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MerCruiser Gen II and In-line Fuel Filters

sab

Regular Contributor
2004 Cobalt -350 Mag MPI Newbie

1. Any problems with filling the new GEN II filter with gas before installing the new filter in the GEN II unit? Its installed vertically right side up -easy to do no/little spillage. Hoping it will help with priming and a very cold start. As a newbie with this boat, what you think is a obvious condition/process is sometimes not! (I do the same with oil filters.)

2. In-Line fuel filter (35-854572) upstream from Booster Pump. My fuel tank is filled with fresh fuel. The filter is located pretty low and is mounted on bilge fairing a foot or so below the booster pump. I assume the gas tank sending unit is on top of gas tank, BUT don't want a siphoning effect from the tank into the bilge. Any problems with removing the in-line fuel filter? I need time to do the replacement. The 1/2"(?) fuel line appears to disappear through a bulkhead. As I write this, I guess I should find the fuel tank (fill on on STBD side)
 
1) just the normal safety concerns with open containers of fuel.....

2) if its as you describe, there should be anti-syphon valves at the top of the dip tube (where the fuel line connects to the tank)....there may be a little fuel flow from the line but no constant stream....there should also be shutoff valves in the fuel line to permit maintenance with minimal hazard....I'd add one if not present. treat the spin on filter just like an oil filter....lube the gaskets and tighten per the directions (usually 1/2-3/4 turn more than just finger tight)...

In general, the filters on the pressure side of the pump can be primed using the pump....its the ones on the suction side that enjoy the pre-fill...
 
Makomark - thanks for the information. I think I'm going to look for that fuel tank and perform those checks as you suggest. Also to make me feel better, I think close the upstream fuel line with a pair of adjustable pliers.

Q - My manual refers to GEN II and GEN III fuel/water separators. Why did Mercury MerCruiser choose to upgrade the Generation (GEN ?) separator to version III?
Background: According to the Internet, the Gen III had some problems which I believe are fixed with the release of a new model. I haven't researched microns between the fixed metal filter (GEN II), the pleated filter (GEN III), or a pressure drop through the filter, but should I consider replacing the GEN II setup with the latest GEN III or something aftermarket?
 
I really cant give you a definitive answer or thechanges....I haven't worked at an authorized mercruiser shop for a few years.....that said, I know Merc (& the other OEMS, too) have been spending a bunch over the past 15+ years on fuel system issues (tied to ethanol and other additives)....in years past, they didn't change parts unless there was a "good reason" as the process isn't free.....you can always call the factory tech support line - they may not give a complete answer but they wont charge you either....
 
I see this thread is 3 years old but was wondering how offen (hours)you should change the in line fuel filters on a stern drive??
 
I see this thread is 3 years old but was wondering how offen (hours)you should change the in line fuel filters on a stern drive??

Ayuh,.... There shouldn't be any in-line fuel filters,...... just the canister filter just before the fuel pump,.....
 
Ayuh,.... There shouldn't be any in-line fuel filters,...... just the canister filter just before the fuel pump,.....

There is an updated inline fuel strainer before the low pressure pump, this inline strainer kit comes with all new Mercruiser Complete drop in engines......It is there to protect the low pressure fuel pump..... Change it every year......

There is a service bulletin on this.... The strainer should be added to any inboard/stern drive engine that utilizes an electric low pressure fuel pump.
 
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