Logo

Mercury '95 40HP 4 stroke oil location

csymmondsva

New member
In short, I can't figure out how to check or change the oil and filter - can't find anything on the motor or online.
I'm amazed at the collective wealth of information and those will to help on this forum, so thought I'd try.

I have a 1995 Mercury 40HP, 4 cylinder, 4 stroke model "1040412RT 1995 40 HP ELPTO" that I inherited. I know nothing about the motor and not having luck finding reference materials.
Mercury's own site presents manuals for the wrong model (for two stroke) when I enter the serial number.
I've watched several videos, all are different models and the oil filter, dipstick and fill cap are all plainly visible - not on mine.
Since the motor has been in storage for years, I wanted to do a thorough sanity check before trying to start it.

I am hoping someone has this model or is familiar and can provide some insight, or know where I can find the correct reference manual(s).
Photos of both sides attached.
Thanks in advance.
 

Attachments

  • 20250529_124136.jpg
    20250529_124136.jpg
    332.6 KB · Views: 56
  • 20250529_124200.jpg
    20250529_124200.jpg
    324.1 KB · Views: 40
Easy.-----Your motor is not a 4 stroke !!!-----Need to mix gas / oil at 50:1 ratio.----Hopefully you have not run it on straight gas.
 
Easy.-----Your motor is not a 4 stroke !!!-----Need to mix gas / oil at 50:1 ratio.----Hopefully you have not run it on straight gas.
That makes sense, thank you!
That also explains why I had difficulty finding reference material.
The reference to 4 stroke came from a online source, but now I see it is two stroke.
I've not tried to run it and won't until I'm confident and know more.
 
Read an owners manual.----Read it twice before you turn the key!----And ----online , can be a good source for BAD information.
 
I will, at least twice. The manual will be easier to find now without the bad information found earlier.
I also have an experienced mechanic that's going to do a sanity check before trying to run it.
 
The oil tank has been removed, did you do it? As stated, don't start this engine until you fully understand what you have there. They were very nice running engines, the basic design started in 1955 and ran all they way up to 1997 production in different variants..
 
The photos show the motor as received.
I was next going to ask about oil injection since I believe the ELPTO indicates oil injected.
No clue what previous owners may have done. I also noticed some disconnected wires. Now that I've got the model details, got the manual I hope I can determine if it's worthwhile trying to salvage
 
Compression test, spark and gearlube check. These motors are about 130-138 psi compression. Disconnected wires may be from the low oil sensor in the bottom of the oil tank that's not there anymore.
 
Thanks. I still have a way to go before I can even turn it over to check compression. The wiring is another challenge, apparently a prior owner didn't like wiring, and much detail I find online for the throttle control doesn't match what I'm looking at for what is supposed to be the kill switch.
 
Well luckily for you, I have a the exact same 40 hp engine I bought brand new in 1995 including the factory service manual. The only item that's ever been touched on it is a CDI new stator. So if you need reference photographs, I can email them to you. Unfortunately, I do not have the standard remote control box for it.
 
Thanks.
I am beginning to think the remote isn't standard on this one either. I can't move the on/off switch to the off position - there's no clearance between the toggle switch and the cover over the switch.
At some point I'll likely remove the remote to see if I can figure out why. At present there's no way to get the kill lanyard over the toggle as there's no clearance.
 
Well luckily for you, I have a the exact same 40 hp engine I bought brand new in 1995 including the factory service manual. The only item that's ever been touched on it is a CDI new stator. So if you need reference photographs, I can email them to you. Unfortunately, I do not have the standard remote control box for it.
I got the on/off switch figured out. It's difficult to move to the off position without the lanyard key installed but a paper clip worked...now seems easy.
Next is to confirm the wiring and I've had no luck finding a service manual either online or to buy.
Everything I've found is for 1998 and later. Is there a part number somewhere on your service manual for the document itself? That might help finding the right manual.
Or by chance, do you know of a source for either electronic or printed?
Thanks again.
 
Back
Top