Should I add a filter/water separator?

[el_cheapo]

I have a 1980, 85 HP johnson outboard, didn't get out much last year and at the start of this season had trouble with bad gas, everything's good now.

I've started using Marine Stabil which claims to treat ethanol, I can't see that there's any filter in the cowl of this motor (other than really coarse built into the fuel pump).

Due to my splash wells design I don't really have a great place to mount one, a 12 gallon tank just kind of wedges under there and the battery sticks out some as well. I suppose it's went 43 years with no filter maybe there's not an urgent need to add one now. If I could find one compact enough I may be able to mount it directly to the inside of my transom which would be nice I don't want to be snagging line on it inside the boat.

 

[flatheadsteve]

Do you ever run fuel with ethanol in it? Ethanol attracts moisture

 

[LDUBS]

It sure sounds like a good idea to me, but for the same reason you give, I don't us a water separator on my current boat. Didn't use one on my previous boats either. Like I said I think it is a good thing but I'm not losing any sleep over going without.

It is not practical for me to obtain non ethanol gaso. I religiously use Honda's version of Stabil (I think it is Stabil with Honda's name on the bottle). My Honda outboard has a couple of fuel filters under the hood, one on the low pressure side and one on the high pressure side. I don't think either would act as a water separator.

I do use the boat year round so hopefully, with the fuel stabilizer, I'm cycling the gasoline enough to avoid issues.

 

[alpha550]

Myself It was definitely worth the time and space to put a fuel/water separator on my outboards. I didn't have anymore problems with gummed up carbs after installing them. I still used Stabil and Sea Foam in my gas.

 

[thill]

Put a Fram PH2 or PH3 inline filter on your fuel line right in front of the motor. They are cheap and do a good job.

 

[jethro]

My Sylvan has a 40 gallon, in-floor gas tank, I use it in the ocean quite a bit and in all conditions and I have never seen a need for a fuel/water separator. If my boat lived on a dock or a mooring I would likely install one, but for a trailer boat they really aren't necessary if you follow good practices. I use the best fuel I can buy (premium and when possible, non-ethanol) and I always use Startron in every tank of fuel. I've never had a problem with gummed up carbs or fuel lines or poor running conditions and I don't believe I've ever had water in my fuel. Don't buy fuel at questionable places and don't buy super premium where those tanks may not get emptied much.

 

[el_cheapo]

Unfortunately I do mostly purchase ethanol gas, unless I'm going to lakes that are an hour + away I don't have access to ethanol free, in practice I purchase gas with ethanol 99 percent of the time and probably run through 2 12 gallon tanks a years (I do a lot of electric trolling).

I'd say finding parts, and the right person to rebuild the carb is only getting harder so I'm going to add one.

Seems like there's no problem pushing premix through these, and they appear to be the most compact separators (other than using a filter with no visible bowl). Also seems like the common thing to do is put the primer bulb, before the filter, if possible I'll mount it vertically in the left square, otherwise I'll have to take the angle on the right, maybe not as effective at water separation but appears to still function some.

Going to try a Rancor 120a, Sounds like the 10 microns can get plugged up pretty quickly I think I'll go with a 30, the jets on this carb, for an 85 hp motor are likely not as sensitive as fuel injectors or a 2 hp motor.

States it flows 15 gph, and I should pull 8.5 at WOT.

Anything I'm overlooking?

https://www.parker.com/parkerimages/Racor/10219 Rev A (120A and 120B Series).pdf

 

[JL8Jeff]

I went with the Yamaha setup since it's a little smaller. My boat sits at a dock from Apr until Oct so I thought condensation could be an issue with hot days and cool nights. When I went to change the filter the first time, there was no sign of water at all, so I'm not sure it was needed. I run OMC carbon guard in my premix gas but my boat never sits more than 5 months without being used so my gas doesn't get too old. I do add Stabil to the small amount that is left at the end of the season just in case.

