No oil pressure

Our two Lehman 135s have been sitting up for two years. American Diesel recommends that before starting them I build oil pressure by holding the stop solenoid closed while someone at the helm turns the engine over. In 8 to 10 cranks of less than 5 seconds each, the starboard engine showed no pressure on the dash gauge. In subsequent attempts pressing the start button seemed to bump the starter and then disengage. (There is no hydro lock; I checked.) We tried the port engine but gave up after 6 or 7 times with no oil pressure showing. There were no bump/disengage episodes on port.

AD suggests putting a remote oil gauge on the block oil pressure port to rule out problems with the dash gauges. If there's still no pressure, they recommend removing the oil and "force lubricating" by injecting it back into the crankcase through the block port under external pressure.

My questions for the mechanically inclined on this forum:

- what are the most likely causes of no oil pressure? They ran fine previously and I changed oil just before the boat was put up. It looks pristine on the dipstick.

- are there any other ways to determine if the engines are building adequate pressure besides a remote gauge? (Nobody around here seems to have one.)

- any other tricks to building pressure in the block other than removing and injecting it back under pressure? If that's the only course, how much pressure should I use?

This has already consumed the better part of two days and probably most of my good will with the excellent folks at AD, so I am looking for additional input.

Many thanks.

I would start them and be ready to shut down if pressure doesn't build in a few seconds.

Another option would be to remove the injectors, or glow plugs if equipped, so the engine can be cranked over without compression.

Engine probably does not spin fast enough on starter to prime the oil pump. I don't recommend rolling with starter to build pressure for that reason. Either just start it or prime the oil gallery.

To prime the gallery, take an oil pressure switch or sender out and get a npt/hose barb fitting and a clean (!!) outboard squeeze bulb fuel line. Get a jug of warm oil (leave it in the sun) and pump a quart in. Put sender back in and fire it up.

Or just start it.

In my opinion, you either have 2 working oil pumps or you don't. I would let them start, blow the raw water out the exhaust and see if you get pressure. You have probably already primed them.

The starter issue is either a bad battery or bad connection. Check those first, always go for the simplest solution first.

Beat me to it Ski!

Oil Pressure -- where did it go ?

Oil Pressure - where did it go ?

The force lube oil inputted in to the oil galleries of the block is a really good idea.

How you do this is to go buy an inexpensive brake pressure bleeder tool.

You could borrow one from a mechanic friend, However, I recommend preferably using a brake pressure bleeder that has not had brake fluid in it,
So a new one is preferred, but be sure it is the type that has the rubber diaphragm bladder to separate the oil from the air pressure that pushes it, that is how I have done this in the past. Typically it has an air input valve with a Schrader valve in bottom & fluid fill on top & hose comes out top. Flexible Bladder rubber diaphragm in middle, I have used 10 to 15 PSI as a good start pressure. Fill top fluid chamber 50% full with the oil, Carefully Bleed air out of the top & seal that all up tight, then charge the bottom air chamber with air pressure after closing off the top. There is then a valve on top you can open & close to allow the flow of the fluid into the hose & into the engine. Make sure no air in the top fluid section for it spits & such. Need solid fluid oil flow. Not air as you already have air in there.

Very effective in getting oil flowing in the oil galleys as the oil pump in the engine may have lost it's prime.

Then after doing that, I would next go to Cranking the engine with no compression ( Remove Glow Plugs ) as next step because it is one of the best ways to get oil pressure with minimal damage as there is very little load on the bearings when you do this.

If no pressure after 30 seconds of cranking on a mechanical gauge which you can buy at any Napa Auto Parts store & after you have done these above steps if you have zero oil PSI then deeper look is needed.

Good Luck.

Alfa Mike

twistedtree said:

I would start them and be ready to shut down if pressure doesn't build in a few seconds.

Another option would be to remove the injectors, or glow plugs if equipped, so the engine can be cranked over without compression.

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I would do this.

I just started mine after 2 years on the hard. No problems.

It takes a good 10 seconds before my oil pressure will register. I have 2 120's and they both do the same.

Joe

Thanks, all.

I borrowed a remote oil pressure gauge and still get nothing spinning the starter. I'll try priming the gallery and then starting them with an eye on the prz gauge. Shouldn't be a problem getting warm oil today.

Stay tuned.

Followup

Interestingly, when I took the oil prz gauge off the block fitting after cranking it half a dozen times, oil came out in a small but steady stream. When I first took the sending unit off, that didn't happen. Does this mean the gallery is primed . . . Just not enough power from the starter to prime the oil pump?

Remember that cranking with no start can fill your exhaust with raw water which can flow back into the cylinders. Either get rid of the water or start the engines. Continuous cranking can do much damage. See the thread on unintended consequences!

Just a curiosity, are you sure there's power to the gauges when you crank. On my JD there's nothing until you release the start button. Don't know if that's by design or low voltage during cranking.

Ted

Xsbank said:

Remember that cranking with no start can fill your exhaust with raw water which can flow back into the cylinders. Either get rid of the water or start the engines. Continuous cranking can do much damage. See the thread on unintended consequences!

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Good thought. Seacocks are off and discharge water hoses are in a bucket.

O C Diver said:

Just a curiosity, are you sure there's power to the gauges when you crank. On my JD there's nothing until you release the start button. Don't know if that's by design or low voltage during cranking.

