Mainship Pilot 34 Fuel Tank Pick-up - Screens ?

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TomF

Member
Joined
Apr 16, 2021
Messages
21
Vessel Name
Liberty
Vessel Make
Mainship Pilot 34 - 2003
Dreaded water in the tank. I have a 2003 MP - 34 with a single 250 gallon tank and twin Yanmar 4lha-stp. I believe I have water in the tank as I have microbial growth (green slime). Are there screens in the pick-up tubes? My port engine gets bogged down and when I blow out the line she is good for a month or so. I am using Biobor JF fuel additives, are there any others to consider. My thinking is to run the tank nearly dry and then suction the remaining fuel from the port/stb fuel pick-up lines and then snake a line into the tank and pump out remaining fuel/water/slime that sits in the "V" in the center of the tank. If there are screens in the fuel pick-ups this will not work - thus the question.

Any suggestions or expierience with the remedy ?
 
When the algae dies from treatment it becomes sediment and can clog whatever. What's happening with your fuel filters? Why only the Port engine?

Regardless given the age and conditions a fuel cleaning service is probably a good investment. I had this done on my olde MSI and the process was very thorough and not terribly expensive.

The crud is in there, its got to come out one way or another, get it out on your terms

:socool:
 
Thanks for the reply. Agreed the crud and suspected water needs to go. I am up north and there are not many polishing contractors. My concern is that fuel polishing will not remove the suspected crud that lives in the pocket at the centerline of the tank. My 250 gallon tank has a flat bottom with a \_/ pocket located at the centerline of the tank over the keel. Will the fuel polishing be able to stir up that area and remove the crud ? This concern has me considering draining my tank and entering a suction line (pump) into both the port and stb fuel pick up locations to get the water and crud out.
 
Without knowing your boat the pocket you describe has me thinking, what is its purpose, can you put in a drain valve after draining the tank? A "sump" with drain valve is a good way to remove crud.
 
The service I used returned the fuel after polishing through a small flexible tube with a jet nozzle on the end. It swished around inside the tank like crazy making a hell of a racket and :stirring the pot" pretty well. If you can find one, these guys are typically pretty good about different configurations, and stirring up the sludge is part of the program. You not only have the usual crud, but all the dead algae as well.
He had a piece of clear hose on the intake and return, to keep track of how clean the fuel was coming out and going back

Good Luck :thumb:
 
Thanks for the replies.

The "trough" in the tank is to allow sediment to collect. The fuel feed lines are located at the level plane above the \_/.

I assume in the 250 gallon single tank their are baffles that will prevent the neet "jet spray" that Keysdisease described.

Still thinking about how best to clean my tank, polish vs. drain.

Any experiences from MS owners with the single 250 gallon tank appreciated.
 
TomF, at first, I got the impression that you have a standpipe fuel delivery system through the top of the tank and then probably confused myself about that reading a later post. There is another thread running today where I passionately argue against standpipe systems. To me they are just a situation like your waiting to happen rather than continuous clearing out of any bottom debris. In another vein, there are kits available for installing inspection and cleaning ports into diesel tanks.
 
I recently had my fuel polished. Cost was $1200 for both tanks. After doing this and changing the filters it resolved our issue with frequent clogged filters. Tech said that the port tank had growth and water thus causing the problem.
 
Lollygag1 - when you say "both tanks" do you actually have two seperate tanks , or is your MS Pilot 34 like mine with one 250 gallon tank that you can fuel from the port and starboard side inlets ? Did your tech polish in the water, or did they require you to haul your boat ? Glad to hear you got "cleaned up" . We are running to Block next week and may stop into RI for some cleaning ourselves.
 
Tom we are a single engine w 2 tanks. The polishing took place in the water only took a few hours. The firm I had came to the marine and did this.
 
I just put a nylon tube into one of my pickups, and pulled a different one, including the standpipe out of the other tank. Neither had screens on them. I have an 05 400, so different boat but I would guess your tanks are built very similar to mine.
 
Doug, thank you. This answers one of my questions regarding screens. I am considering doing the same procedure that you completed. Can you tell me the GPM capacity of the pump you used. I have read that you need a minimum of a 80 GPM pump to stir up the microbe slime and water for proper filtering.
 
Doug, thank you. This answers one of my questions regarding screens. I am considering doing the same procedure that you completed. Can you tell me the GPM capacity of the pump you used. I have read that you need a minimum of a 80 GPM pump to stir up the microbe slime and water for proper filtering.

Not sure on pump capacity but it is very high. I used micronix fuel service out of Stuart. His pump is on his truck. He pulled 55 gallons of fuel out of my tank in 10 minutes through a 3/8” tube.
 
I purchased a 16 GPM diesel transfer pump for $100 on Amazon. My buddy is going to lend me a high capacity racor filter set-up with a bunch of filters for change-out. I am going to self polish my fuel by using the port and starboard fuel pick-up tubes. I plan to polish the fuel in the next couple of weeks. I will report back on results once complete.

Thanks all for providing information and insight.
 
I have the same boat/engine set as you do.

No screens in the pick ups.

I too had one motor big down on me under way a few years ago. A member of my club (who has an old Hatteras with twin 8v71’s) turned me into this fuel additive.

It’s not cheap, but it works. I use it every fill up now.

Keeps the sludge at bay.
https://www.defender.com/product3.jsp?path=-1&id=3862149
 
I purchased a 16 GPM diesel transfer pump for $100 on Amazon. My buddy is going to lend me a high capacity racor filter set-up with a bunch of filters for change-out. I am going to self polish my fuel by using the port and starboard fuel pick-up tubes. I plan to polish the fuel in the next couple of weeks. I will report back on results once complete.

Thanks all for providing information and insight.

The fuel pickup tubes probably won’t flow enough fuel to do a really good job of polishing the fuel. If you have access plates in the top I would pull one and get a larger pickup tube in the tank so you can get more flow. You want to get the crap suspended so it can be drawn out and filtered out.
 
I have a AXI TK-240 tank cleaner fuel polishing unit I used it once to clean my port tank on my North Pacific 43 it has extra filters I was able to get the water and slug out of the tank leaving the diesel in the tank and the boat in the water I was told it would cost me between 1000.00 and $1500.00 to have cleaned I purchased AXI for $1200 I would consider selling for $1000 + shipping if interested or you may want to look in to other options or model
 
Remove all fuel. Cut an access panel in the top of the tank. You will likely find a few gallons of biomass in the bottom. Remove and clean tank. Cover access hole. Polish fuel. Always store tank full over the lay up period to reduce condensation.

I had this work done in Mexico on my two 300 gallon black iron tanks some years ago. Each tank had 5 gallons of reddish goo inside. At first we thought the tanks had rusted. They had to remove and later reattach the baffels inside for access. They literally sent a small Mexican inside the tanks to clean them. The fuel was literally 60% water!
 
]Epilogue: I now have smooth running engines. Here is what I learned and cleaned.
1. The main issue was a plugged port Racor 500 MA fuel filter. The microbe sludge clogged the venturi tube where the fuel enters the filter and lodged the check ball not allowing the the centrifuge to spin off solids and water, plugging the filter and causing vacuum issues and port engine RPM surges. Removed and cleaned.

2. Built a polishing rig with a Racor 900M filter and 16 GPM pump. Circulated and filtered fuel using the port and starboard fuel pick up pipes. Not optimal as mentioned above, but was able to remove remaining water from tank. Ran tank down to about 60 gallons and then polished. Removed about a pint of water from fuel. Not a lot of "green sludge" came out, but hoping with not water in the tank can kill remaining microbes with treatment.

Appreciate the comments along the way and hope my journey can help others.
 

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