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For and against Water separator/Fuel filter


icefisherman

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According to a Merc bulletin there are many things to watch for with alcohol in fuels. I dug up a bulletin from Oct 06 and it states do not use fuels containing more than 10% alcohol or damage to fuel systems may occur.

Unlike automotive systems boat fuel systems are vented to atmosphere. Alcohol absorbs water like a sponge. So long periods of exposure to atmospheric conditions will eventually lead to phase separation. The alcohol and water separated out forms an acid that can corrode fuel system parts. This can create a lean/fuel air ratio and damage engines.

After 1996 mercs were built to withstand 10% alcohol but no more than that.

Another thing to watch out for is fuel tanks made from fiberglass. Alcohol can deteriorate fuel tanks made before 1991 and carry the dissolved debris into the fuel system.

Additionally Merc does not want additional filters or separators added to their systems that may cause further restrictions of fuel supply which may cause lean mixtures. Other manufacturers are recommending additional water separators be added.

I'm finding this very interesting research and I will add to this as I find out more info.

 

Hmmm...I know you are looking into this further, but from what I gather here, 1997 mercs and newer can run up to 10% ethanol. So what does this mean for my 1983? Your other post says they also say not to use those separators...is that just on those newer models? Hmmm....I'll keep watching this thread. Thanks Bernie!

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I just called around to 3 marine mechanics in my area, they ALL told me not to run a filter if I pre-mix my fuel/oil. Good chance of burning up the engine. One guy told me that sometimes the oil will get separated in the filter as well as the water....??

 

I'm just gonna run mine like I always do, my gas doesn't last long enough to go bad. I'd do something different if my gas was sitting around for a while though.........

 

Sinker

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What owners will need to watch out for or possibly replace are fuel lines. Older fuel lines were not designed for alcohol and may deteriorate. The deteriorated pieces may get into carburators. Also they may develop leaks because the alcohol could soak through.

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I just called around to 3 marine mechanics in my area, they ALL told me not to run a filter if I pre-mix my fuel/oil. Good chance of burning up the engine. One guy told me that sometimes the oil will get separated in the filter as well as the water....??

 

I'm just gonna run mine like I always do, my gas doesn't last long enough to go bad. I'd do something different if my gas was sitting around for a while though.........

 

Sinker

 

 

Sinker,

two things pop into my mind after reading your comments.

1) My motor is fuel inhection so since it is new and my mechanic hasn't worked on it yet maybe he is telling me not to install a filter because he is assuming it is "pre-mix" and it is not as oil gets mixed with gas inside the engine not in the tank.

2) The more I think about this issue I wonder - maybe one of the resons (among others) for seizing my 60HP 2 Stroke Johnson last September is NOT using water separator.... :wallbash: It was "premix" motor.

 

Cheers,

Ice Fisherman

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I think I have narrowed it down. I have an '83 two stoke so I do need a separator. I ran it last year for about 200 hours so I don't need a separator. :dunno:

 

LOL. I hear you Cranks.

 

I would like to be able to copy and paste the entire bulletin on here but cannot due to copy write but if I read it thoroughly and understand it the same way I will be able to possibly pass on the finer points.

 

icefisherman. The most common reason for engine failure is lack of or poor lubrication or lean fuel mixture.

Edited by Bernie
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A couple more notes

Alcohol can increase the possibility of vapor lock. This can make it difficult for your fuel pump to pick up and continue to supply fuel. Fuel under pressure reduces vapor lock.

 

Also in an Evinrude bulletin they are saying a test kit is available from Briggs & Stratton suppliers for checking alcohol content in fuel. Part # 100023 and is $5.45 US. It is available on-line at briggsandstratton.com

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Do not use high octane fuel in your pre mix if you don't plan to use the

hole tank that day.

High octane fuel has large amounts of detergents in it that will back down the oil.

 

Most diaphragm fuel pumps do not have enough CFM's to pull the fuel through a

water separator. making the engine run lean.

 

Older engines fuel lines should changed to ethanol rated lines.

 

Gas has a shell life of about 6 weeks.

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I don't use a seperator on anything i currently own, but it can't hurt to put one on.

The one thing i do do is add isopropal based gas line antifrezze to everything every couple of tanks as iso will bond with water and remove it from the system summer or winter, for storage can't really beat yamaha fuel stabilzer it's 100% hydrocarbon based.

on the other hand not sure how much iso alcohol will effect a 2-strokers a/f ratio causing a lean issue.

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More info on this subject....just got home after stopping at a Shell gas station on Hwy 401 and Trafalgar Rd. - the GOOD news is they don't sell ANY gas that has ethanol....so 87, 89, 91 ALL are ethanol FREE!!!

Super news to me as this gas station often is on my way to the fishing spots on lake Erie and Lake O. so I'll start filling up there all the time. Manager was there and said no plans to go on ethanol any time soon. This makes me thing marines must have access to same ethanol free gas as well.

 

News number 2 for the day:

 

Spoke to a good marine today in Oakville....the chief mechanic told me no problems with water separator/fuel filter from Racor and my two motors. But he said there is a trick to it to ensure problem free flow of fuel to either motor.

The order is like this:

 

Fuel tank.....fuel hose.....primer ball.....fuel filter/water separator.....either motor....

 

In other words....the primer ball MUST be BEFORE the water separator...this way squizing the ball few times fills up the fuel filter with gas and starting the motors and running them after that is no problem at all. He sais he has installed many such filters and had never had problems with starving the motor. He was actually trying to sell me a Mec filter for about $50...but I went and bought the Racor today...also got spare replacement element....so should be all set now....the Racor filter and the ethanol free Shell gas should resolve this issue once and for ever.

 

Cheers,

Ice Fisherman

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