Where is my fuel filter? 1987 merc 5.7L

jlucas209

Seaman Apprentice
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Aug 4, 2014
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37
So my engine died randomly and couldn't get it to fire back up. Took it home let it sit for a few days and it fired right back up and died several moments later, tried to start it and it took several attempts but it started.. I ran some seafoam through the engine and haven't been able to replicate the problem. I haven't took it back out on the water yet. Anywho I assume it was a fuel or electrical related problem, so I replaced the ignition coil just because I had a new one handy. I was going to replace the fuel filter but I'm barely noticing I don't think I have one, it seems to be removed and bypassed by the previous owner (I purchased the boat last summer). Am I missing the filter location? If not why in the would would anyone bypass it, what is the advantage? Should I gather the parts to add it back or should I be fine? I ran it like this all last summer with no issues. Engine is an 1987 ski competition mercruiser 350 5.7L
 

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Bt Doctur

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Aug 29, 2004
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19,452
I only see the rubber hose connecting directly to the fuel pump. , but what is that small hose coming from the circulating pump? Is it for the shaft log seal for the inboard shaft?
 

ThomW

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Aug 8, 2016
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Did you check the fuel filter in the bottom of fuel pump too?
 

jlucas209

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Aug 4, 2014
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I only see the rubber hose connecting directly to the fuel pump. , but what is that small hose coming from the circulating pump? Is it for the shaft log seal for the inboard shaft?

That goes to the back of the engine somewhere, cant remember exactly (I'm at work now). I only have a hose going directly to fuel pump (from tank) then the fuel line going straight to the carb.
 

alldodge

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Your boat has a standard mechanical fuel pump (filter is not part of the pump) and should have a remote canister filter.

http://www.mercruiserparts.com/bam/s...31741/1014/120

Appears someone removed it. Would also look close at the fuel pump to see if it has tubing going from it to the carb. Someone removing the filter may have also put a standard automotive pump in its place

The filter needs to be added back in
 

jlucas209

Seaman Apprentice
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Aug 4, 2014
Messages
37
Your boat has a standard mechanical fuel pump (filter is not part of the pump) and should have a remote canister filter.

http://www.mercruiserparts.com/bam/s...31741/1014/120

Appears someone removed it. Would also look close at the fuel pump to see if it has tubing going from it to the carb. Someone removing the filter may have also put a standard automotive pump in its place

The filter needs to be added back in

OK so I am not overlooking it, someone did remove it. Yes I do have a clear vent tube going from the pump to the carb, it just looks white/yellowish in the pic but it's there.
 

alldodge

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looks white/yellowish in the pic but it's there.

Your good there

Suggest checking fuel pump pressure by placing a tee fitting between carb and pump. Pressure should be 3 to 7 psi
 

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,259
carefully follow the fuel line back to the tank. Some ski boats like to mount the filter back by the tank to get it in a cooler location to help with vapor lock.
 
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