Oil Pressure Alarm

[Joey9851]

The shop is working on getting my new to me motor installed (2019 Mercruiser 4.3) and is having an oil pressure alarm issue. The original motor was a TKS and it’s being replaced with an engine without TKS (bought the engine with 5 verified hours for $1600 instead of $11,000 from mainland). The tech is going to diagnose next week but curious as to what direction you all can point me in so I’m not getting screwed on labor costs (already way over my budget). I have an oil sending unit in a box at my house, and the tech had to splice the engine to hull connector to get the motor installed correctly. Anything else to look for? I had them change the oil and all filters as part of the job too

 

[Fun Times]

Are both engines complete MerCruiser engines including all sensors and accessories/hardware/wiring,etc. or are certain parts being switched over to make the other work, etc.?

Is the other (new) engine carburetor or MPI?

Do you happen to have the MerCruiser serial numbers to either the new or both if parts are being swapped around.

Did the oil alarm come on before or after the new oil filter was installed?

tech had to splice the engine to hull connector to get the motor installed correctly

Any other details to share on this procedure?

 

[04fxdwgi25]

I would install a cheapie ol mechanical oil pressure gauge in a "T" where the oil alarm sender sits, pull the spark plugs and spin it over with the starter.

That'll tell you if you have oil pressure / wiring problem or not and if it's just a bad sender or a bigger problem.

 

[Scott Danforth]

First, use the mechanical gauge to verify oil pressure

Second, the alarm is tied to oil pressure, gear lube reservoir, temp switch and a few other things. Trained marine mechanics will know this and be able to troubleshoot

Third....why not swap the motor yourself?

 

[Grub54891]

All the comments before are good. I've had customers who had alarms, a lot of times it's the drive reservoir float that is stuck from gunk. My usual service is removing the reservoir and flushing it out.

 

[Joey9851]

Are both engines complete MerCruiser engines including all sensors and accessories/hardware/wiring,etc. or are certain parts being switched over to make the other work, etc.?

Is the other (new) engine carburetor or MPI?

Do you happen to have the MerCruiser serial numbers to either the new or both if parts are being swapped around.

Did the oil alarm come on before or after the new oil filter was installed?


Any other details to share on this procedure?

Both were complete Mercruiser engines, only thing missing was the connector from engine to hull. Both carbureted. Original serial is 1A066831 and new is 1G415169. Nothing from the original engine was saved

 

[Joey9851]

I would install a cheapie ol mechanical oil pressure gauge in a "T" where the oil alarm sender sits, pull the spark plugs and spin it over with the starter.

That'll tell you if you have oil pressure / wiring problem or not and if it's just a bad sender or a bigger problem.

They tested the oil pressure with it running and it’s within spec, it’s just the alarm. Since my insurance company requires no alarm mechanisms activated, they have to get the alarm to stop.

 

[Joey9851]

First, use the mechanical gauge to verify oil pressure

Second, the alarm is tied to oil pressure, gear lube reservoir, temp switch and a few other things. Trained marine mechanics will know this and be able to troubleshoot

Third....why not swap the motor yourself?

First: they said the oil pressure was within spec on the boat gauge and manual gauge and engine runs great.
Second: they might not have filled up the fluids other than the oil when they tested it as they were confirming the harness work so I’ll bring that up to them. They don’t have techs that specialize in marine specific engines. They have an engine guy, an alignment guy, a drive guy and an electrical guy.

Third: My insurance company required that it be done by a shop. I filed a claim because the shop believed that the exhaust manifold failure that resulted in water intrusion would be covered. I don’t have the space or tools to do it myself. Mainly the ability to lift the motor and do the alignment.

Hopefully they get it finished up tomorrow so I can enjoy it before I have to sell as I’m getting ready to move back to the mainland from Hawaii

 

[Joey9851]

All the comments before are good. I've had customers who had alarms, a lot of times it's the drive reservoir float that is stuck from gunk. My usual service is removing the reservoir and flushing it out.

Is this the reservoir mounted on the front of the engine, in front of the exhaust manifold?

 

[Scott06]

Is this the reservoir mounted on the front of the engine, in front of the exhaust manifold?

yes clear plastic bottle about a pint in size

 

[Fun Times]

Both were complete Mercruiser engines, only thing missing was the connector from engine to hull. Both carbureted. Original serial is 1A066831 and new is 1G415169. Nothing from the original engine was saved

Thanks for sharing your serial numbers as it helps narrow down possibilities between the 2 engine models < and settle some of my Spidey senses as they were tingling on this one because your 1A066831 comes up as being a MERCRUISER 5.0L MPI ALPHA 1.7R DRAIN 5.0L ALPHA MPI

While your 1G415169 comes us an MISCELLANEOUS REMAN 4.3 ALPHA 4V REMAN - which your correct this engine will be a 4BBL carbureted version…

Here’s you part catalog for this model if ever needed, https://www.mercruiserparts.com/4-3l-gen--4bbl-reman-1g400000-thru-1g416776

https://www.mercruiserparts.com/Bam/GetSubNodesBySerial/1A066831

That mentioned, sort of interesting that the engine size went down though the HP may stay close to each other but might effect either gear ratio and/or propeller sizing overall… have those concerns been addressed?