Should I install Fuel/Water Separator?

[JM3820]

I have a 1998 Maxum 1800SR with a 1988-92 Mercruiser block (serial# 0C319801). i has a mechanical fuel pump with an fuel filter on it and a screen at the 2bbl carb. I am considering installing a fuel/water separator because I'm in a humid environment.

What type of fuel/water separator should I install for this size of engine?

 

[Bondo]

I have a 1998 Maxum 1800SR with a 1988-92 Mercruiser block (serial# 0C319801). i has a mechanical fuel pump with an fuel filter on it and a screen at the 2bbl carb. I am considering installing a fuel/water separator because I'm in a humid environment.

What type of fuel/water separator should I install for this size of engine?

Ayuh,..... Welcome Aboard,...... You can't go wrong using the standard Mercruiser filter, 'n housing,.....
The Merc housing uses the napa 3225 or 3226 filters,.....

 

[QBhoy]

You’ll already have a standard type fuel filter with water separating capability. Although it’s not the type that has a separating bowl…with regular changes at the right intervals…they’ve done a great job so far, over the last few decades. Keep the fuel fresh and you’ll be fine.

 

[Scott Danforth]

I have a 1998 Maxum 1800SR with a 1988-92 Mercruiser block (serial# 0C319801). i has a mechanical fuel pump with an fuel filter on it and a screen at the 2bbl carb. I am considering installing a fuel/water separator because I'm in a humid environment.

What type of fuel/water separator should I install for this size of engine?

your boat was originally fitted with a fuel / water filter. my guess is they did not retain that when they dropped in an older motor

 

[achris]

your boat was originally fitted with a fuel / water filter. my guess is they did not retain that when they dropped in an older motor

Actually, that engine did not come with a spin-on water sep fuel filter. It has a small filter element inside the fuel pump, but nothing else.

What type of fuel/water separator should I install for this size of engine?

The standard Merc spin-on filter kit is the best you could get.

Merc part number is: 35-802893Q4 (Less than 60 of your dollars)
Other companies like Sierra and GLM make the kits too, but as much as I dislike Merc (personal reasons!) their products are pretty much unbeatable.

Chris........

 

[Lou C]

Agreed the Merc standard unit is the best for what you have & gives you a wide range of filters you could use from the standard ones to a Racor with the metal bowl. If in a humid environment and forced to use E10 gas it’s pretty much necessary to avoid fuel system problems.

 

[Chris51280]

I didn't have one on my 90's 4.3 originally either. Added one and have no problems. I change it once a year. I also changed the filter in the pump. The spin on filter will take everything out since the one in the pump is rather small.

 

[QBhoy]

Actually, that engine did not come with a spin-on water sep fuel filter. It has a small filter element inside the fuel pump, but nothing else.


The standard Merc spin-on filter kit is the best you could get.

Merc part number is: 35-802893Q4 (Less than 60 of your dollars)
Other companies like Sierra and GLM make the kits too, but as much as I dislike Merc (personal reasons!) their products are pretty much unbeatable.

Chris........

Ah. I presumed this was a 4.3. Not a 3.0. Fair play

 

[achris]

Ah. I presumed this was a 4.3. Not a 3.0. Fair play

It is a 4.3. Before 1992, the only fuel filter was the small one inside the mechanical fuel pump. Based on the serial number, the engine is 1988.

Chris.

 

[Scott Danforth]

It is a 4.3. Before 1992, the only fuel filter was the small one inside the mechanical fuel pump. Based on the serial number, the engine is 1988.

Chris.

but the boat is a 98. and I believe starting in 1997 the 4.3's came with a fuel water separator

 

[achris]

but the boat is a 98. and I believe starting in 1997 the 4.3's came with a fuel water separator

Don't really care what year the boat is. The water sep filter is part of the engine, not the boat.... And Merc started put water sep filters on in 1992 (the horrible metal can ones, not spin on). Spin ons started mid 93...

Chris

 

[QBhoy]

It is a 4.3. Before 1992, the only fuel filter was the small one inside the mechanical fuel pump. Based on the serial number, the engine is 1988.

Chris.

My 1990 definitely had the usual fuel water separating filter Chris. Was on a bayliner 2255. Also had one on a VP 4.3 from 1989 too.

 

[Lou C]

Came standard on my 1988 OMC.

 

[achris]

My 1990 definitely had the usual fuel water separating filter Chris. Was on a bayliner 2255. Also had one on a VP 4.3 from 1989 too.

