gasoline filter changes

[Gary Brickell]

I have a Campion 310 trawler with a 3.7L 4cyl 190hp Merc gas inboard. I read a lot of posts about regularly changing out diesel filters, but very little about gas filters. Are diesels more fussy about clean fuel than gas engines?

 

[Gdavid]

I have a Campion 310 trawler with a 3.7L 4cyl 190hp Merc gas inboard. I read a lot of posts about regularly changing out diesel filters, but very little about gas filters. Are diesels more fussy about clean fuel than gas engines?

The majority of filter discussion on this site is diesel because most of the boats we consider recreational "trawlers" are diesel powered. Gas filtration is important but the age and quality are equally if not more important. Your carbureted engine is less fussy about fuel cleanliness than a modern fuel injected engine but aging ethanol or regular old petroleum gasoline lose octane with age and can varnish up carburators.

Those 3.7 mecruisers are odd ducks, I would collect every spare part you can for it.

 

[Cleanslate]

Gas Does not build up the snot algae and skank that diesel can . In general, it stays cleaner , longer.
Both have their limitations.
Water intrusion kills both.

Keep your tanks , deck fills, hoses tight and dry.

 

[rslifkin]

Gas tanks tend to stay cleaner as mentioned. On my gas boat I tend to change the filters every year or 2 depending on usage.

 

[Bacchus]

IMO and AFAIK diesel ages better than gas provided the moisture is kept out of the system.
Gas especially ethanol does not age well and treatment get you a year or so?
I would sooner run 5 yr old diesel than 5 yr old gas provided they are both water free. Ethanol absorbs atmospheric moisture.

 

[Comodave]

IMO and AFAIK diesel ages better than gas provided the moisture is kept out of the system.
Gas especially ethanol does not age well and treatment get you a year or so?
I would sooner run 5 yr old diesel than 5 yr old gas provided they are both water free. Ethanol absorbs atmospheric moisture.

Oh, absolutely. If the gas has ethanol in it without, and even maybe with, stabilizing the fuel it can go bad and phase separate in a few months. If you can buy non ethanol gas it can last for years with stabilization. Here they call non ethanol gas rec gas. I have used 5 year old rec gas without any problems.

 

[rslifkin]

For gas, storage conditions matter a lot. The better sealed the tank, the longer the fuel lasts (with or without ethanol).

 

[Pete Meisinger]

Diesel engines are more particular than gas engines. For a small gas engine like you have an in line filter should do the job. Maybe change it once a year.

pete

 

[Gary Brickell]

Thank you all for the info. My home port sells mid grade non-ethanol marine gas only and I have never had any issues. Where I boat on the Trent-Severn waterway diesel fuel is rare only about 20% of fuel docks sell it. Plus it costs 30% more than marine gas. Around these parts gas is the more economical way to go. I appreciate your comments about filters.

 

[Cleanslate]

Hey Gary that's a nice boat you have. Never heard of a Campion 31. Looks roomy for it size. I guess you are the lock master ! Wow , lots O locks on your waterway. Looks like fun. Enjoy the upcoming season.

I have both gas , single inboard 350 22' boat and a 42' twin diesel boat. Water intrusion is the main problem for both AND lack of use. 100 hrs a year or more is a good thing. Keeps fresh fuel in the tanks and keeps the vessel broken in.IMO.

 

[RT Firefly]

Greetings,
Mr. GB. We have a gas Mercruiser (V8) on the Rideau. Non-ethanol fuel (so I'm led to believe), Sta-bil fuel stabilizer and filter changes every 2 years, or so, is my regime. Brand new tanks this year and I will continue as in the past.

We have a remote canister fuel filter and put on about 75+ hours/ year (aprox.). No problems in the last 6 years.

 

[kthoennes]

We have twin 454's, gas of course, fuel injected, and I change the filters twice every season -- once after spring launch and then again usually around August. Water intrusion. Our deck plate (cap) is tight with a good gasket, but I think it's winter condensation with long periods of freeze/thaw. I also think the filter canisters spec'd for those (Marine Power/GM) engines are too small for how much gas they drink. The can itself is only like three inches tall. One side will take a bigger can so I use a bigger alternative, but there's not enough clearance on the port engine to use a bigger one. I thought about re-running the (metal) fuel lines to make room for second or bigger filters, but fuel injection is so sensitive I'm reluctant to mess with it.

 

[rslifkin]

We have twin 454's, gas of course, fuel injected, and I change the filters twice every season -- once after spring launch and then again usually around August. Water intrusion. Our deck plate (cap) is tight with a good gasket, but I think it's winter condensation with long periods of freeze/thaw. I also think the filter canisters spec'd for those (Marine Power/GM) engines are too small for how much gas they drink. The can itself is only like three inches tall. One side will take a bigger can so I use a bigger alternative, but there's not enough clearance on the port engine to use a bigger one. I thought about re-running the (metal) fuel lines to make room for second or bigger filters, but fuel injection is so sensitive I'm reluctant to mess with it.

If you're getting water in the filters, there's likely a good bit puddled in the bottom of your tanks. That'll eat the tanks over time, and if you ever have to take on ethanol containing gas, it'll be at risk of separating immediately.

I'd try to get the water out of the tanks, even if that means adding a ton of something like iso-heet to absorb the water and let it burn through the system.