spin-on gas filter

[Prophammer]

Can I use a spin-on gas filter on my Mercury 9.9 carbureted outboard? It has an inline filter but that doesn't stop water from coming through, I need something better than the inline filter. Please let me know thanks.

 

[airshot]

Why you you have water comming thru ? Portable tank or running off a main built in tank ? I would be more concerned with the water scource...

 

[Prophammer]

Portable tank, I suspect water came in through a crack in the vent and I was unaware and it got in my carb. I would like a spin-on filter that could catch the small amounts of water but I don't know if it will run right with a spin-on filter on it , never saw one on a portable outboard, will it work?

 

[flashback]

That's a good question, I don't know how it would react to pre mixed fuel. You sure don't want to filter the oil out...

 

[topgun3690]

Shouldn't need a water separator filter on a portable tank as you can just dump it out if water gets in there. Hard to do with a built in tank. It could work but the filter would have to be mounted somewhere in a vertical position in the boat, then connect your portable tank to it. Probably overkill for a small outboard.....This Racor Snapp filter would do the job if you went that route.....it's not a spin on, is a disposable unit with a drain on the bottom. FYI

 

[topgun3690]

That's a good question, I don't know how it would react to pre mixed fuel. You sure don't want to filter the oil out...

The oil is in solution.....it cannot be filtered out.

 

[Prophammer]

it is a 4 stroke so no oil would go through it , I like the Racor filters was also thinking from JF marine

 

[topgun3690]

All it is is money.....am no expert, but you don't want a filter that would cause a problem with fuel flow.....not sure how strong the fuel pump is on your 9.9hp.....it will have to be able to suck fuel through whatever filter you get.

 

[roscoe]

Smaller boat, exposed area where filter would be located???? You don’t want the filter drain to get bumped or broken.

Go with an all metal spin on filter.

It will work fine with the small motor.
I have used them with 6 hp, 8 hp, and 15 hp mercury motors for years. The filter is not restrictive, unless you plug it up with dirt.

 

[topgun3690]

If the filter will be totally exposed, then roscoe is right.....the all metal spin on would be the better choice.....and fuel flow shouldn't be a problem either.

 

[dingbat]

...

 

[Prophammer]

Metal spin on sounds good thanks for letting me know they work good on 8 and 9.9

Smaller boat, exposed area where filter would be located???? You don’t want the filter drain to get bumped or broken.

Go with an all metal spin on filter.

It will work fine with the small motor.
I have used them with 6 hp, 8 hp, and 15 hp mercury motors for years. The filter is not restrictive, unless you plug it up with dirt.

Roscoe, where I'm going to mount it, It will get just a little back wash over the transom - I will get a metal spin-on , and I'm glad to hear you've done it before, I plan to spin a new one on it every season , thanks for the info!

 

[jimmbo]

A large Water Separator Filter will not create a Pressure Drop that would hinder the Fuel Pump from operating. Those small inline Filters are more restrictive, than a large Spin-on

 

[dingbat]

Smaller boat, exposed area where filter would be located???? You don’t want the filter drain to get bumped or broken.

The sight bowls are heavy duty. You would damage the metal filter shell before you damaged the sight bowl.

But, I could see concerns with damaging the 2-turn drain screw assembly if the unit was mounted in a location with a high probability of being damaged.

In that case, I would simply go with the brass, screw in drain plug.

 

[Prophammer]

I was planning on keeping the inline filter under the cowl and add the spin-on filter outside the cowl on the pressure side of the primer bulb. 10 microns spin-on. I never know what will be going on in the boat out on the river, I would like the filter and housing to be all metal in-case it gets hit by something. Does that sound like it will work?

 

[dingbat]

I never know what will be going on in the boat out on the river, I would like the filter and housing to be all metal in-case it gets hit by something. Does that sound like it will work?

Not a fan of in-line rock and stick catchers. They are redundant and something else to go wrong.

Got to ask, where are you going to mount this thing?

I would be more concerned about ripping the mounting bracket off the "wall" than damaging a sight glass

 

[airshot]

Not a fan of in-line rock and stick catchers. They are redundant and something else to go wrong.

Got to ask, where are you going to mount this thing?

I would be more concerned about ripping the mounting bracket off the "wall" than damaging a sight glass

Interesting....never had an issue with inline filters, other than people using the wrong size. On my current motor it uses a 3/8" ID fuel line but the previous owner used a 1/4" ID filter, claims the dealer installed it. Had a slight leak issue so I replaced it with a 3/8" inline filter and it actually runs better at wot, or it seems to anyway.. I like them because they are clear and I can see any crap that gets in there. Had the big canister type on my bigger boat but couldn't see thru it, when I did have issues I had to take them apart to find the problem, rather than just looking thru them. Tobeach his own I guess...

 

[Prophammer]

I think I'm going to bolt the spin-on filter inside, at the top of the transom board , site glass might be nice - please see pics

 

[dingbat]

Had the big canister type on my bigger boat but couldn't see thru it, when I did have issues I had to take them apart to find the problem, rather than just looking thru them.

Great testimony as to why one should install a quality 10 micron, canister filter with clear bowl and drain.

 

[Prophammer]

dingbat per airshot, very good point , a plastic site glass can be very hard to see thru after a few years of exposure , I'll post another picture of my fuel system when I get it together, Thanks and thanks to all who contributed some of their knowledge