors in these motors are self priming". I researched this and found that a self priming impeller will take a water/air mixture and prime the air out so it is running with water alone but it must have some water to start with. That is to say, a self-priming impellor will not suck a vacuumn and bring water up from some distance below it. It must be at least partially immersed. I had checked the filter everytime before I started the engine and everytime I had felt the suction that prevented the lid from coming off. Yet everytime I put the lid and cap back on, the impellor was now dry. In hindsight I now realise that my engine used to heat up quite quickly as I slipped out of the marina at two knots. Once I got into open water the boat sloshed up and down and water reached the impellor triggering a self prime. But on this one ocassion it did not and the early overheat was the outcome. So, what I do now is still check the seawater filter every trip but I top up the "cup" with freshwater and quickly put the lid back on. Immedialtely after start I place my hand on the impellor housing/faceplate and check it is cold. This tells me the impellor is primed and sea water is being pumped through the engine Overheat problem No 1 solved.

" But on the other engine, there is no water held in the "cup" and the lid can be lift off easier"

If this happens then it means there is air in your seawater system and this can't be good for the temperature.Top up with freshtwater and put the lid back on firmly.

Edit : (is there a crack in the lid or your cap?)

Outside of this, you still need to check the heat exchanger and the oil cooler for your other overheating problem. Then, if the problem still exists consider other issues.

It gets messy doesn't it?



Hope this helps.


Terry Hay

 

[Richard F]

Guys,

Done as you guys advised over the weekend. The port engine definitely shown an improvement. Temperature hangs around 180 degree. This is the engine I could feel the "vacuum" when I open the lid. There is no much difference on the other engine. I don't feel any "vacuum" even I swapped over the lids. I don spot any cracks anywhere. The water seems go down quicker than the port side when I filled the cup with fresh water. I have used the hose to blow down the engine side of the sea water cooling (not the impler side) and it seems flowing quite smooth. But the temperature still stays at around 200 at crusing (2500 ~ 3000 rpm). I didn't try any WOT condition because of the weather.

Forgot to show you guys about the "chip" and "hole" on the prop.....do you think they are significance?

Richard

 

[melida]

View attachment 18925View attachment 18924Guys,

Done as you guys advised over the weekend. The port engine definitely shown an improvement. Temperature hangs around 180 degree. This is the engine I could feel the "vacuum" when I open the lid. There is no much difference on the other engine. I don't feel any "vacuum" even I swapped over the lids. I don spot any cracks anywhere. The water seems go down quicker than the port side when I filled the cup with fresh water. I have used the hose to blow down the engine side of the sea water cooling (not the impler side) and it seems flowing quite smooth. But the temperature still stays at around 200 at crusing (2500 ~ 3000 rpm). I didn't try any WOT condition because of the weather.

Forgot to show you guys about the "chip" and "hole" on the prop.....do you think they are significance?

Richard

Richard,
Goodmorning, at least it's 08,40am here.
All you need to do is as many times I and Terry suggested to you is disassembling and cleaning,flushing both heat exchangers/coolers for either engine.
On the other hand for rpm issue pics says the answer. Think about lower piched prop gives you less wot and higher piched prop gives higher cruise and wot speed. So any lack of prop will reduce your rpm and speed because of less prop surface. Altough you must hearing a vibration/cavitation noise. If you fix that prop you'll feel the different healthy sound from the props.
You can fix those props. They are SS and weldable in a good prop shop. If you had D4 D6 series engine with DP-H drive, they have nibral props and difficult or impossible in some situations to fix/weld.
Hope this helps.
Please show us more photos of your beatifull boat and boating area.

PS: The prop in the right pic is dirty, even it has antifouling. Do clean it with #80 sand paper and then prime and paint it. If you read my acceleration problem thread I solved it mostly by keeping the props and hull as clean as possible. I was surprised how boat reacts and didn't planned with little dirty props like in your pics and when I sanded them how surprising the boat flys like a gas powered boat.

 

[Lord Farringdon]

View attachment 18925View attachment 18924

Forgot to show you guys about the "chip" and "hole" on the prop.....do you think they are significance?

Richard

Yes they are Richard, very significant. Read this from Stingray Powerboats website:

Essential to good propeller maintenance is periodic inspection to detect even small dings, which can lead to blade failure if not dressed or repaired. A damaged propeller, even one that only appears slightly damaged by running through silt and sand, can significantly reduce performance efficiency and fuel economy, and can more severely damage itself through cavitation erosion emanating from the blades' irregular leading edges. In one test with a damaged propeller, top speed fell more than 13%. Acceleration was off over 37%. Optimum cruise miles slowed 21%. Worse yet, damage usually is not done to each blade uniformly and, therefore, the damage can set up imbalance vibrations that can cause fatigue damage to other parts of the engine or drive. If you boat in shallow or rocky waters, you will want to check your propeller more frequently for possible damage. Stingray Powerboats


