Yanmar RPM Woes

[S/V Illusion]

Originally Posted by PaulM

I removed the primary filter and it was black with bugs along with the water separator. I replaced the primary with a 2 um, which kind of makes the secondary useless. I was going to use 10 um, but forgot the wrench I couldn't open the canister for the secondary. The vent line was clear and the pick-up was free of any resistance in or out. The engine ran well. The question now is, the best way to treat the tank?

Paul

Paul
You are correct that putting a 2 micron is as the primary makes the secondary useless. This is precisely why engine mfgs recommend a larger primary - Yanmar recommends a 30 micron primary.
You can treat the tank contents by running the fuel through a filter but that cleans only the fuel. The bugs and crud reside on the walls and bottom of the tank only to re-suspend upon agitation.
What you should do is clean the tank itself.

[Tropic Cat]

I use inexpensive 100 micron primary filters (2 engines). Every now and then I do check the secondary filters, and they always looks fine. I did change them 2 years ago just on principle.

[Vasco]

Paul,

If you can remove the tank that's the best approach. I sucked the fuel out of mine and took it to a rad shop where they cleaned it. If you can't remove it look up "fuel polishing" in your area. They will come down and polish the fuel, running it through a few times and cleaning all the crud out of the tank. Nothing worse than crud in the tank. I put up with it for a year and every time I bounced around a bit when I used the engine it would sputter etc. Finally cleaned it and have had no problems since.

[mastconfusion]

Paul I recommend that you use bio bore to treat the bugs that may be living in your tank and some BG 227d as extra lubricant and detergent for ultra low sulfur fuel so you don’t end up with any fuel related problems from here on out. Jeff

[PaulM]

Thanks to all. As I expected. Cleaning the tank is the long term plan. Will be a big job as the tank is under the cockpit. For now, I will use the biocide and lubricant as Jeff suggested. And buy some extra filters on have on hand to deal with the dead ones.

Paul

[Inlet Marine Services]

The best way is to have the tank cleaned, you can use products such as BioBor Jr the kills the bugs and use a all season addiative which enhances the ability to clean. Keep using the two micron and buy a few extra, I would even put a vacuum gauge on your racor, it lets you know when you are plugging up before you do. As the products kill the stuff you plug up filters.

[PaulM]

I like the idea of a vacuum gauge. I'm guessing it would go on the outlet to the rancor filter so that when it started to clog there would be a vacuum from the fuel being pulled to the lift pump. What sort of range would I need?

Paul

[keyspc]

dump some bio-bor in the tank and make sure you have more than a few filters on board.
also, never ever take the screen off the fuel intake! remove the fuel line and blow in it. you should be able to do that with out to much strain. if its impossible to do you've got a clog and your itti bitty lift pump is working way to hard.

FIX: remove strainer and clean and replace. get a electric pump and hook it up to filter and bang hose around bottom of tank -return goes back in fill.
I like to have two racors and a pump and valve asembly so i can by pass a filter or clean out tank without hassel

[Inlet Marine Services]

depending on the racor filter head is where you would put the vacuum gauge. Racor makes a kit and their vacuum gauge is color graphed, simple look to see whats going on. What racor filter do you use?

[bill good]

would not put biobor in by "dumping it in" as it will cause a lump of dead bug to collect in one place. I think I put 2ccs/litre in as the fuel is added. The corect amount is on the tin.