Primer bulb on Yanmar Diesel

[Cheechako]

I would check you tank vents.
Also, I have found SOME bulbs get very soft and may even be deteriorating and sloughing black 'powder like' debris from diesel effecting the rubber.

I had a grey colored one that didnt do that but a black one did. I suppose if it's too bad and spongy soft it might collapse, but a sailboat diesel sucks so little I wonder.....

An inexpensive electric pump is a good solution in lieu of a bulb, the pump works much faster when changing filters etc.

[bact0ee]

Originally Posted by Snore

Check racor, it is likely clogged. High ROM needs more fuel, racor cannot supply, injector pump pulls vacuum, bulb collapses. When you see it you assum blurb, but real fault is clogged filter, or other impediment to fuel flow.


PS I HATE primer bulbs below deck! Spend $100 and wire in a lift pump. It should turn on with ignition. This will also make changing filter much easier.

I have had fuel issue in the past. The boat spent much time in the Bahamas before my purchase. I have the fuel professionally polished three times with the first two times finding junk in the polisher filters.

The last time I added two inspection ports to look into the tanks and then polished again. Also just replaced the fuel line from the bulb to the tank and cleaned the Racor.
The pickup tube does not have a screen although I don't know about a check ball.

So I am leaning toward the vent being a problem. At one point the fuel polisher reccomended adding a clam shell over the vent to keep water out which I did. I was once told that I could open the fill cap and that would act as a vent.

Oh, In the past I have done what was mentioned and that is pull off the fuel line at the bulb and blow into the tank to push the obsticle back into the tank. The most recent bulb collapse the blow was very easy like I was only blowing the fuel out of the tube.

Many thanks for the help.

[c.K.]

Originally Posted by Snore

Check racor, it is likely clogged. High ROM needs more fuel, racor cannot supply, injector pump pulls vacuum, bulb collapses. When you see it you assum blurb, but real fault is clogged filter, or other impediment to fuel flow.


PS I HATE primer bulbs below deck! Spend $100 and wire in a lift pump. It should turn on with ignition. This will also make changing filter much easier.

I totally agree with this answer

[stormalong]

Originally Posted by Snore

Check racor, it is likely clogged. High ROM needs more fuel, racor cannot supply, injector pump pulls vacuum, bulb collapses. When you see it you assum blurb, but real fault is clogged filter, or other impediment to fuel flow.


PS I HATE primer bulbs below deck! Spend $100 and wire in a lift pump. It should turn on with ignition. This will also make changing filter much easier.

Originally Posted by c.K.

I totally agree with this answer

Snore and c.K, Do you have any actual experience with primer bulbs or is this your opinion?

[donradcliffe]

Originally Posted by stormalong

Snore and c.K, Do you have any actual experience with primer bulbs or is this your opinion?

I have used primer bulbs for years, and I carry one in my boat delivery kit. They work well for diagnosing fuel issues. However, I have never left one permanently connected because they can make a small fire into a large one.

[reflectionsv37]

I've had a bulb on my fuel line between the tank and the racor for 25 years. Makes it very easy to top the racor up with fuel after a filter change and removing any sediment/water from the racor from the drain at the bottom of the racor.

I had the exact same problem once. The obstruction is likely at the fuel pickup location. I flipped the bulb around, gave it a few good pumps and could "feel" the blockage clear. Everything worked fine after. Just remember to flip it back to the proper position when you're done. Might also consider having your fuel polished to clean any gunk or debris from the bottom of the tank. The filler inlet on my tank sits directly above the tank. Every couple of years i use a primer bulb connected to small diameter piece of rigid PVC pipe that will reach down to the low point of the tank to pump out anything that might be at the bottom of the tank, below the pickup point. I was shocked by what I pumped out the first time.

[Talbot]

Lots of good advice. However, I have had a primer bulb collapse on me in the past.
I am slowly replacing all mine with new racor filter that has its own priming pump - Racor 215R10 diesel spin on fuel filter.

[c.K.]