Merc produced a kit to retrofit the metal can filter to spin-on. Quite a lot of pre-93 engines also got the kit fitted, as it's the easiest way to put an 'external' filter on them. Is your filter on the starboard side of the engine, just forward of the engine mount? Or mounted to part of the boat (inside the engine bay)?

Chris.

 

[QBhoy]

Merc produced a kit to retrofit the metal can filter to spin-on. Quite a lot of pre-93 engines also got the kit fitted, as it's the easiest way to put an 'external' filter on them. Is your filter on the starboard side of the engine, just forward of the engine mount? Or mounted to pay of the boat (inside the engine bay)?

Chris.

Hi Chris. To be fair, the 1990 merc 4.3 filter was mounted on the bulkhead forward of the engine.
But I think the 89 vp 4.3 was mounted on a bracket on starboard side of the engine

Merc produced a kit to retrofit the metal can filter to spin-on. Quite a lot of pre-93 engines also got the kit fitted, as it's the easiest way to put an 'external' filter on them. Is your filter on the starboard side of the engine, just forward of the engine mount? Or mounted to part of the boat (inside the engine bay)?

Chris.

Hi Chris. To be fair, the 1990 merc 4.3 filter was mounted on the bulkhead forward of the engine.
But I think the 89 vp 4.3 was mounted on a bracket on starboard side of the engine

 

[achris]

With the advent of the electric fuel pump Merc put a filter on as standard. The first generation of filter was a disposable metal can. About a year later they made the can NLA and provided a kit to retrofit it to a spin-on.



Before than, any spin-on filter fitted to the engine was put on 'after the fact', probably by the owner. And that retrofit kit was best way to get all the bit you needed to fit the filter housing to the engine. The 'standard' filter kit is design as a bulkhead mounted unit, not engine mounted. Any bulkhead mounted filter is not 'standard engine equipment', even if it is 'Mercruiser' branded....

Chris.........

 

[QBhoy]

With the advent of the electric fuel pump Merc put a filter on as standard. The first generation of filter was a disposable metal can. About a year later they made the can NLA and provided a kit to retrofit it to a spin-on.

View attachment 357006

Before than, any spin-on filter fitted to the engine was put on 'after the fact', probably by the owner. And that retrofit kit was best way to get all the bit you needed to fit the filter housing to the engine. The 'standard' filter kit is design as a bulkhead mounted unit, not engine mounted. Any bulkhead mounted filter is not 'standard engine equipment', even if it is 'Mercruiser' branded....

Chris.........

With the advent of the electric fuel pump Merc put a filter on as standard. The first generation of filter was a disposable metal can. About a year later they made the can NLA and provided a kit to retrofit it to a spin-on.

View attachment 357006

Before than, any spin-on filter fitted to the engine was put on 'after the fact', probably by the owner. And that retrofit kit was best way to get all the bit you needed to fit the filter housing to the engine. The 'standard' filter kit is design as a bulkhead mounted unit, not engine mounted. Any bulkhead mounted filter is not 'standard engine equipment', even if it is 'Mercruiser' branded....

Chris.........

I’ve actually got an old picture of the engine somewhere. See if I can find it.

 

[QBhoy]

With the advent of the electric fuel pump Merc put a filter on as standard. The first generation of filter was a disposable metal can. About a year later they made the can NLA and provided a kit to retrofit it to a spin-on.

View attachment 357006

Before than, any spin-on filter fitted to the engine was put on 'after the fact', probably by the owner. And that retrofit kit was best way to get all the bit you needed to fit the filter housing to the engine. The 'standard' filter kit is design as a bulkhead mounted unit, not engine mounted. Any bulkhead mounted filter is not 'standard engine equipment', even if it is 'Mercruiser' branded....

Chris.........

They both had the filter on the engine actually. The mercruiser was 1990. The VP an 89. The VP also had a pre filter on the bulkhead.

 

[achris]

How sure are you that the Merc is 1990? Because everything I see on that engine says 1992, and they had the metal can filter, which had to be changed to the engine mounted spin-on (as the metal can was NLA and superseded to the spin-on kit)...

 

[QBhoy]

How sure are you that the Merc is 1990? Because everything I see on that engine says 1992, and they had the metal can filter, which had to be changed to the engine mounted spin-on (as the metal can was NLA and superseded to the spin-on kit)...

Pretty certain of it Chris. Although I bought the boat used…the boat was on the Loch here since brand new when she was imported and supplied to the original owner through Windermere aquatics (along with another 2 identical that year). Neither of these engines had an electric fuel pump I’m sure. The Vp I can say for certain didn’t. Only filter I remember being different from the rest of the GM engines I’ve had, was the oil filter.