Low oil alarm on 1998 mariner 150 mag III

[eddiec]

Hello all,

New to forum and first post after having spent 2 days reading searching for someone with my exact problem. Apologies for duplicate question if one already exists.

Going across lake on plane and low oil alarm sounds, loud constant beep beep beep. Immediately shut engine down and checked remote and engine tanks, both full. Turned key on, got the usual 3 beeps, cranked engine and constant beep beep beep resumed. Running on hose engine producing usual smoke upon cranking and running. In lake engine cranks and runs normal. The only thing I have changed is the cranking battery the eve before since the old one died.

Over last 6 months, I have noticed while at slow idle the engine acts as if its running out of gas and dies. After pumping bulb it cranks and runs fine. When engine first cranks cold idles rough and may die several times, after warming up, runs fine. Other thing I have noticed is the tach acting squirrely at times but soon settles down.

Any help greatly appreciated.

 

[achris]

Re: Low oil alarm on 1998 mariner 150 mag III

There are excellent oil problem diagnositics in the manual. The question I'll ask is 'When were the fuel pump diaphrams last replaced?"

Chris......

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

There are excellent oil problem diagnositics in the manual. The question I'll ask is 'When were the fuel pump diaphrams last replaced?"

Chris......

Thanks for reply, I bought the boat/motor/trailer used with app 50 hrs on it. I did not get a manual upon purchase and haven't purchased a repair manual, "yet". Looks like I'm about to need one though. As for the fuel pump and diaphragm replacement, the answer is never.
Until now have had no problems.

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

I'm not too concerned with the idling problem. My biggest worry is te alarm.

 

[CharlieB]

Re: Low oil alarm on 1998 mariner 150 mag III

Do NOT continue to run the motor until you add oil to your fuel at a 50 : 1 mix

If these IS a problem with the oil system the pre-mixed fuel will prevent damage.

Besides the low oil level sensors the alarm module compares the pulses of the oil pump rotation sensor to the ignition pulses, usually off #4 coil. When the module sees a difference in these signal it raises an alarm.

You will need to check the oil pump/drive, and rotation senser as well as a spark test to see what the fault is.

 

[pinellas50]

Re: Low oil alarm on 1998 mariner 150 mag III

I had this on my 96 115. In my situtation the magnet on the oil level sensor in the tank fell off and caused the sensor to trip and keep the alarm sounding. My fix was to simply replace the oil tank which has the sensor in it.

I'm not down playing what is said above. You absolutely must verify your motor is getting oil. And I agree with everything written above.

Does the alarm sound when the key is turned to run but the motor is not running? I believe my alarm would go off even when the motor was not running.........but it has been awhile since I messed with this so I'm not certain of that at this point.

A question for those much more knowledgable than me. Could OP simply unplug the wires going to the low oil level sensor to diagnose? Would disabling the oil level sensor also disable the rest of the oil alarm system?

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

I had this on my 96 115. In my situtation the magnet on the oil level sensor in the tank fell off and caused the sensor to trip and keep the alarm sounding. My fix was to simply replace the oil tank which has the sensor in it.

I'm not down playing what is said above. You absolutely must verify your motor is getting oil. And I agree with everything written above.

Does the alarm sound when the key is turned to run but the motor is not running? I believe my alarm would go off even when the motor was not running.........but it has been awhile since I messed with this so I'm not certain of that at this point.

A question for those much more knowledgable than me. Could OP simply unplug the wires going to the low oil level sensor to diagnose? Would disabling the oil level sensor also disable the rest of the oil alarm system?

alarm only sounds when motor is running.

 

[sxmerc]

Re: Low oil alarm on 1998 mariner 150 mag III

Get a manual, follow the troubleshooting flow chart. Very easy diagnostics to follow. pinellas50... tank on your 115 is different from this one. On the small block V-6's, the oil sender is built into the cap, and is replaceable seperate from the tank should this be the culprit.

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

Get a manual, follow the troubleshooting flow chart. Very easy diagnostics to follow. pinellas50... tank on your 115 is different from this one. On the small block V-6's, the oil sender is built into the cap, and is replaceable seperate from the tank should this be the culprit.

Thanks to everyone for all the replies. Got a manual on the way.

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

Thanks to everyone for all the replies. Got a manual on the way.[/QUOTE

recieved manual and followed diagnostics. Also noticed tach is pegged out when engine idling. according to my reasoning,I have decided it is the warning module that is defective.
Any suggestions before I replace it?

 

[sxmerc]

Re: Low oil alarm on 1998 mariner 150 mag III

What did the flow chart point you towards? Tach may be a completely seperate issue.

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

manual indicated it may be a motion sensor only used on 1998-99 mariners. spoke with a local mechanic who immediately said it was the warning module. there is a green wire from warning module to tach which makes me think the two symptoms r related.

 

[j_martin]

Re: Low oil alarm on 1998 mariner 150 mag III

Not sure about that year magIII, but the green wire always used to go to the #2 coil driver terminal. If it indeed does go to the tach as said, then the common item would be a bad voltage regulator that drives both. That would set off the alarm.

