Topic: 1989 Johnson new OMC 9.9 fuel pump pn 0397839

This topic has 11 replies, 6 voices, and was last updated 7 years, 7 months ago by fleetwin.

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August 28, 2016 at 12:50 am #5083
PugetSoundBoater
Participant
i REPLACED this pump with zip ties on both fuel lines ,got them real tight. Squeezed the tank line primer bulb, no leak. fired it up and noticed a drip off the lowest corner of the pump metal base. i redid the fuel outlet zipties with 2 this time. still got wet .
I wiped the pump off real good and wrapped a paper towel rolled up and twisted like a rope and wrapped it around the pump body at the fuel outlet.
I then noticed a fine spray of fuel intermittently coming from the 1mm x 1mm square hole on the black plastic plate next to the metal base .
i’m sure it is coming from that hole and not the fuel outlet as i had the towel wrapped around the outlet and would have blocked any spray.
What are these "vent holes" for ? Could i plug the hole up or try to return it for a replacement.Will send a photo to Mumbles and Fleetwin shortly of the section of concern of a used pump for reference. EDIT for clarification

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
August 28, 2016 at 1:29 am #42793
johnyrude200
Participant
Was this a new, used, or rebuilt pump? If it wasn’t new, than there is a gasket failed internally or components are misconfigured. There shouldn’t be fuel coming out of those holes. they need to be facing DOWN too.

Of course, I suppose a gasket could have failed on a new pump too. It’s just fiber material and the plastic diaphragm inside. Plus a couple of small springs with plastic cups to protect the gaskets/diaphragm. Don’t be afraid to pull it apart and rebuild it, just use the rebuild instructions.
August 28, 2016 at 1:34 am #42795
wedgie
Participant
http://www.leeroysramblings.com/Rebuilding_fuelpump.htm
August 28, 2016 at 1:49 am #42798
fisherman6
Participant
US Member - 2 Years
I agree with JohnnyRude, do not be afraid to pull the pump apart and rebuild it. I will reiterate to follow the instructions to the letter though. Pay close attention to detail and don’t lose the little springs and caps. It’s a little confusing the first time or two.
-Ben

OldJohnnyRude on YouTube
August 28, 2016 at 1:54 am #42799
PugetSoundBoater
Participant
this is a new pump. i have not taken apart and will call the reputable online seller Monday. I should not have to rebuild a new pump at $68 .Just wondering if those holes are for the atmospheric pressure to allow the diaphragms to move freely.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
August 28, 2016 at 2:02 am #42800
johnyrude200
Participant
before you send it back, make sure ALL 4 screws are tight. If either or both of the two smaller screws (not the ones that bolt it to the motor, a.k.a. the longer ones) are loose, than that could cause a fuel leak from any number of areas.
August 28, 2016 at 2:08 am #42801
PugetSoundBoater
Participant
I did check and tightened the 2 short screws a bit They are plenty tight.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
August 28, 2016 at 2:30 am #42807
fleetwin
Participant
US Member - 2 Years
OK, here are the photos:

OK, well it looks like that slot is an atmospheric vent to allow free movement of the diaphragm…But, I will freely admit, I have never successfully rebuilt one of these little pumps, my vision is too bad, hands too shaky, to ever get those little pieces back together properly again….Someday I will conquer one of these little buggers!
In any event, I would certainly contact the seller if you paid $68 for this leaky pump! He should refund your money, or at least give a partial refund if you successfully rebuild this thing.
August 28, 2016 at 3:28 am #42811
Mumbles
Participant
I don’t think it’s new.

What’s that rust or crud around the check valves? 😮

The outer cover on these pumps tend to warp causing a leak but they can be straightened out by lapping them with some fine wet n dry paper on a piece of plate glass.
August 28, 2016 at 3:38 am #42813
PugetSoundBoater
Participant
MUmbles, the photo is of the old dissasembled pump , for reference to where the problem is. Sorry if I didn’t clearly state that. I’ll call the retail online seller Monday. Thanks.

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson
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