My primer bulb has gone really soft (opposite of what petrol does - hardens). Too soft for comfort, nearly mushy soft.
I know diesel oil can be aggressive in it's own way. I know I can use another petrol bulb and replace when it goes off but I'd rather not; who knows when it may release tiny particles into my injectors.

So looking for a replacement - preferably a brand of primer bulb that is manufactured to handle diesel. There are diesel outboard motors around so you would think they would need purpose made primer bulbs. Any ideas?

Maybe these?
Description says OK for petrol, petrol/ethanol and diesel fuels.

Some Nissan diesels have bulb primers that might work
patrolapart.com.au/product/genuine-nissan-patrol-gu-y61-lift-pump-bulb-for-zd30-cr

Have you thought about moving away from bulb type? There's plenty of other manual or electric options.

Could you install one of these bulbs in the return line so when you change filters you don't have to crack injectors?

Just buy a metal 12v fuel pump. They are cheaper and when used with a jumper lead run for as long as you like. You can run the pump and have both hands free to bleed the engine opening the vents or cracking an injector line. When started, disconnect the 12v power till next time.

Yep like Ramona said. If I didn't have gravity feed I would be using an electric lift pump to prime with

I just bought another one of these. Don't buy the square ones they seem to leak a bit and the noise is annoying.

www.ebay.com.au/itm/12-Volt-Petrol-Diesel-Gas-Fuel-Pump-Universal-Inline-Electric-Pump-HEP-02A/224085467759?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20201210111314%26meid%3De8949b2f17154536b2b6ac2c8b55208a%26pid%3D101195%26rk%3D1%26rkt%3D12%26mehot%3Dco%26sd%3D124265200370%26itm%3D224085467759%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseUnbiasedWeb%26brand%3DUnbranded&_trksid=p2047675.c101195.m1851

Yep, I concur with Ramona. I fitted one, magic.

Thanks for the suggestions, guys.

As far as the electric pump goes, I have one of those somewhere in a draw to use for portable fuel polishing.

But really, for the engine I prefer to keep it as simple as I can (would love to start it without battery, but I don't think I have the muscle mass required). Besides, I like the feel of the pressure building up when using the bulb. It builds up but never goes fully hard as for an outboard; so if the pressure ramp-up changes one day I'll take that as a cue that something's changed.

That Nissan bulb posted by Wander really looks the part, though a bit pricey (seems like RRP is $180 though discounted to $80). Interestingly, the text accompanying that bulb suggests it be placed between fuel tank and fuel filter.

In contrast, I placed my bulb to "suck" the diesel through the coarse filter rather than "push" it as they suggest. But then, you'd think Nissan would know best since it's their day job.

i always use the engine lift pump to prime so that the integrity of the fuel delivery system can be determined..

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Jolene said..
i always use the engine lift pump to prime so that the integrity of the fuel delivery system can be determined..

On my Yanmar sometimes when the engine stoppes, the internal cam that operates the lift pump would be pushing on the mechanism to operate the pump. This would limit the use of the external lever as the internal diaphragm was already depressed. I would need to turn the over to get it in another position so I could get full use of the external lever on the lift pump. Not really a problem if you are aware of it. But does explain why it might take so long to try and bleed the lines when using the manual lift pump lever and make you think you need something better.

On a marine diesel the flywheel is right in front of you. So when your hand pumping and you don't feel the the cam on the pump just rotate the flywheel till you do. On converted cement mixer motors just fit an electric pump to prime. If your going to use a fuel bulb fit it in the same place in the hose as in outboards, close as possible to the tank.

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Ramona said..
If your going to use a fuel bulb fit it in the same place in the hose as in outboards, close as possible to the tank.

This advice is pretty clear, but could you add a few words to explain the benefit of that location, just so we learn something?

In the absence of a primer bulb, the built-in lift pump will be "sucking" the diesel through the coarse filter, so what is the drawback of the bulb doing the same?

