No oil pressure

[Ski in NC]

No problem with air in the sensing line. It will make the gauge respond slowly, sometimes very slowly. After firing up, watch the gauge closely. If needle lifts off the peg at all, pump is primed and it should continue to rise as the air in line compresses.

 

[catalinajack]

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.

Way too much overthinking here, IMHO. The engines ran with oil pressure two years ago. There is no reason to believe that the pumps on BOTH engines have failed while not being used. Getting an oil pressure reading while simply cranking the engine is highly unlikely. Think about it. Oil pressure gauges, whether mechanical or electrical, do not read out until an engine has been running for 1, 2, maybe 3 seconds at, generally, around 900 RPM. To expect an pressure reading at the relatively few RPM that the starter spins an engine is illogical. That is also why the oil pressure warning buzzer takes a few seconds to stop buzzing.

Angus99, you already pre-oiled the engine, a lot. Your starters are not happy with you. As for the necessity of pre-oiling, I am very skeptical. When dino oil is in the crankcase, all engines, gas or diesel, are being started "dry" after sitting for relatively short periods of time, perhaps as little as one week because all of the lubricant drains away. Remember, the old axiom, 90% of engine wear occurs at start-up. It cannot be escaped. Start those engines and go boating. And, if you are really worried about dry starts, use synthetic oil which leaves a coating on surfaces that does not drain down into the sump, if you think it is worth the extra cost.

 

[CaptSteve53]

If your engine has the external oil filters coupled by hoses, remove the in pressure hose to the filter and fill with a liter of oil to try and prime the pump, be very careful if you get it running and dont allow 2-3 minutes for the oil pressure to rise other wise you will be rebuilding as the cam shaft bearings and crank bearings will be toast even after 1 minute, here's a post below from the last guy that tried 1 minute with no oil pressure,

Just going through the same problem...My old 4 cyl Lehman.
I changed the oil cooler, filter and the filter bracket. Started it up and NO OIL PRESSURE...
I figured it was because the filter, oil cooler and the lines were empty so would need time to fill before I got any oil pressure readings.
I slackened the filter and there was plenty of oil, so I ran the engine for a minute at 1000 rpm waiting for the oil pressure to kick in....
Well guess what?
It didn’t kick in........
Now I have a main bearing job....Ship! Ship! Ship!
SO...
NO OIL PRESSURE... DO NOT RUN THE ENGINE...!
Hope this saves somebody a ship load of work!

Cheers Steve

 

[angus99]

Success (mostly)

Seems kind of superficial to be talking about boat issues with all-hell getting ready to be unleashed on Florida. I did want to thank everyone for their ideas. I removed about two quarts of oil from each crank case, injected a quart of fresh oil into each pressure switch port (using a cheap drum pump) and poured a quart into each valve cover filler.

Both engines started within two seconds and had good pressure in two to three seconds. no water leaks either!

Now I need to figure out why the starboard engine barely turns over on the house bank (1,250 amp hours and massive CCAs) but starts easily on the single Group 31 "start battery." And the port engine does exactly the opposite . . . cranking easily on the house bank and barely turning with the Group 31. I know for a fact all the connections and terminals are new and tight.

 

[TowLou]

Distance between banks and engines at all for cable length?

 

[what_barnacles]

N.m.

 

[stubones99]

Now I need to figure out why the starboard engine barely turns over on the house bank (1,250 amp hours and massive CCAs) but starts easily on the single Group 31 "start battery." And the port engine does exactly the opposite . . . cranking easily on the house bank and barely turning with the Group 31. I know for a fact all the connections and terminals are new and tight.

Put a clamp on ammeter on the starter cable and see how much power it's drawing. if the two starters draw similar power- amps, then take the starter to a rebuilder. Chances are one of the starter motor windings is open and not pulling it's weight.

 

[angus99]

Distance between banks and engines at all for cable length?

Distances are within about 6 ft of being equal. Cable is 2/0, new and sized for the distances. Nothing feels warm to the touch..

Put a clamp on ammeter on the starter cable and see how much power it's drawing. if the two starters draw similar power- amps, then take the starter to a rebuilder. Chances are one of the starter motor windings is open and not pulling it's weight.

