Fuel Filter Swap Out Questions

Boilers2000

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Before the start of boating season I want to swap out the stock fuel filter and swap in a fuel water separator filter. My questions are:
1. Any recommendation on where to mount?
2. Does the stock fuel pump have enough push for this type of filter? It's the stock fuel pump.
3. Type of fuel line tubing needed?

The engine is a '92 4.3LX.

Thanks
 

Bondo

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Before the start of boating season I want to swap out the stock fuel filter and swap in a fuel water separator filter. My questions are:
1. Any recommendation on where to mount?
2. Does the stock fuel pump have enough push for this type of filter? It's the stock fuel pump.
3. Type of fuel line tubing needed?

The engine is a '92 4.3LX.

Thanks

Ayuh,..... Use a Merc filter, or an aftermarket filter mount, that uses the Merc thread pitch filters,......

Mount it anywhere 'tween the fuel tank outlet, 'n fuel pump, preferably where it's easy to change,.....

The fuel pump will be just fine,.....

Use CG approved fuel hose,.....
 

Boilers2000

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I found a merc kit that has a bracket and it says it for 92 4.3's. Feel like it's a tube pipe from the outlet of the filter into the pump? Didnt think you could use rubber tubing on the high pressure side?
 

Bondo

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Feel like it's a tube pipe from the outlet of the filter into the pump? Didnt think you could use rubber tubing on the high pressure side?

Ayuh,..... Not sure I understand,.......

The filter goes before the fuel pump,......

The line from the pump to the carb could stay the same,.....
 

Boilers2000

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Can never post pictures but here is the part # Quicksilver 807172A1....I thought would work. Going to look tonight to see if I have the mounting holes, cant find online instructions, but it looks like the filter has to mount close to the fuel pump.
 

dingbat

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That filter is crazy priced.

You can buy one for less than half that price
 

Bondo

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but it looks like the filter has to mount close to the fuel pump.

Ayuh,...... Usually it's a little flat plate that bolts to the front of the exhaust manifold, 'n the filter housin' bolts to the plate,....
 

Boilers2000

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Does it use existing bolts into the manifold? Cant find a good picture or diagram to see how it attaches.

Agree it's an expensive kit, but it looks like the bracket is about 75 on it's own. If I could find one locally I would buy one to trace the dimensions and make it myself.
 

Bondo

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Ayuh,..... I can't see yer motor,......

Usually there's a threaded hole or 2 on the front face of the manifold,.....

I would probably just get creative, 'n build a bracket/ plate to mount the filter too,.....
 

achris

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As you're aware, your existing setup uses an obsolete filter. The superseded part number kit comes with everything you need to convert it to the new setup, complete with a water separating filter, and all the bolts, brackets and tubes you need.

https://www.mercruiserparts.com/8071...ilter-kit-fuel

The mounting bracket does not bolt to the manifold, it picks up the top 2 screws of the starboard engine mount. The drawing below is the only one I could find in the manuals. It's a view from in front of the starboard side of the engine looking back. Once you see where the filter is designed to sit, working out where the brackets go is easy... (I have done a Q&D drawing of how the bracket mounts... Sorry about the rubbish 'paint' skills)...

Just add the barb for the incoming fuel line and that kit is all you need. If the cost is too high, just buy a bulkhead mounted water sep filter bracket and run a USCG approved flexible hose from the filter out to the inlet side of the pump. Anything on the inlet (suction) side of the pump is low pressure. In fact, when the engine is running, it's usually at a slightly lower pressure than ambient.

When you put the fittings into the filter mount, DO NOT over-tighten. The mount is cast aluminium and will crack at even the slightest hint of over-tightening. Then you'll have air and not fuel being sucked into the pump. Engine's really hate that. ;)

Chris.........
Click image for larger version  Name:	filter.JPG Views:	1 Size:	108.1 KB ID:	10833565
 
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Boilers2000

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Thanks AChris...that was extremely helpful! One more question...for any threaded connections do you use pipe dope or teflon tape?
 

Boilers2000

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Another question.... can you remove those bolts with the engine in the boat...assuming the 3 other mounts will hold the engine in place but thought I'd ask.
 

achris

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If you use tape, make sure none of it crosses into the inside. I prefer to use Loctite 567, as a lubricant, NOT a sealer. The sealing is done by the thread form, not tape or paste.

Chris.....
 

achris

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Another question.... can you remove those bolts with the engine in the boat...assuming the 3 other mounts will hold the engine in place but thought I'd ask.

As long as you leave the bottom screw in place (and there's no reason not to), that mount won't move. Use the 2 new, slightly longer, screws that come in the kit to replace the 2 you remove from the top of the mount..

Chris........
 
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