Oil pressure sender fitting broke off.

[Scott Danforth]

agreed, a GL is a carbureted motor. only thing sophisticated on it is the electronic ignition module.

 

[GeorgeDes]

So the GL has just the one oil pressure sender to deal with? Sounds like it would be the same with the temperature senders as well. The GSI has a total of four senders and the ECM senders are not the same configurations as the ones that feed the dash gauges. The only ones easy to access are the temperature senders.

 

[Mi_fiveo]

I’ve seen several posts with the same issue. Start the engine and have 40psi at idle on the gauge. Stays consistent and seems good to go. Run the boat on plane and when you come down and drop it into idle, then the gauge starts showing low oil pressure less than 10 and the alarm goes off. Only seems to do it when the engine is hot and after running under a load. If you bump the throttle up just a bit the pressure returns and the alarm stops. From other threads I’ve read, it seems too much oil may also be the culprit.

 

[GeorgeDes]

Have you hooked in a mechanical gauge yet? Harbor Frieght

 

[GeorgeDes]

HR sells a cheap set that comes with multiple fittings so you can easily tee it in along side the sender so you can compare your gauge readings with the mechanical readings. The dash gauge reading as well as the telltale depend upon electrical resistance through the connecting wire so if the wire or connections are faulty you will get a false reading and perhaps the telltale warning.

 

[Mi_fiveo]

Went to the auto parts store and found some similar fittings. Came home and there is a box from fedex with the Volvo Penta parts. Installed everything and fired it up. Reads a steady touch below 40psi at idle. I grounded the wire out to test the gauge and it spiked to 80psi and stayed there. I’m going to raise the front of my boat because that’s how it sits in the water and verify oil level on the dipstick. Next time I get out on the water I’ll run it hard and see if the pressure still drops at idle. If it does I’ll run a new wire to the gauge and try a mechanical gauge at the fitting to see what it reads. Process of elimination I guess.

 

[GA_Boater]

Are you saying when the bow is down that you have the low oil pressure? How much oil is in the motor?

Something tells me it's either low on oil or the oil pump pickup isn't picking up with a low bow.

 

[Mi_fiveo]

No, that’s not what I meant. I have a Starcraft Islander and the bow sits way up in the air. I checked and changed my oil with the boat level on the trailer. I thought maybe with the bow raised up in the water, the oil would be too full and maybe contributing to my problem. I checked oil level with the bow raised up like it would be in the water and it was about 3/4 of the way up the dipstick, just under the full mark. Guess that wasn’t it.

 

[GeorgeDes]

Went through a very similar process of elimination. My problem first showed up when I had the boat on muffs and it was in a maintenance rack with the bow tilted up. I at first attributed the oil pressure warning to this. It went away for a while after I splashed the boat then showed up again. Oil level was fine so my first reaction was I had bearing issues or a bad oil pump or some other catastrophic engine issue. An oil analysis helped put that some of that panic attack to rest. Then the real process of elimination started and eventually tracked to something very simple!

 

[Mi_fiveo]

[No message]

 

[Mi_fiveo]

George, I’ll definitely try your suggestion to run a new wire if the problem persists. I want to eliminate this problem and make sure it isn’t an issue with the engine. I kind of doubt it is, my engine has about 500 hours on it and seems to have been well maintained.

 

[GeorgeDes]

Let is know how it works out. As you pointed out lots of people posting here have been chasing oil pressure issues. So far, most of the ones I have read about were not catastrophic engine issues

 

[Mi_fiveo]

I really wonder if this has anything to do with my problem. Several times I have noticed my oil dipstick has popped out quite a bit after running the boat on plane. With the dipstick hanging out, would that cause low oil pressure at idle? No idea what is causing this. I’m going to zip tie it to the tube so it can’t pop out for now. Any thoughts?

 

[Scott Danforth]

I’m running Sierra Sae 30 synthetic oil per the manual.

Ditch the synthetic

Synthetic has proven to be problematic. It is no longer recommended by either Merc or VP

I recommend Rotella T4 15W-40

 

[GeorgeDes]

I’ve been running Mobil1 15w-50 synthetic without any issues except the oil pressure runs slightly high until the engine is warmed up. I have some Sierra 30w synthetic to try next oil change to see what effect that has. My VP manual calls for synthetic. I have heard it is not advisable to switch to a non-synthetic oil after having broken in and run an engine on synthetic for a long time. Something to do with the seals. Don’t know if this is an old automotive wive’s tale or not.

 

[Scott Danforth]

. Don’t know if this is an old automotive wive’s tale or not.

its a myth.

also, no such thing as too high an oil pressure. your oil pump has a pressure bypass set to about 70psi. so unless the oil pressure bypass spring and piston are stuck, your system max oil pressure is controlled by the fixed pressure oil pump. anything you read on the gauges is the difference between pump supply and leakage past the bearings

 

[alldodge]

I really wonder if this has anything to do with my problem. Several times I have noticed my oil dipstick has popped out quite a bit after running the boat on plane. With the dipstick hanging out, would that cause low oil pressure at idle? No idea what is causing this. I’m going to zip tie it to the tube so it can’t pop out for now. Any thoughts?

The dipstick has no effect on oil pressure

 

[GeorgeDes]

Yeah. I did see on the web that even the major oil companies have dispelled that myth about switching. Regarding the dipstick, when replacing it after checking the oil, I noticed that sometimes it does not always fully seat unless I jiggle it a bit and press it down fully.

 

[Mi_fiveo]

Got the boat on the water today. Ran 15 miles and came off plane. Same old problem, gauge shows low oil pressure and the alarm starts to go off. If I bump the throttle into forward and it idles up a little bit, the alarm then stops. I checked the dipstick after letting it settle for awhile and it shows over the full mark. I know I read another thread where too much oil was causing low oil pressure when it’s hot. Maybe that’s my problem. When it’s cold and I start it I get just below 40 psi consistently.

 

[Scott Danforth]

too much oil would cause the oil to froth as the crank beats around in the oil bath vs spinning happily above the oil bath

foamy or frothy oil will cause low oil pressure

it will also cause the bearings to soon be eaten as air is a poor substitute for a proper oil film on the bearing surface