rear of fuel pump dripping fuel

[cdn-pk]

Good Day,

i recently purchased a used 1977 140HP Johnson outboard, the previous owner said he rebuilt the carbs the previous summer have about 50 hrs. i've been having WOT issues(won't go past 3/4 throttle). found a kink in in the lower carb fuel line and i bunch of leaks from old crack hoses. changed them all out. i haven't water tested it yet. while idleing in in my drive way i noticed some drips coming from the rear of the fuel pump. there seems to be a small nylon pin (maybe a pressure release valve). anyway at idle it drips fuel. all my other connections are good primer bulb keeps prime. any thoughts on that damn drip?

don't want to get towed back again this week end.

also on a side note it came with a 15 pitch stainless steel prop. seems kind low to me, what is the designed pitch??

thanks guys

 

[petryshyn]

Re: rear of fuel pump dripping fuel

Hi
No leak is acceptable in the fuel system. Best replace or overhaul the pump. (possible diaphram leak)
The prop pitch will be dependent on boat, weight and usage. Wait till you have it running right, then measure you max RPM in gear at WOT.(don't exceed engine max. recommended RPM) That will help you decide if 15 is appropriate.

cheers

 

[cdn-pk]

Re: rear of fuel pump dripping fuel

i called around and i can't seem to find a rebuild kit. look like i'll have to order a new one.

what is that rear hole for???

thats it, gonna take it apart and see...

 

[ezeke]

Re: rear of fuel pump dripping fuel

The hole is for the pump mechanism to have room to breath as the diaphragm (part 13) moves up and down. The nylon pin-like extrusion is the end of a cap (part 20) that protects the diaphragm and guides the spring (part 21). When the diaphragm wears out or ruptures, fuel gets past it and can leak out or worse, pass into the cylinders.

The fuel pumps can be rebuilt using repair kits. The OEM repair kit # 0,438,616 has most of the parts. There is an aftermarket kit 18-7820 from Sierra that iboats sometimes sells that also has most of the parts and will work as well.

Click the thumbnail to enlarge and print.

 

[cdn-pk]

Re: rear of fuel pump dripping fuel

thanks ezeke! thats what i was looking for. i called a local supplier i usually go to and they don't sell repair kits, guess i'll have to call around some more. a new pump is over a c note..... geez

thanks guys.

 

[ezeke]

Re: rear of fuel pump dripping fuel

Call a BRP dealer and ask if she will get you repair kit# 438616 - it will have most of what you need. http://dealerlocator.evinrude.com/EN/?Rnd=1172157085156

Theoutdoorsman spent a bit of time documenting the rebuild of a similar pump that will be a help to you and others. You might want to print it as a guide for your rebuild.

I don't know why it did not make it to the Engine FAQ, but here is the link: http://forums.iboats.com/showthread.php?t=240864&highlight=438616