1979 Mercury 90hp Fuel Filter

[MikeH2]

I am working on a 1979 Mercury 90hp Outboard SN: 5495***. It has been sitting since 2001. I had the carbs pulled off and gone through, replaced impeller and gaskets, and cleaned off the spark plugs when I looked at them. I know NOTHING about outboards and need help. I had a buddy tell me that I should always have a fuel filter inline. He recommended picking one up Auto/Checker Zone and just make sure it fit my 3/8th's line. I picked up the one in the pic below and installed it inline. I know I have some wiring issues that need to be addressed soon (corrosion, cracked insulation, ect.) but I am wondering if this filter is too big, let's too much air in the line, (can?t seem to keep it full of fuel) is it suppose to be full all the time or just have a level line of fuel? Should I just get the $13 one at the boat store? The only difference I see is that it is narrower than the one I picked up. I plan on getting the fuel pump kit and doing that as well. Is there another filter I should be looking at?

 

[ENSIGN]

Re: 1979 Mercury 90hp Fuel Filter

Install a water seperating filter between the primer bulb and engine for best protection.check all the fuel lines, the gray mercury fuel hose falls apart on the inside after several years.

 

[MikeH2]

Re: 1979 Mercury 90hp Fuel Filter

Thanks...So is it OK to use the "car" fuel filter? Is it normal for the fuel level visible in the clear filter to not be full? Do I need to get one specifically for marine applications?

 

[Chris1956]

Re: 1979 Mercury 90hp Fuel Filter

Mike, I do not think the filter is the issue. The fuel is clear, which means it doesn't have any 2 cycle oil mixed it. I do not think the '79 motors had oil injection, so you motor is likely to seize, if you try to run it.

 

[MikeH2]

Re: 1979 Mercury 90hp Fuel Filter

I have added oil every time I add fuel. (50:1) its a dark green looking oil. Not sure why it has not discolored the fuel more. I believe that is the right mix, is it not? In the pic I posted there was also a bottle of Seafoam added to the 5 or so gal's of fuel, would that make it look clearer? Thanks

 

[oldnhbuck]

Re: 1979 Mercury 90hp Fuel Filter

Hi I have the same engine..# 5221199....90 hp
mine had been "sitting" fo a while too..and same results when attempting to start..I replaced ALL fuel lines..and also installed a water separator filter assy between fuel pump and gas can(s)..
perhaps a fuel pump rebuild kit is in order..(and NO..inline clear filter doesn't have to be "full" to be operating properly..)

 

[MikeH2]

Re: 1979 Mercury 90hp Fuel Filter

Thanks oldnhbuck! $7 dollars ain't bad for piece of mind on the fuel pump.