fuel pump ? please help 79-70hp

[jjacobs007]

hello, thanks for taking the time to help me.I have a 70hp johnson (1979)my fuel pump # is 343462 on the back metal part.it says there not rebuildable.on the front plastic theres the number 438559.i believe this is the wrong pump my boat runs but when i go to take off it mostly hesitates and i wait for the rpms to pick up before gunning it.i have rebuilt the carbs,new power pack,coils,wires,and plugs.Also my carbs have three orifices when i believe there should only be two.any help would be awesome.

 

[ezeke]

Re: fuel pump ? please help 79-70hp

The original fuel pump on your engine was 0385784, which has been superseded by 0395712,0398385,0433390,and now 0438559.

0438559 is rebuildable with the proper repair kit (0438616).

The fuel pump just keeps the float bowl full, the engine then pulls the fuel from the float bowl with the vacuum created by the movement of the pistons. Your problem is most likely caused by improper or dirty jets (orifices) in your carburetors.

Each of the original carburetors on your engine had three orifices. Please click the thumbnail.

It's extremely important that the throttle plates on your engine's carburetors are perfectly synchronized, so take the air silencer off and watch them as you move through the range. They should be fully closed at idle and perfectly horizontal at WOT and always moving together, perfectly synchronized.

 

[jtexas]

Re: fuel pump ? please help 79-70hp

have the same motor...the manual says it's a throwaway pump but sierra part number 18-7820 repair kit fits it just fine.

the seloc manual is kind of ambiguous, implies that motor has 2-jet carbs, but three jets is correct -- I highly recommend the OEM manual. much more clear on this and many other subjects.