Hi all
My Vetus 27hp is only 347 hrs old and the previous owner who repowered the boat with this Vetus was fastidious with his maintenance routine. I bought the boat late January and have probably done 70hrs max of the total 347.
In doing the 100-hour service (a little overdue at 347 hrs...my bad), the Delphi CAV 296 fuel filter was found to be in a shocking state. Picture attached.
Of course, I have replaced the filthy filter, however, I am unsure what to do next.
I have had various pieces of advice:
a) from the 100l capacity tank, drain the remaining 70 litres of diesel, clean the tank (????) and start afresh.
b) top the tank up to near capacity to prevent future condensation and algal growth
or;
c) simply add diesel fuel additive.
Not being mechanically inclined and, bearing in mind the engine's low hours and the previous owner's high quality of maintenance, I'm just concerned there may be a more serious underlying problem.
Ideas? Thanks in advance.

Your issue is in the fuel system, not really to do with motor hours. The fuel tank and lines are contaminated with algae - rather badly by the look of it... What you choose to do depends on a number of factors. Your tank will have this sludge on the bottom and possibly sides, so it needs cleaning as well as replacing or cleaning (polishing) your fuel. This action depends on boat and tank - whether your tank has an inspection/cleaning point (removable section on the top) or whether it's a relatively small tank and easily removed for cleaning. Also good to replace fuel lines, then fill with new fuel, add bactericide and keep your tank near full in future. Depending on where your boat is located, you might be able to get the fuel and tank cleaned professionally, or you may prefer to do it yourself to learn about the fuel system. It's all do-able, but the last thing you need is for rough seas to stir the gunk up and block your full system when you most need your motor!
Wavesong
The good thing is that you have discovered a problem before it got really bad.
The bad thing is that you now have to deal with it.
Bushdog's sound advice (and more to come ) will see you through this (mess).
It is all part of the game.
Grin put on your rubber gloves and bear it
All the best
gary
PS welcome aboard.
At least it is a cavfilter
go to repco buy a box of them
add the additive of your choice
alfoc was the best but I have used diesel power for years and wait until it is on special at supercheap
then change the filter at after one hour then after two hours etc
while that is a pain will be easier then removing the tank etc
then keep the tank topped up
only real worry with the pic is there must have been a good deal of moisture in the tank
if you are removing the tank put a sump cock in it
Hi, been there done that, I use fuel doctor at the rate of 1 ml per litre, I cleaned the crap out of the bottom of the tanks as best as possible and changed the filters until no more crap was evident on them. Do check the ? ring around the filler cap, a damaged one is usually the source of water in the tank. You found the problem at the right time.
At least it is a cavfilter
go to repco buy a box of them
add the additive of your choice
alfoc was the best but I have used diesel power for years and wait until it is on special at supercheap
then change the filter at after one hour then after two hours etc
while that is a pain will be easier then removing the tank etc
then keep the tank topped up
only real worry with the pic is there must have been a good deal of moisture in the tank
if you are removing the tank put a sump cock in it
Hi, been there done that, I use fuel doctor at the rate of 1 ml per litre, I cleaned the crap out of the bottom of the tanks as best as possible and changed the filters until no more crap was evident on them. Do check the ? ring around the filler cap, a damaged one is usually the source of water in the tank. You found the problem at the right time.
Thanks gentlemen.
If I decide to go this way, I'm thinking a certain amount of sludge will remain in the very bottom (and on the sides?) of the tank? So, in rough conditions, will that sludge churn around causing the same old problem?
Draining and cleaning the tank plus replacing the fuel lines and deck filler then refilling to the brim sounds like the gold standard treatment? All I'm seeing is dollar signs.
Ballpark figure, how many B.O.A.Ts might I be looking at??
Although my mechanical skills are BASIC, I'm not afraid of getting filthy and having a go myself. I'm keen to learn.
Thoughts?
Ballpark figure, how many B.O.A.Ts might I be looking at??
Although my mechanical skills are BASIC, I'm not afraid of getting filthy and having a go myself. I'm keen to learn.
Thoughts?
How long is a piece of string!!
Some boats the fuel tank can be removed easily, others not so easy. To remove my tanks it would be a very major operation!!
Where are you? - someone from here could be very close & call in & have a look for you.
What type of boat?? - Where is the tank?? - might be someone here with the same & give you ideas.
I also use Fuel Doctor.
Shouldn't run into even 1 Boat$ if it's easy to get to!!
I run a very basic fuel polishing system with the pick up in the lowest point to pick up any crud - very easy to install as well.
Best of luck. :)
Unless you are in nasty waves all the time the above will work pretty quickly
also Vetus have an electric fuel pump so easy to bleed quickly
just tape the right spanner for the breather near it in the engine box
yours seems more a water problem than real bad algal infestation
ie no big black bits
Your filter looks like my truck filter did after I left it sitting outdoors unused for a couple of years with the tanks 3/4 full and no fuel additives in the diesel.