 

[el_cheapo]

I went with the Yamaha setup since it's a little smaller. My boat sits at a dock from Apr until Oct so I thought condensation could be an issue with hot days and cool nights. When I went to change the filter the first time, there was no sign of water at all, so I'm not sure it was needed. I run OMC carbon guard in my premix gas but my boat never sits more than 5 months without being used so my gas doesn't get too old. I do add Stabil to the small amount that is left at the end of the season just in case.

View attachment 115368

I like that, seeing the fuel would be nice but creates another spot to leak or suck air, Looks to be roughly the same size as the 120a. (Your filter spec is 4 3/4 inch deep, the entire 120a assembly is 6.5 inches)

I'll probably go with the yamaha setup, the 120a has 5 o rings total, we're talking about ethanol fuel here.

 

[LaqueRatt]

I'm still pretty green and new to the game, but since I started putting SeaFoam in every tank and added a cheap filter, I've had no fuel issues.

 

[thill]

Again, you might want to put a Fram G3 inline to see what you come up with. If there is water, you will see it. Same with rubber dust from degraded hoses or other trash in your lines or fuel. I put them on customer's boats all the time, and they are effective. Good filtration and capacity for small tanks. And you can flush them, if they don't get too trashed. They typically last a year.



If you had a larger built-in tank, I would recommend a canister water separator, but for (2) 12 gallon tanks a year... It's pretty easy to keep that small amount of fuel fresh. Maybe move down to a 6 gallon tank, if your 12 lasts too long, or just never fill all the way up.

My aluminum boat doesn't go through much fuel either. I typically use a gallon or so per trip, so I dropped to a 6 gallon tank, and I keep a G3 inline, and I don't have any issues. Keeping the tank topped off actually helps reduce the amount of water absorbed from the air, as there is less surface area for the exchange.

But if you have your heart set on a canister water separator, just make sure every connnection is tight, inlcuding the plugs closing off the extra ports on the housing. Also, put a thin film of marine grease or Vaseline on the mating suface or O-ring, as I've had customers with fuel problems that we traced back to their water separator housing. Usually one of those two places.

 

[AlanT]

This is a very timely thread. Due to a boat reconfiguration, I'm switching from 2 of the old style 6 gallon OMC tanks to a single 12 gallon aluminum tank. The old tanks were sealed and the 12 gallon tank is vented. Even though I purchase non-ethanol gas, I was still considering a fuel water separator filter. It seems like I'm the only person using 1/4" fuel hose, which makes matching all the parts a little difficult. Some of these smaller in-line filters are not 1/4", and the Racor are over $100.

 

[el_cheapo]

This is a very timely thread. Due to a boat reconfiguration, I'm switching from 2 of the old style 6 gallon OMC tanks to a single 12 gallon aluminum tank. The old tanks were sealed and the 12 gallon tank is vented. Even though I purchase non-ethanol gas, I was still considering a fuel water separator filter. It seems like I'm the only person using 1/4" fuel hose, which makes matching all the parts a little difficult. Some of these smaller in-line filters are not 1/4", and the Racor are over $100.

I ordered the Yamaha style on Amazon for 60, then happened to see an Attwood branded one at Walmart for $25 filter and all (I will have to purchase barb fittings) and cancelled the Amazon order. It accepts the same Yamaha filters and I imagine you could either get 1/4" barbs or adapt them down.

Might not be a bad time to get a new hose though, 3/8ths would have less restriction for your fuel pump and we're adding restriction with the filter anyway.

 

[Al U Minium]

For old engines not designed for ethanol, I think it is an extremely bad idea to use ethanol gas.

I could write about this at length, but it's pointless if you think additives and filters are going to make it all good to use it in a gasoline vintage engine.

 

[el_cheapo]

For old engines not designed for ethanol, I think it is an extremely bad idea to use ethanol gas.

I could write about this at length, but it's pointless if you think additives and filters are going to make it all good to use it in a gasoline vintage engine.

I don't disagree and I purchase it when I can I have limited availability.

 

[AlanT]

For old engines not designed for ethanol, I think it is an extremely bad idea to use ethanol gas.

I could write about this at length, but it's pointless if you think additives and filters are going to make it all good to use it in a gasoline vintage engine.

