Unburnt diesel

D

Dover Escape

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Hi
I have a sealine S23 with a KAD32

Starts on the button bit of smoke on start up if not used for a while then clears.
When I throttle up it leaves a trail of what I think is unspent diesel in the water. It is a grey sooty bubbly mixture at the rear of the wake and I am sure VP would not have been happy with this.
Bottom clean and props are new this season and are the correct size.
Injectors refurbished Turbo reconditioned and speed sensor changed all filters changed including crank case breatherr. belts changed so not sure what else it could be but its eating me up !
Not losing oil and I get a max of about 24 knots when others say they get nearer 30
Supercharger kicks in and out ok and guess that turbo is ok but having never heard another one I am not sure.
I love the boat but am about 3k down and engineer tells me that it's just an old boat 2003 but everyone else does not have the problem and seems to get better performance so any views woukd be very welcome .
Thanks
Steve
 
May carbon deposit if it looks like soot lying on top of the water surface ... which could have been building up if engine have not been running at operating temperature for a while... (e.g. on canals for prolonged periods)

Sounds like you have done the expensive things such as injectors and turbo ... what a bout the valves / clearances etc. (intake and exhaust) ??

Moist of all KIS !! .. what kind of RPM are you getting at WOT under load ? .. Think you should be getting around 3800 RPM on that engine if I am not too wrong ...
 
Thanks for the reply. It has been on the sea now for a couple of years but probably only gets out about 6 times a year for an hour or so but always at speed. There was an issue with dirty fuel in Dover last year so they will do a tank polish for £20 so that probably makes sense but I have had a few tankfuls since the problem so doubt it is still suffering from that.
I also have put some injector cleaner in so dont know how long that usually takes to make a difference.
The max RPM is usually about 3400 so always been a bit low but not also 100% i trust the rev-counter as I had to change it last year so probably needs re-calibrating.
I have never checked the valve clearances so would be very interested to know how to do that and also someone once mentioned that the fuel pump which is an expensive part could be an issue so what do you reckon on that too.
Should there be any trace of this with an old engine as wonder if I am just going overboard so to speak !

Thanks
Steve
 
Keep It Simple = KIS .
Plenty of utube vids on valve lash .
You need to be 1/2 handy with spanners and ideally done it a few times in your youth tuning up cars .
Its particularly important with diesels due to higher compression, higher cylinder pressure s the last few mm of opening / closing can make a huge difference to the power .

I understand there may be access issues with some KAD series in terms of having to clear away the fuel pipe s ? Not sure if that applies to your 32 ?? Someone will be along soon to clear up that point .

They ( valve gap s ) tend to wear bigger so the opening time’s are shorter .
Also they tend to snap more shut and open as the rocker slams on them .....suggestions in some circles this leads to premature stem failure , and adverse lateral movement which leads to premature valve guide wear = smoke and burning oil as it leaks down the now poorly fitting stem .

Theres everything to gain following the manufactures valve clearance intervals .AKA as valve lash adjustment and tappets adjustment.

For me it’s every 400 hrs , .
Noticable smoother running and power increase as well as quieter at tick over straight after .
 
(y)
Yup ... KIS = Keep It Simple

Basically before you start digging into complex (and often expensive) things... look out for the simpler things ..

1) Fuel (Tank uptake gauze, stop valves through to filters)
2) Air (Does the engine get enough .. ie filter and intakes clear
3) Clean hull and drive system and no damage on propeller(s)
4) Do you get WOT (OP sound like 400 RPM low) ... but if rev counter may be off-kilter, it may be more than 400 RPM, which could be anything from over-propped to more issues
5) Clogged up exhaust bend (seen that on many VP's) ... easy to check in principle ... if you can get access to it and if it is above water level ... if clogged up, the engine will be restricted...

1, 2, 3, & 5 are the first simple things I'd check before even contemplating the more expensive ones ... and valve clearances which Portofino have talked about is one of the next ones I'd do ...
 
Good advice so very much appreciated. I have only just had it out of the water and bought new Duoprops from Keypart (A4'S) so that is one job to take off the list !