I emptied the tanks as best I could into 50L plastic storage bins and was going to dump the old fuel at the local tip but had no containers to take it there for disposal. So rather then dump it I decided to try and use it up. I ended up filtering the dirty diesel trough some old work socks then again through some old pillow case to get rid of the larger algae and lumps of bacteria then added some Chemtech Diesel Power Fuel Additive I bought from Repco at double the recommended dose and poured it back in the tanks. I fitted a new filter and ran the truck for another 40km after the empty fuel light came on so I only had about 5L of the old diesel left in the tanks before filling up to the brim with fresh diesel and adding Chemtech , again at double the recommended dose and changed to a new filter. After doing the same thing a couple more times I couldn't find any more crap in the filter and now that I keep the tanks filled up and use Chemtech with each refill I have no issues and filter is clean.
The whole exercise cost me about 30 bucks for 1L of Chemtech and about 30 bucks for 6 cheapie ebay filters to change between each refueling so if you can change a filter yourself or empty a fuel tank you won't need to BOAT . Just run the tank as close to empty as possible , change filters with each refill and add Chemtech until all sludge has gone.
www.repco.com.au/en/oils-fluids/additives/fuel-additives/chemtech-diesel-power-fuel-additive-1l/p/A7870493
www.ebay.com.au/itm/FC1702-6x-Fuel-Filters-Dodge-International-IH-Truck-w-Perkins-Engine-rpl-CAV-296/273811443889
Ballpark figure, how many B.O.A.Ts might I be looking at??
Although my mechanical skills are BASIC, I'm not afraid of getting filthy and having a go myself. I'm keen to learn.
Thoughts?
How long is a piece of string!!
Some boats the fuel tank can be removed easily, others not so easy. To remove my tanks it would be a very major operation!!
Where are you? - someone from here could be very close & call in & have a look for you.
What type of boat?? - Where is the tank?? - might be someone here with the same & give you ideas.
I also use Fuel Doctor.
Shouldn't run into even 1 Boat$ if it's easy to get to!!
I run a very basic fuel polishing system with the pick up in the lowest point to pick up any crud - very easy to install as well.
Best of luck. :)
Hi, I opted to put together a high volume basic polishing system using a fuel transfer pump as used to refuel earthmoving equipment (complete with servo type nozzle) so that the returning fuel would stir up the remaining contents, and a high volume water separator/filter on the suction side. Probably ended up costing four to five hundred dollars but money well spent and I use it a couple of times a year as preventative maintenance. The o ring on the filler is available wherever o rings are sold and cheap, just take an old one with you and buy two or three. If you don't have direct access to the tank then fit or have fitted a standard fuel filler fitting directly above the lowest part of the tank and draw the fuel from there. If this is too difficult then perhaps a local may be able to point you in the direction of someone that can provide this service for you. For what it is worth, Fuel Doctor is a Queensland based business that I believe also provides a polishing service.
Ballpark figure, how many B.O.A.Ts might I be looking at??
Will start with an "if".
If you have an access hatch on the tank which will allow you to get your arm in and clean. $300.
Do you have a hatch on the tank?
1. 4 x 18 litre containers to take the spoiled fuel. =
2. rags and correct detergent/solvent to clean tank internal ( some suggestions are bleach, vinegar home brew sterilizer) =
3. 6 X fuel filters =
4. fuel treatment (of your choice) =
5. 100 litres of fuel.
Process.
Drain tank.
Remove hatch and clean tank. Use a dust pan , paint scraper and rags. Clean with correct detergent or solvent.
Remove and clean cock at tank outlet. , Replace.
Remove fuel lines to filter, Blow out with compressed air and flush with detergent. Replace
Remove fuel lines from filter to pump, Blow out with compressed air and flush with detergent. Replace
Check hatch gasket. replace if in doubt. Refit hatch .
Fit new filter.
Fill tank with new fuel and bleed system. Add treatment.
Find where the water leaked in and repair.
You can follow Harbs advice and clean and add the old fuel 10 litres at a time or so.
You could also do as Uncle Bob has suggested and polish the fuel, but that type of system costs extra and involves extra work,
Or you could just dispose of the old fuel and call it a lesson.
Check Fueldoctor for cleaning proccess
www.fueldoctors.com.au
Gary
As said before , less than a grand depending , same prob . I got rid of tank , put a new smaller poly tank and lines in . Lots of dirty work ,little money . Cheap Jerry cans for old fuel and went online and found council chemical cleanup , drive thru , they take your stuff out of boot , drive off. Used a Jerry can for a while as temporary fuel tank so could still use boat . Good way to learn your boat .
Assuming there are no inspection hatches, another interim option is to rock the boat as much as you can to stir things up and just drain and rinse the tank a few times. You will need several jerry cans and it will give you a feel for how much crud is in the tank. This would be useful if there is a large amount of water there.
A