I don't disagree with your recommendation due to the hygrosopic nature of ethanol absorbing water. I avoid ethonol gas for this reason. My 1985 70hp Evinrude manual states it can use "gasohol" as defined as up to 10% ethyl alcohol. It does not recommend gas containing methanol, but I don't think that is sold anymore. I'm certainly no expert in this but it seems ethanol could be used with a treatment to minimize water absorption if that is all that is available, and better to use more quickly than let it sit.

el-cheapo, is the 120A for diesel only? I see references to diesel but none for gasoline.

 

[el_cheapo]

I don't disagree with your recommendation due to the hygrosopic nature of ethanol absorbing water. I avoid ethonol gas for this reason. My 1985 70hp Evinrude manual states it can use "gasohol" as defined as up to 10% ethyl alcohol. It does not recommend gas containing methanol, but I don't think that is sold anymore. I'm certainly no expert in this but it seems ethanol could be used with a treatment to minimize water absorption if that is all that is available, and better to use more quickly than let it sit.

el-cheapo, is the 120A for diesel only? I see references to diesel but none for gasoline.

The Racor brand states gas, diesel, or gas oil blends.

https://www.jmesales.com/racor-120a...ter-separator-120a-filter-assembly-10-micron/
Looks like some of the cheap filters/bowls on amazon can't handle the gas but the head it screws into is either aluminum or SS so I think you could go buy a cheaper head and buy a higher grade filter assembly if you wanted.

 

[AlanT]

The Racor brand states gas, diesel, or gas oil blends.

https://www.jmesales.com/racor-120a...ter-separator-120a-filter-assembly-10-micron/
Looks like some of the cheap filters/bowls on amazon can't handle the gas but the head it screws into is either aluminum or SS so I think you could go buy a cheaper head and buy a higher grade filter assembly if you wanted.

Cool. I noticed this one is 1/4" port size. I'm trying to figure out the difference between this one and the 120R-RAC-01 other than flow rate, which shouldn't matter.

https://www.marineengine.com/newparts/part_details.php?pnum=RAC120R-RAC-01

 

[airshot]

Amazing to see how far all these ethenol stories have advanced thru the years. Almost as bad as climate change and global warming !! Great humor reading all the horror stories about ethenol fuels. Kinda like the gas car causing all of our climate changes. To each his own, your money, do what makes you feel better. Bottom line is...it all comes down to quality of fuel and maintenence !!! When ethenol gas came out, there were thousands of memos about what to change or modify to make your engine compatible with E10 !! How many folks made those changes ?? Mfgrs made the changes immediately so your vehicle is already compatible if made after E10 introduction !! Filters and gas additives were around long before E10 was put on the market, so anyone that thinks a non ethenol gas is the answer doesn't remember history very well. Yes...E10 fuels do require a little more diligence to maintain them them, but no maintainence is bad for any fuel and that is where the problems begin !!

 

[el_cheapo]

Amazing to see how far all these ethenol stories have advanced thru the years. Almost as bad as climate change and global warming !! Great humor reading all the horror stories about ethenol fuels. Kinda like the gas car causing all of our climate changes. To each his own, your money, do what makes you feel better. Bottom line is...it all comes down to quality of fuel and maintenence !!! When ethenol gas came out, there were thousands of memos about what to change or modify to make your engine compatible with E10 !! How many folks made those changes ?? Mfgrs made the changes immediately so your vehicle is already compatible if made after E10 introduction !! Filters and gas additives were around long before E10 was put on the market, so anyone that thinks a non ethenol gas is the answer doesn't remember history very well. Yes...E10 fuels do require a little more diligence to maintain them them, but no maintainence is bad for any fuel and that is where the problems begin !!

I figure ethanol or not, a decent filter is going to be a good addition. Fuel could have crud in it from any step of the way. Ethanol, octane, the word "premium" doesn't stop water from getting in the gas stations tanks, which get stirred up every delivery, hopefully the filter at the pump is effective (Can't be that great look at the volume/speed they have to endure), did your oil mix bottle accumulate a little dust around the lid, it's endless might as well filter the final step.