1977 Merc 7.5 priming

[ajcampbell31]

So I have never had a motor with an external tank before. I know that the motor needs to be primed from the tank itself, but how can I tell if I am under or over priming? I don't want to blow out or break anything from too much pressure or kill my shoulder trying to start it under primed.

 

[tpenfield]

Primer bulb squeezed and relaxed repeatedly until the bulb puts up resistance. Probably 4-6 times . . . less if it has been run recently. Then you are primed.

If the engine does not seem to be getting gas . . . prime some more.

 

[ajcampbell31]

And then once primed and running the fuel pump should have enough power to keep the vacuum and keep pulling the fuel in, correct? I see you had a 7.5 Merc, do you recommend and particular fuel tank, line, connector, etc...

I haven't ran it yet, I have to get the tank and everything first. But the person I got it from said it ran about 2 months ago before the clear tube from the fuel inlet to pump got hard and cracked.

 

[tpenfield]

Yes the fuel pump will do its thing once the line is primed.

Be sure to verify the size/type of fuel line connector that the 1977 model has. My 7.5, being a 1969 had a special sized connector that was used in only 2-3 model years. I too had to buy the fuel line and tank when I got my engine . . . the fuel line connector alone, being rare and no longer made, was about $50

Yours should be less, being a 1977 and having a different connector. Just make sure you know the type/size.

I first bought a cheaper fuel line & bulb . . . not a good thing. I ended up replacing the fuel line with the good stuff.

 

[ajcampbell31]

After doing some research I believe I need a 3/8" line and Sierra International 18-8083 3/8" Female fuel connetor

 

[merc850]

There shouldn't be any plastic lines on that motor they used rubber, if you want to keep it running right these people have many parts http://store.oldmercs.com/category_s/1965.htm