Topic: Oliver 6 HP fuel pump help needed – Antique Outboard Motor Club,Inc

This topic has 14 replies, 9 voices, and was last updated 10 months, 1 week ago by huntleybill.

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January 20, 2024 at 5:19 pm #284169
huntleybill
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Motor runs good but the fuel pump isn’t pumping. I replaced the diaphragm (which was rock hard and cracked) and cleaned the pump. I replaced it and still it will not pump. It occasionally spits a little but that is it. It IS getting pulses from the power head. Are there replacement pumps for these? Kits? Or is there something I am doing wrong?

Your help would be appreciated. Thank you

Bill
January 20, 2024 at 5:36 pm #284173
seakaye12
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That sure looks simple; eh? Not even any check-valves? Perhaps there is a separate check-valve in the line or tank?

Perhaps trying to “prime” it a bit would help?

Hopefully someone with experience on these will have some remedy. Otherwise it looks very similar in overall size and fitment to one of the modern Mikuni pumps.

Note in the text of Discount Marine’s sale page for this rebuild kit where he mentions that a check-valve has been added?

https://www.dicarbparts.com/home/176-perkins-45-hp-outboard-carburetor-withtescher-vl4-diaphragm-tillotson-hc10a-di-23853.html
January 20, 2024 at 9:46 pm #284183
Buccaneer
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Bill, I think Chuck is correct about the check valve. I believe it was originally
in the Oliver hose. I didn’t have an Oliver tank, and I didn’t know this
about the check valve seven years ago when I fixed mine up,
I also put a new diaphragm in the original fuel pump, but couldn’t
not get it to work either.
I then tried a gravity tank, and got the motor running fine.
I thought I might have had low crankcase pressure, so back on the rack it
went for six years. Finally decided to have another look, and ended up
putting on a B&S pump (with check valves built in) and it ran great.

UPDATE, in looking further at my Notes, I didn’t get the B&S pump to
work either, until I replaced a bad o-ring in the reed block, and
changed out the Sears gas hose quick coupler that I suspected of
sucking air.

Prepare to be boarded!
January 20, 2024 at 10:09 pm #284184
huntleybill
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Thanks Buccaneer.

Would you happen to have the part number or a link to the pump you used? I replaced the fuel lines as the were very brittle. Also, the gas tank hose connection on this motor is just a hose barb. In an effort to test the running condition of the motor, I just took the connector off my Johnson single line gas tank and there is n0 check ball in any of the fuel lines. I don’t have an Oliver tank either. So, if you have a part number or a link to one that will fit, I’d appreciate that.

Thank you so much

Bill
January 21, 2024 at 9:48 am #284188
Buccaneer
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808492 is the B&S pump I used on my 5.5 hp Fisherman, and
I believe the same one on my Oliver.

Prepare to be boarded!
January 21, 2024 at 10:52 am #284191
frankr
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Several years ago I studied the Oliver fuel pump till my brain hurt. Still hurts but I think the check valves are the holes and diaphragm in the slots at the ends. Think outside the box. The diaphragm probably has to be just right in thickness and stiffness. That’s all I remember just now.
January 21, 2024 at 11:01 am #284192
joecb
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Maybe your new diaphragm rubber is too taut over the vacuum cavity such that there is insufficient “stroke” . Can you try preforming a bit of a pocket before assembling? Maybe use the pump housing as a form tool with a small ball shaped “lump”… a little heat too, might help.

Joe B
January 21, 2024 at 11:49 am #284193
huntleybill
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Thanks Frank, I used diaphragm materiel but I don’t know what thickness the material should be for this application. I don’t think I can use the old one as reference as it is dried out and cracked. I’m going to order the pump Buccaneer suggested and save this one for future experimentation.
January 23, 2024 at 10:26 am #284267
seakaye12
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frankr wrote:

Several years ago I studied the Oliver fuel pump till my brain hurt. Still hurts but I think the check valves are the holes and diaphragm in the slots at the ends. Think outside the box. The diaphragm probably has to be just right in thickness and stiffness. That’s all I remember just now.

Frank….maybe reading the text of the patent is what made your head hurt? Somewhere amongst all that….there might be an explanation of how it works. Maybe..

https://patents.google.com/patent/US2598147A/en
January 23, 2024 at 5:40 pm #284270
geary
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Bill, Do yourself a favor and throw the original pump away ! These pumps work great on almost any two stroke engine and are reasonable priced ! Keep the Blue Smoke flowing !

Geary

https://www.ebay.com/itm/382615423775?hash=item5915a80b1f:g:6dAAAOSwkCBc6s4v
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