To have a hole in prop you must be experiencing cavitation. Heres some words on cavitation:

As a shape passes through water at an increasing speed, the pressure that holds the water to the sides and back of the shape is lowered. Depending upon the water temperature, when the pressure reaches a sufficiently low level, boiling (i.e., the formation of water vapor) will begin. The collapsing action, or implosion, of the bubbles releases energy that chips away at the blades, causing a "cavitation burn" or erosion of the metal.
The initial cause of the low pressure may be nicks in the leading edge, too much cup, sharp leading edge corners, improper polishing, or, sometimes, poor blade design. Massive cavitation by itself is rare, and it usually is caused by a propeller that is severely bent or has had its blade tips broken off resulting in a propeller that is far too small in diameter for the engine. StingrayPowerboats


Finally, here's a couple of videos showing a propellor repair shop repairing stainless steel props including a couple of duo props. You'll see your props are not bad by comparison and are certainly repairable.

http://www.youtube.com/watch?v=eq9PwAgDroQ

http://www.youtube.com/watch?v=sNvgSaRWnkA


Hope all this helps your understanding of props. As Melida says, you may need to get your props repitched and cleaned. To prevent further cavitation damage you certainly need to have the chip and that hole repaired.

Regards


Terry

 

[Lord Farringdon]

View attachment 18925View attachment 18924

Done as you guys advised over the weekend. The port engine definitely shown an improvement. Temperature hangs around 180 degree. This is the engine I could feel the "vacuum" when I open the lid. There is no much difference on the other engine. I don't feel any "vacuum" even I swapped over the lids. I don spot any cracks anywhere. The water seems go down quicker than the port side when I filled the cup with fresh water. I have used the hose to blow down the engine side of the sea water cooling (not the impler side) and it seems flowing quite smooth. But the temperature still stays at around 200 at crusing (2500 ~ 3000 rpm). I didn't try any WOT condition because of the weather.

Richard

I guess in the end, regardless of the differences in water levels, the impellors must be working in both engines or else you would be having immediate and severe overheats, like I did, not just hotter than normal running temps. You would simple cook your engine if no raw water circulation was occuring and that would happen very quickly unless you monitered your gauges closely! Fortunatley, I did and caught the overheat before it developed very far.

You have the luxury of two engines so if you wanted to you could just swap over your water pumps (two bolts and some hose clips) and see if the problem goes to the other engine. But having said that, Melida and I both keep coming back to cleaning and descaling your oil cooler and heat exchanger. Until this is done we are chasing our tails.

You need to be satisfied that your raw water cooling system right from the inlets on your drives to your exhaust elbows and everything in between (pipes, hoses, sterring and oil coolers, aftercoolers, heat exchangers etc) are all clear. The time to check all this is when you are removing heat exchangers and oil coolers.

Would you have someone do this work for you, or would you do it yourself, in which case I can help with some advice and things to watch out for?

Good luck Richard


Terry

 

[OldSkool]

Gents,
The self priming pumps are just to push the air out of the top of the pump. It must have water to help seal the pump impellers. As you know they will push a lot further than they will draw. It would seem like there should be a check valve in the suction side to hold water in the pump. I'm not up to speed on these applications however the water should not go below the pump impeller in my opinion.

Just my thought. Can a check valve be installed if you do not have one?

 

[Lord Farringdon]

It would seem like there should be a check valve in the suction side to hold water in the pump....... the water should not go below the pump impeller in my opinion........ Can a check valve be installed if you do not have one?

Hi Bill,

There is no check valve but I guess so long as you don't open the rw strainer cap, no air will enter the system and the problem doesn't occur. Of course you have to check the rw strainer at some stage (I do it prior to the first start of the day but don't bother for the rest of the day, unless I run through a large field of floating kelp or get in close to the beach and suck up some shells.

I was wondeing about rw flow alarms such as this:

http://www.marinedirect.com.au/catalogue/category158/c1978/c2009/p106818

I wonder if they act as a non-return type valve when flow ceases? That would kill two birds with one stone :lol:

Terry

 

[Lord Farringdon]

Double post. Sorry.

 

[Richard F]

Hi Guys,

I have checked the exchangers and the after coolers. They have no sign of blockage or enough dirts inside. Water seems pasing through with a hose quite freely. I still have the temp. reads 210~220 running at wot on the STB engine but no alarm (not sure if I run it any longer). No experience on the coolant expanding into the expansion tank...... just wonder..... could that just the sensor not working properly?

Richard

 

[Lord Farringdon]

I have checked the exchangers and the after coolers. They have no sign of blockage or enough dirts inside. Water seems pasing through with a hose quite freely.

Hi Richard, good to hear from you again. I hope all is going well. When you say you have checked the exchangers and after coolers what do you actually mean? Did you just take one end of the exchangers off, look at the general condition and then spray some water through them? Or, did you completely remove them from the boat and have them descaled, that is have all the crusty bits taken off the piping on both sides (raw water and coolant)? Did you remove the oil coolers and, did you also have them descaled?

