Mechanical fuel pump refurb - non Laverda

Dellortoman

Dellortoman

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Location
Tasmania, Australia
Bit of a long shot ?  I have an old fuel pump with a knackered diaphragm. Obviously not Laverda related but I thought some of the clever people on here might have some advice.

The pump is off a Volvo Penta boat engine, and spare parts seem to be pretty much unobtainable in Australia. Parts websites list the diaphragm as "discontinued".  So, I'm thinking I'll have to make a new one. What I need is the diaphragm material. It's 1mm thick and looks like some kind of cloth reinforced plastic or rubber membrane. Does anybody here know where I can find any such material? Or better still, does anybody have some that they could cut a small piece out of?
 
I used to have the website address of a place in England that would replace the rubber bit of the diaphragm in CV carbs. From memory one of the shop owners was in the Laverda World. That info I now don't have, anyone know this shop?
 
I found an Australian supplier of the diaphragm material, so I ordered a piece. It's not particularly cheap at around $3 per square inch, but better than buying an 8' x 4' sheet!  Now I just need to figure out how to disassemble the diaphragm and sandwich the new cloth in between the little metal plates.

In case anyone is interested, here's the mob that sells the material - They're called "Classic Carbs" https://classiccarbs.com.au/Carburettor-Fuel-Pump-Diaphragm-Nitrile-Sheet-1.5mm-thick-sold-per-Square-Inch-900.NDS1.5-
 
What model is it off Cam?
MD2 or 3?
Give "All Marine Spares" a call in Mona Vale Sydney.
They may be able to help
 
TC said:
What model is it off Cam?
MD2 or 3?
Give "All Marine Spares" a call in Mona Vale Sydney.
They may be able to help
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It's a 2003 (it's a 120? 3 cylinder, so there is a tenuous Laverda connection :D) but it uses the same fuel pump as all the MD series engines. There must be thousands of older boats in Australia with Volvo Penta engines that use that pump, so I dunno why the spares situation is so appalling. They only stopped making them 30 years ago.

Anyway, thanks for the tip. I'll give All Marine Spares a call.

PS - half an hour later ?  Just called them. No luck.

Also called Volvo Australia. They confirmed the part is no longer available, but they'd be happy to sell me a new engine.  ::)

Back to Plan A - make a new diaphragm.
 
Volvo Penta can be like that Cam, Ive had both MD and the later 3 cyl engines, fully rate the newer engines, better than Yanmah in my opinion, but parts can be a problem.
good luck with your diaphragm.....
 
Back to the fuel pump...  :D

I replaced the diaphragm on my old Gold Wing a couple of times. I just got the material from the local gasket shop.
Typical Honda, no parts available unless I bought the complete pump... but almost everything was repairable with standard parts!
 
Blimey, after a whole lot of on line research, and asking a parts supplier to unpack a diaphragm and measure it, I had a win.

Here's a tip for anyone who has a boat with an old Volvo Penta MD series or 2000 series engine. The fuel pump is made in Germany by Pierburg. They supply pumps to various engine manufacturers including VW. It turns out that the old air-cooled VW beetle engine from the 70's has a very similar pump that uses an identical diaphragm!

Here it is for sale in USA for $(US)21 from Wolfsburg West, a VW specialist http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113127141WW

It was the guy from Wolfsburg West who was kind enough to send me the attached photos, so I ordered two diaphragms from him. One to put in the spares box for next time.
 

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Maybe a urban myth.
A bloke was looking for a new piston for his English Royal Enfield, without success. Couldn?t find one anywhere...... took it into a car parts store, and a crusty old bloke there saw it and said it looked like a Holden grey motor piston to him.

Counter guy grabbed one, measured it and hey presto, exactly the same.

I can?t confirm or deny the facts, but may be feasible.

Cheers

Sick Man :D
 
There must be plenty of engines getting around with pistons adapted from something else. Pistons are reasonably un-complicated devices, basically just a round slug with a gudgeon pin through the middle. If it fits in the hole, you can probably make it work.

I have a TY350 Yamaha (old 2-stroke single cylinder trials bike) for which pistons are no longer available. If I ever need a new piston I'll be looking at using something out of another engine.
 
chrisk said:
Maybe a urban myth.
A bloke was looking for a new piston for his English Royal Enfield, without success. Couldn?t find one anywhere...... took it into a car parts store, and a crusty old bloke there saw it and said it looked like a Holden grey motor piston to him.

Counter guy grabbed one, measured it and hey presto, exactly the same.

I can?t confirm or deny the facts, but may be feasible.

Cheers

Sick Man :D
Click to expand...

A few years back I had a customer come to me and ask me to fit a Subaru piston to his B33 BSA engine. I have no idea why as B33 or Goldie pistons are available. All I had to do was rebush the rod for a larger gudgeon pin.

Diaphragms.  About 5 years ago I found I'd split the diaphragm on the oxy regulator of my gas welding set. I've been using it since I was a kid - it's the old man's set and probably dates to pre WW2. When I pulled it apart I found it had a home made diaphragm in it. About 3mm thick canvas reinforced rubber sheet.
So I did what the old man probably did and went to local mob Para Rubber who've been in business forever. $10 later I had a big enough piece of the identical stuff to make a replacement. And they had various thicknesses in stock too.
 
Well, there's more than one way to fix a knackered fuel pump.

The new pump diaphragms that I ordered from USA could take months to get here. Meanwhile summer is on the way and a want to use the boat. So I just replaced the flexible membrane on the old diaphragm. The nitrile material came from an ebay supplier.

Pump diaphragms usually aren't made to be taken apart, and this one is no exception. The end plate was held on by the end of the shaft being peened over. I had to machine the end off the shaft to get the old diaphragm off. But that left me with a shaft that was too short to reassemble. I thought about making a whole new shaft, but then had a better idea that was worth a try. I built the end up with weld metal and turned it back to the original diameter. Re-fitted the diaphragm plates with the new membrane between them and peened the built-up end of the shaft over again with a ball-pein hammer. It worked quite well. Diaphragm is held nice and tight on the shaft and the pump now pumps again.

 

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Top work, Cam! Serious welding is one of the few things I'm yet to master. I probably should buy a little MIG - I'm told they are pretty foolproof once you learn a few basic tricks.

I hope you're not hitting Bass Strait or the Southern Ocean on a day like today down on the Mexican end of the continent!
 
Piranha Brother 2 said:
Top work, Cam! Serious welding is one of the few things I'm yet to master. I probably should buy a little MIG - I'm told they are pretty foolproof once you learn a few basic tricks.
Click to expand...

Yes you should,  Bought my first mig middle last year and haven't looked back. Should have done it sooner.
 
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