I have only ever changed the 2 fuel filters and not looked at anything else and do not know what the gauze or stop valves are.

My old Dad used to be a mobile motor engine tuner back in the day and is now 83 but I am sure can rack his brains and still has an old set of feeler gauges somewhere so that sounds like a very sensible thing to do initially and If I buy a cheap strobe light we can also check the RPM. The clearances have never been looked at.

I will then report back to you all.

I have a love hate relationship with the boat as I know that it is not quite right.

Many Thanks

Steve
 
A4's appear to be the right size .... S23 duoprops

At the pick-up point in the fuel tank there will be a gauze or a sieve, to prevent potential larger debris into the fuel system .. if that is clogged, the engine will not get enough fuel and hence lack-luster performance. However as you are experiencing soot (black smoke) which is an indication of more fuel than you can burn, then you do not have a fuel restriction...

In addition to the valve clearances ... actually before that, I would have tried to check the exhaust elbow / riser (where exhaust meet cooling water)... just after the turbocharger ... should be relatively easy to check ... and take much less time than doing valve clearances ... if it is above water level ...
 
personally I'd add a boost pressure check to the scenario. Worn turbo's would account for a lot of your woes
 
Dover Escape said:
Good advice so very much appreciated. I have only just had it out of the water and bought new Duoprops from Keypart (A4'S) so that is one job to take off the list !

I have only ever changed the 2 fuel filters and not looked at anything else and do not know what the gauze or stop valves are.

My old Dad used to be a mobile motor engine tuner back in the day and is now 83 but I am sure can rack his brains and still has an old set of feeler gauges somewhere so that sounds like a very sensible thing to do initially and If I buy a cheap strobe light we can also check the RPM. The clearances have never been looked at.

I will then report back to you all.

I have a love hate relationship with the boat as I know that it is not quite right.

Many Thanks

Steve
Click to expand...
How did you decide prop size?

if you just replaced with what were on and they were wrong etc
boats get heavier as they get older so perhaps take everything off that you can including water and test again
there are three problems in lack of speed weight weight and weight
 
Yes I could not identify what the old ones were but they were at lease 0.5mm smaller on each blade and were pretty thin and advice was to put on the recommended ones for fear of introducing another problem however I do hear what you say and amazing how much weight you put on it so I will take out the double mattress that a PO had made who was more interested in mattress use than speed. Enough said !!

I have ordered a new air filter today and the rocker gaskets and the old chap has found his feeler gauges so we are good to take on the job.
 
The gaskets arrived today and not too costly and I also bought a new air filter but can you give me a quick idiots guide to how I can actually check that exhaust elbow the boat is in the water so can it be checked by hand etc and what would it be that is blocking it etc . Do I have to remove much to get at it.

Many Thanks and together we will best this !!!
Steve
 
Not sure about the Sealine 23 and access ... but the KAD 32 elbow looks something like this ...
51HACeLKsYL._SR600%2C315_PIWhiteStrip%2CBottomLeft%2C0%2C35_SCLZZZZZZZ_.jpg
and is the piece connected to the exhaust side of the turbocharger...

A buildup of rust where the hot exhaust meet the raw cooling water is what the blockage may be...
RiserMerc.JPG
... and I've seen water blockage and also exhaust gas blockages... simple and relatively affordable to replace (new elbow...).

Don't ask me how to remove it from a S23, but before you consider it... please verify that it's lower part is above sea level ... and suspect it may not be immediately accessible as it is at the rear of the engine...on Stbd side I believe....
 
Thank you
I have located the part and as you say a bit of a sod to get to but should be doable it's right at the top left of the engine well above the water line so I should not sink.
I had a look at what was a new air filter only a few months ago and it is pretty black so have a new one of those too.
I will report back when tappets have been done and elbow inspected.
Many Thanks
Steve
 
Had new duoprops fitted last month so all good there and bottom is clean with 3 coats of micron 350.

Went out again on Friday with a new air filter was doing max revs of 2500 and a top speed of 22 knots but rev counter may be a bit out.
I now have the new rocker cover gaskets and have located the elbow so that's my next job and will report back.
Thanks
Steve
 
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