The point is that water may freely flow through the piping but that doesn't mean the coolers and exchangers are transferring heat properly. The piping may not be clogged at all but it may have a thin layer of crust all over every pipe and on both sides of the pipe. This will act as an insulator and prevent heat from transferring from the coolant to the raw water or, in the case of the coolers, from the oil to the raw water. These need to be cleaned properly using a chemical descaler. If you haven't actually done this and only flushed some water through, then you haven't really addressed the potential problem. It would come as no surprise to me that you are still experiencing high engine temps.

I still have the temp. reads 210~220 running at wot on the STB engine but no alarm (not sure if I run it any longer). ......just wonder..... could that just the sensor not working properly?

If I understand the system correctly, there are two water temperature sensors on each engine. One sensor is wired to your gauge and gives you your gauge reading. That one must be working. The other is wired to your EDC and lets your computer know what temperature the engine is running at. If this sensor signals the engine is too hot then the computer will drop the rpm to protect your engine and an alarm will sound from under your dash. So, that sensor must be working as well, otherwise your computer would detect a fault and you would see flashing diagnostic lights on your activation panel. Do you know if you have a working warning horn? Do you hear it when you turn your ignition to the on position before you actually start the engine?

 

[Richard F]

Hi Terry,

Thank you for your advice. I did take the after cooler inserts out completely and cleaned out each pipe. Only I had problems in taking the exchangers out. If you remember the photos that I posted before. The two KAD 300 were packed inside the engine compartment and it's so difficult to get to anywhere and work on. I spend half of the time just to finding a space to work. I must admit that I only took one end out and checked and cleaned :smt101. Looks like what you said will not be a weekend job (for me) I have to wait till I can spare a few days to do it. Any advice or short cuts in doing them?

Richard

 

[Lord Farringdon]

Hi Richard, sorry to not get straight back to you. I seem to be awfully busy at the moment. I think you are right. You are going to need a few days to do this but even though your powerplants are tight it is a doable job with a bit of planning. No shortcuts though I am afraid, but a careful, methodical and calm approach to the job will get you there.

I am looking at the photo of your engine bay as I write this.

The first thing that strikes me is that you appear to have some room on the left of your port engine (looking forward) but I am not sure if that means you have the same amount of room on the right of your starboard engine which is where the really hard work is going to take place. I would need to see a better photo of this area.

The second thing that stands out is that the hatch strut in the centre will probably have to be removed and the hatch held up by some other means or even removed. Whatever option is taken here, extreme care must be taken to avoid the hatch falling on you. They are heavy and the results of getting hit by an out of control hatch would not be pretty.

The third thing is that you will have to be prepared to remove a lot of compnonentry in order to free up the space necessary to access the heat exchangers and the oil coolers. I would start by removing the superchargers, air intakes and filters and associated piping and the coolant resovoir tanks. All that stuff is pretty easy and you would be surprised how much room and access you suddenly have. You might also have to consider removing the after cooler box on the starboard engine in order to gain better access to the port engine exchanger.

The forth thing is that you may have to invest in some good 'reach' tools if you don't already have them. Socket extensions will be a must. Don't be frightened to stop work and go buy a tool that gives you better access before you get frustrated and throw the towel in !! You should also look at those oil change suction containers which can be used for oil or coolant removal. You wont need to remove the oil but you will need to remove coolant and it looks a little too tight in there to get at all the drain plugs. And, make sure you have good lighting. seeing properly what you are trying to gain access to makes all the difference.

I would look at erecting some form of 'scaffold' over the the two engines that you can lie on to give you better, controlled and more comfortable access. Just be sure no weight goes on those fuel pipes or any other part of the engines really.something that restes in the hatch drain gutters might do the trick. Disassemble the port engine first. That way you'll know exactly what you need to look for, and where to find it when you disassemble the starboard engine which has more difficult access.

Finally, while it may be a little tight to work on, the actual job is simply one of removing a few nuts, bolts and hose clips, pulling off the exchangers and oil coolers, having them descaled and putting them back on. There is nothing too technical about he job at all. Don't get hung up on how long it is going to take or try to get the work complete before a certain date. You will only put undue pressure on yourself. Instead, think of it in terms of "the job will take....as long as it takes to do a good job!! " When the job is finished, you will have a great sense of satisfaction, you will have learnt a whole lot more about your engines and you will have solved your overheating problem which I suggest you currently have because no previous owner has been prepared to carryout this maintenance work or pay someone to do it.

Good luck Richard and PM me if you want to talk through some of this in more detail when you are ready to move ahead on this work.

Terry

 

[stephens013]

All and all it sounds like your boat has a nasty bottom and/or props. Dose not takes much fouling material to produce the performance you are describing. Same thing happened to my boat. I was amazed how little junk on the bottom made such a significant difference in performance.