Are two fuel filters necessay?

[gustro]

Taking this one to you pros out there.
I have a 1990 Baja with the GM 4.3 and a simple two barrel carb. When I purchased the boat it only had the mesh fuel filter in the carb, no canister filter with means of water seperation. I installed a canister filter and replaced the mesh filter that goes in the carb housing. The canister filter gets replaced yearly yet I got enough sediment in my mesh filter to cause a high idle stall (about 4 seasons on the new mesh filter) so I replaced the mesh filter again. The questions is "do I need the mesh fiilter and will the carb pass the sediment w/o issues or damage"?
Kind of a pain to get at the mesh filter and would like to keep it out of the system.

 

[Don S]

Re: Are two fuel filters necessay?

Yes, you need both at this point. My question would be WHY are you getting sediment into the mesh filter past your water seperating fuel filter.
You should be running a 10 micron water seperating fuel filter, which should stop snything from getting to the carbs filter.
Have you ever taken as filter off, emptied it and put it back on? If so, that will cause it.
You should also consider cleaning the tank.

 

[gustro]

Re: Are two fuel filters necessay?

This boat did have fuel issues when I purchased it almopst 10 years ago. The tank had a leak so I pulled it, flushed, and tigged the leaky spot. This was also reason fore the canister filter install. I am just suprised that the canister would let that much sediment pass. I know it's a Quicksilver filter but not sure of the specs. Thanks for the advice as always. I think I'll go with the "better safe than sorry" motto on this one.

 

[Jeepster04]

Re: Are two fuel filters necessay?

The QuickSilver filters we were using from Walmart were something like 30 microns. Weve switched to a Sierra 10 Micron Filter once I found that out.

 

[gustro]

Re: Are two fuel filters necessay?

Good to know, Jeepster. I think I'll try a two filter/year for a couple years and disassembling them after removal to check for sediment. Don't think sediment = flushing the tank but it would make me suspicious of fumes in the aft where my original leak was and where the fuel will end up anyway.

 

[muc]

Re: Are two fuel filters necessay?

Might want to take a look at the filter in the fuel pump. If its never been changed the bowl might be getting rusty and clogging your screen in the carb inlet.

 

[cr2k]

Re: Are two fuel filters necessay?

Maybe your fuel line is rust on the inside and flaking off.

 

[gustro]

Re: Are two fuel filters necessay?

Might want to take a look at the filter in the fuel pump. If its never been changed the bowl might be getting rusty and clogging your screen in the carb inlet.

I didn't know there was a filterr inside those old pumps. I'll do some research on how to check that.

I haven't checked the fuel lines yet but there's only one steel line on the system (pump to carb) that would be easy enough to do.
Thanks, guys.

 

[ziggy]

Re: Are two fuel filters necessay?

I didn't know there was a filterr inside those old pumps.

attachment from s/m7. the filter is inside the bowl.

agreed on rust inside somewhere.
on my rig. when i got it. my fuel pump diaphram ruptured. while replacing the diaphram i noted some screws inside the fuel pump that were horrible rusty. i didn't remove the screws for fear of ruining the pump. well, even just taking the pump apart dislodged some of the rust particles.

this is after the filter in the fuel pump. i also had issues with the filter inside the fuel pump too. i figured since my boat had alledgedly sat for 15 years that inside the fuel tank was rusty. it was fine rust that would clog my filter.

instead of cleaning my fuel tank. i kept (keep) fuel filters on board.
i also changed it out 3 times that first year of ownership. 2 times the following year. last year i never changed it. i think my rusty's are gone now.
also the screen filter at the carb is now running clean also. no debrit at the end of season last year.

edit. fwiw. i don't run a water/fuel separator. i likely should, but have not had issues with water in my fuel, yet. i don't use e10 and usually keep my fuel tank fairly topped off. it's a trailer boat...

 

[Gary H NC]

Re: Are two fuel filters necessay?

His being a 1990 i doubt it has the old style pump with filter....I could be wrong though...

 

[ziggy]

Re: Are two fuel filters necessay?

His being a 1990 i doubt it has the old style pump with filter

the attachement was taken from s/m #7, pp 5B-3. s/m #7 appears to cover '83-'93 v6. the op's 1990 falls within the range. http://www.sterndrives.com/mercruisermanuals.html

I could be wrong though

me too... guess the op will have to let us know...

 

[Gary H NC]

Re: Are two fuel filters necessay?

Yea Ziggy,I was looking at the pumps listed and it shows 2 different ones.
I guess it depends on what he has or if it was replaced before...

A picture would tell the story...

 

[fishrdan]

Re: Are two fuel filters necessay?

I had a similar experience as Ziggy when I bought my 2001 Crestliner, 3.0L engine was a basket case, ripped apart by theives. The fuel pump "looked" great on the outside, but I later found out it was filled with water at sometime and had rusted up everything inside,,, it filled the carb fuel filter with rust particles.

So much for trusting a part that "looks" good

(FWIW, someone once told me that if you run a water separating fuel filter that you can ditch the carb mounted fuel filter and it's no longer needed. I didn't believe them, kept the carb mounted filter and it probably saved my carb in this instance. All those rust particles from the fuel pump would have been a real nightmare to clean out, if possible.)

 

[gustro]

Re: Are two fuel filters necessay?

Ithink ziggy is dead on, and it's the same style pump. That's the one thing in the system I haven't checked and it makes sense since it is on the load side of the canister filter. Even if I find that is the issue I'll still keep that mesh filtrer in my carb.

 

[Kainon]

Re: Are two fuel filters necessay?

Not sure what the micron spec of the mesh filter is, but there's also a paper/fiber element filter available.

Also if he has an early fuel pump with the filter on it, then it may have the ceramic filter and I've seen them dissinegrate dumping powder into the carb and carb filter.