I guess that would have to be both starters since they both struggle to turn over, but on different battery banks.

Thank you both.

 

[what_barnacles]

Ill change my n.m. to check for corrosion. Split the insulation and look at the wire. You can always paint it with liquid tape.

 

[angus99]

Ill change my n.m. to check for corrosion. Split the insulation and look at the wire. You can always paint it with liquid tape.

The wire is brand new.

 

[what_barnacles]

hmmm well maybe take the terminals off and hit them with a battery brush to make sure the lead is clean. Then maybe use a good ohm meter and measure the cables regardless of them being new. A poor crimp could be an issue. As well as a poor connection in a battery switch especially is it isnt rated for 2x the expected cranking current.

 

[stubones99]

Sometimes the commutators smear the copper across each section and that shorts the windings together which burns power and does not provide the torque since the extra winding being charged is too far away from the magnetic field.

You get the starters rebuilt which often involves undercutting the commutator, and that is simply taking a small saw and opening the gap between the contacts for each section. It is a simple thing to do, but you do have to take the starter off the engine and disassemble it to get to the commutator.

 

[alfamike]

"I know for a fact that connections are new & tight " - Famious last words

angus 99.

You said: --- I know for a fact all the connections and terminals are new and tight ---- new & tight does not mean good. Just means different.
----------------------------------------------------------------------------------

Now I need to figure out why the starboard engine barely turns over on the house bank (1,250 amp hours and massive CCAs) but starts easily on the single Group 31 "start battery." And the port engine does exactly the opposite . . . cranking easily on the house bank and barely turning with the Group 31. I know for a fact all the connections and terminals are new and tight.

------------------------------------------------------------------------------------

Well if I has a Boat Buck for every time I have heard that statement about boat electrical.


Ohm meter can some times help - but for the high current draw circuits involved here the ohm meter usually does not help you find the issue.

PLEASE, Do a "voltage drop test" on each circuit & you can narrow issue down to exactly what the issue or issues are.

Believe me, as an electrical guy, that if they work good on one battery & not on the other, something is wrong or something is different.

Since they are both working good - but on opposite batteries - then there is a starter, contacts or ground, return circuit or supply circuit or associated part or component or switch or connection or wire issue.

More diagnosis is needed.

There is an issue. Just need to find it.

Good luck.


Alfa Mike

 

[bglad]

I would go back and review how the grounding is cross connected since both starters work fine in a particular mode but fail in another. Positive connections are more easily tracked down visually but negatives block to block or between busses can be a little tougher to track down.

Seems kind of superficial to be talking about boat issues with all-hell getting ready to be unleashed on Florida. I did want to thank everyone for their ideas. I removed about two quarts of oil from each crank case, injected a quart of fresh oil into each pressure switch port (using a cheap drum pump) and poured a quart into each valve cover filler.

Both engines started within two seconds and had good pressure in two to three seconds. no water leaks either!

Now I need to figure out why the starboard engine barely turns over on the house bank (1,250 amp hours and massive CCAs) but starts easily on the single Group 31 "start battery." And the port engine does exactly the opposite . . . cranking easily on the house bank and barely turning with the Group 31. I know for a fact all the connections and terminals are new and tight.

 

[angus99]

Thanks, guys, I'll recheck all the connections--especially the grounds--and look into a voltage drop test.

Bill, we're wishing the best for you down there.

 

[Martin J]

Dirty terminal.

Apply battery discharge meter 5 min diagnosis.

 

[angus99]

Massive Red Face



The problem was I forgot I had disconnected the ground cable from the start battery to the common negative bus. It was laying over other cables and looked--at a casual glance--like it was still connected properly. Once connected, both engines spun effortlessly on the start bank.

Took her over to the fuel dock this afternoon and spent some money. We may go cruising tomorrow!!

 

[BruceK]

As long as it`s solved, all good. Happy cruising.

 

[TowLou]

Grounds yeah that would do it to.

 

[what_barnacles]

Ohm meter would have found that.

Glad you got it all squared away. Now take a minute and scold yourself and give the whole setup a once over for sanity's sake.