Originally Posted by bact0ee

I have a primer bulb on my Yanmar diesel (54 hp) and after about a hour or so it will collapse when running at 2500 rpm. When it collapses it shuts off the fuel and the engine dies. I recently tried running at 2000 rpm and the problem went away.

Has the bulb wore out to where it cannot handle the suction at this rpm or is there another culprit.

Appreciate any thoughts. Thinking of removing this bulb from the system. It is between the fuel tank and the racor.

May be a late reply, if that primer bulb collapses at higher rpm your fuel filter needs to be replaced the engine draws more fuel than the restricted filter can pass and the bulb collapses

[sailcrazy]

Thebulb should be free-flow when it's not being pumped...the collapsed bulb shows either a failed bulb checkvalve, or, more likely, a significant suction in your fuel line under higher demand. Could be the filter, or the tank vent, or the pickup...all have been suggested. But there is a reason for the flat bulb! I installed bulbs on both our Yanmar 4JH-TE (55hp), and our genset. I've since switched the bulbs out for a NAPA 12vDC fuel pump (under $50)...it's small and simple, and free flowing when unpowered. But when powered does a great job of priming/pressurizing the fuel system before start, or getting the air out after a filter change. I put each of ours on a toggle switch-they've worked perfectly now for 10+ years!

[Davwu]

Sounds like tank vent clogged or something in the pickup line in the tank, so may be time to drain and flush the tank. Surveyor told me I wasn’t allowed to have a primer bulb in the engine room. Not so sure about that, but bought a spin on primary filter housing with a primer pump built in. Works great and makes filter changes and bleeding really easy.

[nofacey]

The primer bulb is a handy way to refill the Racor after a filter change, and get fuel to the lift pump if the fuel tank is buried deep below the engine.
- personally I install an electric feed pump (with bypass valves) ahead of the Racor - it let’s me pre-prime everything except the hp side after any fuel system work, backs up the engine mounted lift pump in case of failure AND if the engine quits in dire straights, gets you running right away, letting you get out of trouble before having to change filters/find leaky fuel line joint etc. Simply put, it gets you out of trouble.

Having said all that, I agree with the majority - you have a fuel flow restriction on the tank side of the Racor. Check the tank air vent first, then the inlet to the primer bulb, then the pick up in the tank.

[harbin2]

My vote is for a clogged vent or tank pickup. The clog must be upstream of the bulb to create a vacuum in the bulb, making it collapse. A bulb was recommended to me by a mechanic almost 20 years and two boats ago. I was skeptical at first but the first boat had problems with air in the fuel and it was real nice to have the bulb to get the engine running quickly again. Those little lift pump levers seemed very ineffective. So, now I just keep one installed - mainly helpful for fuel filter changes since my current engine is pretty (air) leak tight.

[Snore]

Originally Posted by stormalong

Snore and c.K, Do you have any actual experience with primer bulbs or is this your opinion?

It was expressed as an opiníon.

Delivered a vessel with primer bulbs and didn’t like it. Primer bulbs are now a checklist item for me. If the boat has primer bulbs, I don’t move it. Why?

Consider the all thickness of fuel hose versus a primer bulb. The extremely thin wall thickness of a primer bulb makes me uncomfortable. If you like them- Great!

I don’t like them, this is my opinion, and it has cost me money….

[harbin2]

Hi Snore
Thanks for sharing your opinion. It's making me re-think mine. I know there are are strict standards for fuel lines and I know they are definitely much thicker than my priming bulb. I bet it wouldn't pass a survey. And that's not an opinion. Anyway, thanks.

[OneBoatman]

A priming bulb is not a necessary part of the system. Diesels typically have a mechanical lift pump with some also having an electric lift pump. You have one or more of three possible problems: A kink in your fuel line, your fuel pick up is clogged with bacteria, or your fuel/water separators filter is needs changing. Such restriction is starving the engine of fuel. Once resolved, you will need to bleed the fuel system if it the system not self-priming. My guess would be the second one, of which it is not uncommon for this blockage to be intermittent when it first begins.