kkcaudy

Sometimes when i start my 15 horse 4 stroke engine the oil lite will stay on and the engine runs ruff. If i shut it down ,and tilt the motor up ,then put it back down into the water and restart it everything is good. Does anyone have any idea's what the problem my be?

FourchonLa. Loc: Fourchon Louisiana, South Louisiana

Sounds like you have a float or some type of liquid level sensor sticking.

Gripnriprod Loc: Concepcion Costa Rica

Be sure you are using the right weight oil.

kkcaudy

That is what i was thinking , guess I'll have to trouble shoot the low oil sensor . Thanks .

ricky risteen

There is only one oil sender. You can check the sender with a ohmn meter for continuity. or you can take a oil pressure gauge & check it that way. To do that pull the sender & install a fiiting into the block & install your gauge. check pressure should be a least 20- 30 lbs. if real low thats the problem. The Ricky Sitka

kkcaudy

Thanks .I'll do that

Papa Bear JD Loc: Interlochen, Michigan

Don't know much about 4 stroke motors. But is there a way to check oil level like a dipstick on a car engine? if so, that's where I'd start my trouble shooting.

Jeremy Loc: America

Oil viscosity. Use thicker oil. Maybe 30W instead of 5/30 or 10/30. But first I would replace the oil pressure sending unit. If light shuts off after you flip engine up then restart it it points to a bad sending unit. It could also need to have air bled out of oil galley ways and the sensor. Air will compress and not move the diaphragm switch as far. Can bleed air out by starting the engine with sending unit out. Shut off immediately once oil squirts out. Immediately put sender back in. The problem could also be Teflon tape in the hole that is blocking oil. Tapered threads do NOT need Teflon tape and most oil senders are tapered.

If when light is off and engine is idling pull fuel line off and let it run out of fuel and it should stall and light should not turn on for a second or so. That is how long it will take for oil pressure to drop after engine stops ( pump stops ). If it is not rattling ( knocking ) making excessive noise it’s probably the sender. The sender is simply a rubber diaphragm that pushes against a spring loaded contact points. So when pressure goes away it makes contact which turns a light on.

kkcaudy

Thanks for the troubleshooting information, sound s good.
KKC

Whitey Loc: Southeast ohio

Check oil level first before anything else

Jeremy Loc: America

Whitey Loc: Southeast ohio

Yea an if oil is to low then that will shut it down. Right

Jeremy Loc: America

Shut it down or turn a light on. I think some boat motors have a switch on the ignition instead or in addition to a light.

Jeremy Loc: America

I just googled 2018 Mercury 15HP 4 cycle oil pressure sensor. It could be weak or low oil for sure. Hopefully the owner checks oil level anyway. I have seen people use teflon tape on tapered threads so many times and i see a little end of it block the hole so oil cant pressurize the switch. Symptoms point to a bad switch if its full or plugged. if has sludge or water in oil can cause problems for sure.

Jeremy Loc: America

This Laura is going to be a mess in next hours for days. 125MPH right now there. People should of left. I would of left the whole area PERMANENTLY to be honest. I hear its cheap to live there ......and that comes at a cost.