Ted

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Not sure, Ted, but I would guess if there is oil pressure it would show on the gauge when I release the start button. Pressure is supposed to build and hold for awhile, I'm told. Additionally, the remote gauge isn't powered and is also not reading any pressure.

Thank you both.

Toadhall said:

It takes a good 10 seconds before my oil pressure will register. I have 2 120's and they both do the same.

Joe

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Wow, that's a long time. Does it always do that? I'd guess it's something with the gauging system. I've never seen an engine where the oil pressure doesn't come up in 2-3 seconds, even after an oil change.

Id suggest just starting the engines.

It's much more likely you'll burn out a starter motor with all the cranking than an engine oil pump mysteriously failing while the engine was shut down.

twistedtree said:

Wow, that's a long time. Does it always do that? I'd guess it's something with the gauging system. I've never seen an engine where the oil pressure doesn't come up in 2-3 seconds, even after an oil change.

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I'd put mine at about 5 seconds before the buzzer shuts off.

Maybe I count really fast.

Seems Like my Yanmar was about the same

I'm not familiar with the Lehman, but the valve/cam components on some engines can be viewed through the oil filler hole (if no baffle). If there's fresh oil dribbling around the top end I believe it's safe to start. Alternatively remove the valve cover. But I wouldn't start an engine with an oil pump that's not known to be primed and immediately pumping oil to the bearings.

Curious how an oil pump, submerged in oil, can lose 'prime?'

Don't know about the Lehman, but the pump on the recently rebuilt engine in my Jaguar E-type is well above the oil level. Packed the gears in the pump with petroleum jelly for initial prestart pressurization of the oil gallery.

I went through this firing up Lehman 120's that had not been started for 3 years. I have mechanical gauges at the lower helm with 15 ft of tubing to the oil galley. They weren't registering anything while I was trying to start with fuel turned off. When turned the fuel on and fired the ,they showed pressure in 5 seconds. I did have a 5 second panic attack. I changed the oil before trying to start them.

I've seen this in cars too- starter won't turn the engine over fast enough to register on a gauge in the short bursts we usually give it. My455 Buick had me tearing my hair out until a mechanic friend said just start it. 5 seconds of no oil pressure before it read 70lbs on a mechanical gauge.

I'd fire it up and be prepared to shut it down if a mechanical gauge connected to the engine doesn't register. You say remote gauge- I assume that it is a mechanical gauge?

Yes, sorry, it's mechanical. I have the squeeze bulb and fittings but ran out of time and energy today. I will inject oil in tomorrow and watch the mechanical gauge when it fires up.

I do think some oil is getting moved around by the starter; just not enough to build significant pressure. As I noted above, when I took the mechanical gauge off this afternoon after cranking the starter, a small, steady steam of oil came out of the sensor port. That did not happen when I removed the sensor this morning and the only difference then was I hadn't cranked it.

Thanks.

The fact that it dribbled out some after cranking it over means the pump is beginning to prime.

Thanks to all who offered suggestions. I ran out of time this trip (well, that and a couple pitchers of pina coladas got in the way). Will inject oil and start the engines on my next visit to the boat.

The first piece of advice is as XS Guru states K.I.S.S.
Have you started the engine ? Is there fuel at the injector ?
Sometimes an engine left idle will on start up 'miss' on an injector due to a sticky spring, these usually clear themselves after running.
Some gauges are mechanical and some are electric, electrical ones register immediately, mechanical ones do not, they need the oil pressure to build (remember after 2 yrs the oil will be cold and thick, therefore even slower).
The starter will not turn the engine over fast enough to build significant pressure and if you continue you will eventually burn out the starter.
If it were my boat I would turn the engine over on the starter for 5 seconds(to pre-lubricate the engine after lying idle) I would then rest the starter for 10 seconds.
Open the throttles wide open(obviously out of gear) and then fire the engine up, the moments it fires IMMEDIATELY reduce the throttle setting to a fast idle.
Watch the oil gauges for 2/3 minutes and register the pressure.
If no pressure close down the engine and investigate further.
NOTE Lehman predominantly used Ford engines and on some of the very early models there was a 'cold start' button on the fuel pump, it was located at the bottom of the fuel shut off lever. RTTM.
To engage the 'cold start' feature on these engines, open the throttle wide, push in the button, it will locate with an audible click, start the engine and once it fires IMMEDIATELY reduce the throttle to a fast idle.
Have courage, be methodical and learn.

Did you run it after the oil change?

Maybe the oil filters are still filling up? Even pre filling the filter its tough to fill em all the way if they hang vertically.

My engines have electrical gauges, but I removed the sender on one and tried a mechanical gauge. It didn't register pressure either while spinning the starter (I no longer expect to see pressure with the starter alone).

I did run the engines for about 4-5 hours after changing the oil last time, with no problems.

I'll be away from the boat for a couple weeks but the next time I'm there I'll force-lube the galleys and just start them while monitoring closely.

Thanks.

If you did run the engines before then id not worry with oil pressure. Get them motors fired up one way or another if yoir boat is on the hard or in water. Dont rely on cranking them.

Also if a mechanical guage dont you need a physical line filled with oil to run from your motor to the gauge.

The mechanical gauge I used has a 3-4 ft hose and is easy to see from the lower helm when the hatch in the floor is removed.

TowLou said:

Also if a mechanical guage dont you need a physical line filled with oil to run from your motor to the gauge.

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The gauge will be accurate with air in the line, since the fluid pressure in a static line is equal everwhere. The air will, however, cause some damping of any transients.