Some pumps suck but most prefer to push. The diaphragm pumps like in a lift pump will lift or suck even when dry. Rotary pumps like to be primed. I have no idea what is inside of a squeeze bulb but they are always close to the tank and as low as possible. If you mount a bulb in the bottom of a loop in your engine bay so that it stays primed at all times it will work. Same goes for the $15 12v rotary diesel pump, mount it in the bottom of a loop.

When priming a pump we must understand that it is atmospheric pressure that supplies the flow to the pump.
The pump displaces fluid which creates a low pressure in the suction line. Atmospheric pressure then acts apon the surface on the fluid in the tank and forces it into the suction line to balance to atmospheric pressure.
A squeeze bulb just like any other diaphragm pump, relys on atmospheric pressure to force liquid into it to regain its full shape but if too much pressure is lost due to resistance in the suction line, the atmosphere will crush the squeeze bulb until atmospheric pressure can fill the bulb assisted by the ever so slightly low pressure created by the bulb trying to return to it's original shape.
Basically the longer the suction line,,, the higher the losses,, one of the reason why suction lines are usually larger in diameter.

Just to clarify, engine operated diaphragm lift pumps usually have a spring that helps the diaphragm maintain a lower than atmospheric pressure whilst it return's it to shape.

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Karsten said..
My primer bulb has gone really soft (opposite of what petrol does - hardens). Too soft for comfort, nearly mushy soft.
I know diesel oil can be aggressive in it's own way. I know I can use another petrol bulb and replace when it goes off but I'd rather not; who knows when it may release tiny particles into my injectors.

So looking for a replacement - preferably a brand of primer bulb that is manufactured to handle diesel. There are diesel outboard motors around so you would think they would need purpose made primer bulbs. Any ideas?

why not change to a pump and filter like this ?
www.ebay.com.au/itm/For-Toyota-Landcruiser-HZJ70-HZJ75-Series-Primer-Pump-and-Fuel-Filter-Ryco/313063557444

Having replaced my engine about 18months ago now with a Beta 10 can I ask is it the norm to turn off the diesel at the tap after use or leave the tap on allways. I have tended to leave it on to avoid the issues of air blocks in the line as I think I was told its a pain to bleed them. I have a substantial fuel tap install and well secured so unlikely to burst however I do understand nothing is 100% guaranteed.

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MrMac said..
Having replaced my engine about 18months ago now with a Beta 10 can I ask is it the norm to turn off the diesel at the tap after use or leave the tap on allways. I have tended to leave it on to avoid the issues of air blocks in the line as I think I was told its a pain to bleed them. I have a substantial fuel tap install and well secured so unlikely to burst however I do understand nothing is 100% guaranteed.

I leave fuel always on.

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Jolene said..
When priming a pump ......Basically the longer the suction line,,, the higher the losses,, one of the reason why suction lines are usually larger in diameter.

Thanks Jolene, good elucidation.
Your latter point about suction line length vs resistance may also be a good reason to have the primer bulb as close to the tank as possible. Learn something every day.

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Harb said..
why not change to a pump and filter like this ?

Thanks Harb, nice idea, fewer parts, fewer junctions, fewer leaks. Though not clear whether, for that style of filter, you can see and then drain residual water.

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MrMac said..
Having replaced my engine about 18months ago now with a Beta 10 can I ask is it the norm to turn off the diesel at the tap after use or leave the tap on allways. I have tended to leave it on to avoid the issues of air blocks in the line as I think I was told its a pain to bleed them. I have a substantial fuel tap install and well secured so unlikely to burst however I do understand nothing is 100% guaranteed.

MrMac, I would prefer to leave my tap on for precisely that reason - a leak in the system would draw down the fuel in the line and draw air in, so you might have to bleed the system every time you'd turn it on. For me, bleeding is awkward because I'd have to remove the steps and cowling to get to the engine (my new removable panel could make it much easier). And I'm lazy, and don't like the extra work to turn the engine on.

However, I've got a leak at the tank (different from the leak at the engine), which will empty the fuel tank into the cockpit locker over the course of a week or two. I think I know how to fix it by re-routing the fuel lines. Until I do, I'll have to turn off the tap at the tank.

So, if you don't have a leak, leave the tap on. If you do have a leak, fix the leak.