What is the serial number of your engine?

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

Thanks for the reply. I was reading from the Clymer manual and misread it. The green wire from warning module is the tach signal from switchbox, pardon my stupidity.

I know I need to change the plugs since I havent done so in 3 years, and the motor does have a low rpm miss that clears up on high rpm. The tach also pegs out with engine at idle which makes me think a misfiring cylinder may have set off alarm or damaged warning module. Not sure thats correct though.
I hate to admit that I used to be a shop foreman at a trucking company, and thought I was mechanically adept. Boat motors have me beat.

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

OK, Have found the problem for oil alarm. Removed oil pump and driven shaft and found telltale gray plastic shavings on gear. I've been told it's not worth splitting engine to replace plastic oil pump drive gear on crank. Decided to remove oil injection and go premix. My question is, what do i need to remove to do away with injection and what do i unhook to disable oil alarm. Any advice much appreciated.

 

[j_martin]

Re: Low oil alarm on 1998 mariner 150 mag III

Re: oil injection removal Merc V6 only

You need part number 43453 if it is available. That retains the pump driveshaft bushing and plugs the hole where the pump mounts. Then remove the oil components and the warning module. You'll also need to remove the fitting that the oil tank pressure hose attaches to and plug the hole in the block.

Order three stickers (37-818029 1), one to mount near the fuel fitting on the motor, one for the dash, and one near the fuel fill fitting on the boat. They'll alert the operator that the gas needs to have oil added. One frequent problem we see here regards the infamous "brother-in-law" that forgets to add oil to the gas and roaches the motor.

You should probably replace the fuel lines where the fitting for the oil T's into the fuel line with a single piece of fuel line.

hope it helps
John

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

Re: oil injection removal Merc V6 only

You need part number 43453 if it is available. That retains the pump driveshaft bushing and plugs the hole where the pump mounts. Then remove the oil components and the warning module. You'll also need to remove the fitting that the oil tank pressure hose attaches to and plug the hole in the block.

Order three stickers (37-818029 1), one to mount near the fuel fitting on the motor, one for the dash, and one near the fuel fill fitting on the boat. They'll alert the operator that the gas needs to have oil added. One frequent problem we see here regards the infamous "brother-in-law" that forgets to add oil to the gas and roaches the motor.

You should probably replace the fuel lines where the fitting for the oil T's into the fuel line with a single piece of fuel line.

hope it helps
John

Thanks for the reply John. I have removed oil pump,plastic coupler, and shaft from crank that drives oil pump. Dont know of any bushings, but since i have already removed shaft did bushings drop somewhere inside engine? Hope not!!

Also, where did remainder of plastic shavings end up? And what to do with linkage that was hooked to oil pump? Last but not least,what if that part isnt available, can i put oil pump back on without drive shaft and plug holes?

 

[j_martin]

Re: Low oil alarm on 1998 mariner 150 mag III

Thanks for the reply John. I have removed oil pump,plastic coupler, and shaft from crank that drives oil pump. Dont know of any bushings, but since i have already removed shaft did bushings drop somewhere inside engine? Hope not!!

Also, where did remainder of plastic shavings end up? And what to do with linkage that was hooked to oil pump? Last but not least,what if that part isnt available, can i put oil pump back on without drive shaft and plug holes?

Bushing probably didn't drop in.
Plastic got digested. Probably no harm done.
If you can't get the plug, put the pump on without the gear.

hope it helps
John

 

[eddiec]

Re: Low oil alarm on 1998 mariner 150 mag III

Bushing probably didn't drop in.
Plastic got digested. Probably no harm done.
If you can't get the plug, put the pump on without the gear.

hope it helps
John

Thanks John--there is a bushing on the oil pump side of the plastic coupler that came off with the pump, are u referring to an inner bushing between coupler and crank? I'm also assuming i should remove shaft/gear from oil pump before putting it back on.

As for removing the warning module, that is the one on port side of the engine, correct?
Apologize for being such a pain, but manual doesnt cover removing oil injection system and going to premix, and boat motors scare the crap outta me.

 

[j_martin]

Re: Low oil alarm on 1998 mariner 150 mag III

Thanks John--there is a bushing on the oil pump side of the plastic coupler that came off with the pump, are u referring to an inner bushing between coupler and crank? I'm also assuming i should remove shaft/gear from oil pump before putting it back on.

As for removing the warning module, that is the one on port side of the engine, correct?
Apologize for being such a pain, but manual doesnt cover removing oil injection system and going to premix, and boat motors scare the crap outta me.

I think there's a bushing that the end of the oil pump shaft goes into. That'd be the one to worry about. The other thing the plug does is fill some crankcase volume as the pump would have. Crankcase volume is important in 2 cycle.

I believe that module is on the port side. Follow the wires from the sensor and the oil tank. Just completely remove the module.

2 cycle is half as complicated as 4 cycle. Don't let it bother you.