Diesel Primer Bulb In Line?

[Delancey]

Any thoughts on including a primer bulb in line after the tank and before a Racor?

The mechanical lift pump on my engine will pull from the bottom of the pick-up tube in my fuel tank but will not get me up to where I would like to install my Racor filters.

I had the thought of putting a primer bulb in line but maybe less stuff to fail if I skip it and just rely on the manual pump within the Racor?

Thanks!

[GordMay]

➥ http://www.cruisersforum.com/forums/...ork-47848.html

➥ Squeeze Bulb Priming on Diesel Powered Boats

[Delancey]

Thanks Gord. You're the best!

[zeehag]

i chose to add a low pressure electric assist pump after the racors to prime engine. there is way too much potential in real time living for the bulb to leak air into the fuel line. ask me how i know and learned these lil things...

[Delancey]

Yes, of course nothing electric ever failed on a boat including lift pumps.

[jimbunyard]

Have one on mine, and enough length of hose to bypass it if fails...

[zeehag]

Originally Posted by Delancey

Yes, of course nothing electric ever failed on a boat including lift pumps.

the lift pump on Ka Lunk is MANUAL. not electric.
the electric assist low pressure pump is just exactly that... electric assist. and spares in bin.. rodlmffao. you dont think that with the problems i have experienced with this engine in this boat that i woud rely on either or, not have both???
oops.
forgive me for not having given the exam after my ka lunk experience so you could learn that.....
and now i have not just one but 2 RACORS 500 series, so i can rule the world. i wanted 300s, as those are perfect for the flow rate for my engine, but they are not available,,, even at marine swapmeets out in cruiseland, so i had to make do with the larger 500s.
rodl.
more leak potential but worth it, as i refuse to allow water into this yes it is new engine. all parts are new except only 4. makes it new. fewer than 50 hours on it, makes it new.
however each racor 500 holdls around an extra pint to liter of fuel, so one adds it first to filter then pumps thru to prime.
i have watched so many allegedly intelligent males try to prime empty liter sized filters by hand.
hay guys, that dont work. electric assist does. is easier to fill a pint sized filteration cannister using a bottle of fuel then electrically pump the air out . there are many feet of fuel line to clear--why not use a method that is simple, and easy to replace when fail happens. in 3000 miles of use with this boat, i have had to change out the electric pump i bought at napa and or autozone one time. i buy spares so fail is irrelevant. if boat battery is that low as to make or cause fail of elect assist pump, you are going no where anyway, so is moot.

[transmitterdan]

Originally Posted by Delancey

Yes, of course nothing electric ever failed on a boat including lift pumps.

An small electric fuel pump is generally designed to "fail safe" so it will not block the flow of fuel. The pump Zee recommends is better than a bulb pump IMO because they are less likely to become a source of air. They are cheap too.

[Delancey]

Originally Posted by zeehag

i chose to add a low pressure ELECTRIC assist pump after the racors to prime engine.

?????

[Delancey]

Originally Posted by transmitterdan

An small electric fuel pump is generally designed to "fail safe" so it will not block the flow of fuel. The pump Zee recommends is better than a bulb pump IMO because they are less likely to become a source of air. They are cheap too.

One of the links Gord provided suggest substituting the cheap crimp-style hose clamps on the primer bulb for normal ones to prevent air ingress. If these pumps are fail safe why do people install or carry back-ups?

[zeehag]

when your boat is coming off anchor using engine dependent electric windlass and freeking mechanical fail happens with rocks within 60 yards on a lee shore surfline anchorage, you WILL dream of the electric assist pump, i PROMISE... quick use the jib n get the flock outta there while you simultaneously bleed system?? i think not. btdt, hated it. learned my lesson. no i didnt even come within 30 yds of those mexican jumping rocks. anchor came up as i sailed off. anchor was almost belayed, but for the last 10 ft...
this happpened within 20 min of ignition on. was fuel pick up fail that time.
.. had a crew with half a brain. ..only half....
i am smart.
the normal kind of hose clamps do not cure that air leakage problem, i learned ... i bought the electric assist pumps after i found the fail in that systemless. the bulb type outboard hoses are great for priming hoses for siphoning fuel from jerry jugs on deck into tank fro use..

[sartorst]

An electric pump prior to a manual pump is a bad idea! WHEN the manual pump diaphragm fails the electric pump will continue to pump fuel into the crankcase !! If it is on only when priming the filter it would be OK

[Kenomac]

I was going to add one last season, but decided against it. I still have the bulb in case I need it someday. Our Yanmar has a primer pump on top if it became necessary to prime the system, but when I installed the double Racor filters with crossover lever, I was surprised at how much air could be swept up into the engine with no effect.

Plus, I agree with Zee, it just looked like an ideal spot for a potential leak in the system (if that's what she said). At one point, I did have the bulb installed, but the more I thought about it.... it just seemed like I was adding the weakest link into a rather robust system with double clamps etc.

[transmitterdan]

Originally Posted by Delancey

One of the links Gord provided suggest substituting the cheap crimp-style hose clamps on the primer bulb for normal ones to prevent air ingress. If these pumps are fail safe why do people install or carry back-ups?

Fail-safe means that if the electric pump fails it does not stop the normal flow created by the engine lift pump. In that sense it is similar to the bulb pump.

You can use the primer bulb if you want but the electric pump is better, easier and less likely to leak fuel out or air in. A flick of the switch will also create an emergency backup to the engine lift pump when it inevitably fails. As someone else pointed out the electric pump will put diesel into the crankcase of some engines if the engine lift pump diaphragm fails. This is easy to see by the rising oil level on the dip stick. Bypassing the failed engine lift pump with some hose and fittings will get the engine running again with the electric pump.

[Captain Bill]

My Endeavourcat came with squeeze bulbs 13.5 years ago. They have never beenn changed and are still flexible. After I fill my Racors and change the the engine filter I do an initial system air purge using the bulb. When I hear a steady stream of fuel returning to the tank, I do a final purge using the yanmar manual pump lever and the air bleed screw. I have never gotten more than two small bubbles out of the bleed screw using this proceedure. I have had many things stop my engines over the years, but never anything associated with the bulbs. Since they are never in sunlight they don't seem to deteriorate the way outboad bulbs tend to. Just in case I do keep spares on board. I think concerns over air leaks are overblown. I don't think they are any worse than any other type of pump one might use in the same location. The other nice thing is that there are no electrical parts to fail.