MerCruiser 120 84 oil pressure help....

[daydreamer1252]

I posted this a few weeks ago and response I got little hasn't worked out. Hope this goes better....this time I have PICS....

Putting a basket case back together......took it apart 2 1/2 years ago and some of the memory is fuzzy. I believe that the first picture shows where the oil pressure sender is supposed to be located....

Have filled the oil sump and a new filter...primed the oil pump with about 3oz of oil (down the distributor hole) and have run the pump with the device in the second picture....connected to a 1/2 inch VSR drill......clockwise rotation viewed from above.....drill turned about 5 to 10 seconds and then bogged this would seem to make me think that I have gotten the pump to pick up and actually pump oil unfortunately the valve cover is in place and cannot see any actual oil movement....

Am not getting anything out of the hole that I believe to be where the oil pressure sender should be located.....this hole has pipe threads that match those on the oil pressure sender...

This hole was plugged by a mud dauber, I cleaned out the hole and ran a tap over the threads to clean them out.....

I am concerned that the hole in the oil pressure source that feeds this larger hole is still plugged.....

Try as I might I cannot get into a position to see INTO this threaded hole....I need to know where in the big threaded hole the hole to the oil source is so that I might clean it out.....

Is the hole straight in and in the middle or at the top right (forward) or does it come in from the rear and right in the center....really need some help here....as far as I have come I really don't want to have to pull the engine for this....

all help and advice is appreciated....

 

[Bondo]

Re: MerCruiser 120 84 oil pressure help....

Ayuh,.... The motor can't build oil pressure without the distributer Body in-place...
Only the mains are seeing oil with your screwdriver thingy...

 

[coheej]

Re: MerCruiser 120 84 oil pressure help....

The hole you show in the first picture appears to be an ordinary motor mount hole for some other possible application. The oil pressure sender hole should be higher on the block and not down along the pan rail. Could you post a picture of the entire side of the motor.

 

[fishrdan]

Re: MerCruiser 120 84 oil pressure help....

I agree with both posts. The oil pressure sender is above the starter, the hole you posted isn't it.

Courtesy of google images...

sender location

 

[86 century]

Re: MerCruiser 120 84 oil pressure help....

If that pic doesn't help I think I have three 140s one early and two mid 80's would be glad to take some pics for you.

 

[daydreamer1252]

Re: MerCruiser 120 84 oil pressure help....

Bondo - Thanks for that, I had heard that was a factor in SBC configurations but didn't know
it held true for the 4 cyls also.

coheej and fishrdan - That completes the answer....found that hole and when I checked and found 1/8 npt threads I was reasonably sure it was for the oil sender:redface: ...after your comments and fisherdan's pic I had another look and there is a hole above the starter that is plugged with cardboard or maybe a felt like material and subsequently painted over it's really dark under there in the direct sunlight.....the engine had been rebuilt by one of the oldest rebuilders in Dallas and apparently they felt the hole was important enough to secure it.....now all I have to do is to figure out how to get the sender in there.....looks mighty tight........

86 century - photos are always appreciated as I am not sure how many other misplacements :redface: may be around here.......as I said the memory is fuzzy from a couple years ago......and unfortunately the photos in the OE manual are not that great in seeing detail........

Thanks all, your help is invaluable...