'76 Evinrude 70hp Fuel Pump

['76 Sea Sprite]

Greetings boating friends,
I'm a newbie to the boating world, please be gentle. I purchased my first boat and was told that the fuel pump needed to be rebuilt. The reason for this, according to the seller, is because raw fuel is dumping into the #3 cylinder. His description to me as to how the system works is that the #3 cylinder produces vacuum that operates the fuel pump. He went on to explain that if the fuel pump diaphragm has a hole in it, that would cause the raw fuel to go into cylinder #3. Does this sound like a reasonable diagnoses? Is this a difficult repair for the average person? and last, Can you recommend the part number to order? Thank you in advance and I hope to return the favor as I learn about this boating hobby.

 

[Bumpa53]

Re: '76 Evinrude 70hp Fuel Pump

The explanation is one possible answer.

To verify the statement; Is the #3 plug wet & oily ? Is there good spark at #3 plug ?

To check the pump: disconnect the vacuum line from the pump to the #3 case vacuum port.
Pump the primer ball (engine OFF). If fuel comes out the vacuum line then the pump diaphragm is leaking.

If the pump checks OK suspect a stuck float on #3 carb or misadjusted (Rich) idle jet (if yours is adjustable).

Check the iboats parts site for parts description.

B53

 

[jtexas]

Re: '76 Evinrude 70hp Fuel Pump

... Is this a difficult repair for the average person? ...

Pump repair kit: the manual says these are "throwaway" pumps, but sierra part #18-7820 will fit. About $11 on iboats.
You'll need a can of gasket remover spray and permatex #2, and about an hour.
Pay close attention during disassembly so you can get all the parts back in the right order.
Take care not to score the housing when removing the old gasket material.

But do follow Bumpa's test procedure first.

welcome to boating...if you're the least bit handy (and you better be if you want to own a boat), there's nothing that can break down on that motor that you can't fix with some basic tools, a little determination and a good service manual. I highly recommend the factory shop manual.

Change the water pump impeller every 2 years, and gear oil annually. Your motor will run best on Champion QL77JC4 spark plugs.

 

['76 Sea Sprite]

Re: '76 Evinrude 70hp Fuel Pump

Thank you for all the information. I'll follow the directions that you have so kindly offered. I'll start by ordering a shop manual and progress from there. Thank you again.

 

[jtexas]

Re: '76 Evinrude 70hp Fuel Pump

...oops...