Oil pump/gear failure

[johnhibbs]

My oil pump/gear is working fine but I'm concerned it isn't not going to last for ever. When the plastic gear does break on the crankshaft the engine is going to self distruct. I can pre-mix the oil and gas but I would have to run a 50:1 mixture all the time. It only needs 100:1 during idle and it smokes enough as it is.

I found out that the Suzuki marine engines have an oil flow sensor on their engines. The part number is 16250-94710 and sells for around $20. I'm going to see if it's possible to use this sensor somehow on the output of the oil pump. It connects inline with the oil line. I will report back when I found out more. I don't know what type of signal the sensor generates but will find out.

 

[canadianwhiskey]

Cool, let us know.

 

[johnhibbs]

oil flow sensor

Just found out. Simple operation. A pressure diaphram is connected to a micro switch. When there is oil pressure the switch is open. When there is no oil pressure the switch is closed. Now to come up with a ciruit and audio alarm for it. Time to go to Radio Shack. The voltage to the alarm circuit needs to be powered ON only when the ignition is on. I don't know what the pressure level is to activate the sensor but since it's for anther brand V6 marine engine I would guess it's in the correct range. I will order one and do some testing to make sure it will work.

 

[canadianwhiskey]

I hope you get this figured out. It would be nice to be able to add something like this to my boat.

 

[johnhibbs]

oil pressure sensor

I just ordered a sensor from Ebay 16250-94710 Suzuki
I should have results in a week or two.

 

[johnhibbs]

Marine Engine Warning kit

I found a marine engine warning kit that does what I need. It is by Cole Hersee. The part number is M-40177-BP. It includes both an oil pressure sensor and a temperature sensor. You would have to cut the oil tube from the oil pump and install a T-adapter to measure the pressure. I was looking at the buzzers at Radio Shack and someone said that they don't last in a marine environment. This kit is designed for a marine environment. They sell them at West Marine but I found other places on the internet.

I already ordered the Suzuki oil sensor so I will put the buzzer it in something air tight.

 

[azirkhan]

Any progress on your project?

 

[johnhibbs]

oil flow sensor

I have the oil flow sensor but I've been lazy and haven't installed it yet. Maybe I will get around to it this weekend. I will do it before the weather gets warm. It's only in the 70's down here in San Diego. I think instead of using a buzzer I will connect it to the oil level float wiring at the top of the oil resevoir on top of the engine. Instead of buzzing, the red light will go off on the front display panel.

 

[TomB985]

BUMP!

Any progress?

 

[El Toro 33809]

Enquiring minds need to know.........

 

[johnhibbs]

I'm having my trailer brakes worked on today but I promise I will work on it this long weekend. I have the part. I will take photos when it's installed. Sorry for the delay.

 

[Double07]

Rather than just a buzzer or a light, you could also have it connected to a relay that can short out the lanyard connection switch.
That way, the motor stops the very moment reliable oil delivery stops.
With just the light or buzzer, what if you dont see the light or hear the buzzer when it goes off in the water with the glare of the sun and the loud sound of the motor at speed?
Just a thought...

-Chika

 

[johnhibbs]

oil pressure sensor

See attached photo of oil pressure sensor. I'm just hoping the inside diameter of the rubber hoses on the boat match the OD diameter on the pressure sensor. I will find out this weekend.

 

[DomsX20]

John,

Did you ever complete your project? I am rebuilding my Merc 240 right now because of a worm gear failure. I would like to prevent this from happening again if at all possible....

 

[buckeye_paul]

It's a very good idea! The part you bought from e bay was a flow sensor. Correct? The other kit had a pressure sensor. Not sure if a pressure sensor is what we need for this application. I hope you don't mind but I'm going to take this idea and run with it.

 

[DomsX20]

I am wondering how the Suzuki flow sensor works... Does it output a ground when it senses oil flow or does it output a ground when there is no oil flow? I guess it could be a 12 volt signal also... Either way, if the Merc has enough flow (it should) to activate the sensor, the modification could be very simple. Personally, I am considering a LED on the console to alert me....

 

[igneous]

Has anyone considered a stainless steel replacement for this plastic oil drive gear? Definitely a market for it with retrofits and rebuilds. Dont know what shape mines in, so prolly will go premix this summer

 

[buckeye_paul]

Changed my mind

After a lot of thought and careful consideration, I have decided not to go with the flow switch idea. A flow switch could work but it would need to sense flow between idle and wide open for the motor to run without alarm. Therefore, the motor could still be starved of oil and not open the switch. For example: The oil pump slows down because of the problematic worm gear and only pumps a mix of 100/1 (or less) at wide open throttle. The flow switch would still be closed and no alarm would happen.
I'm going to buy the block off kit and pre-mix. The cost of replacement for this motor is $4000 to $6000 and I can't afford that. It will be a bit smokier at the ramp, and be more work, but will be worth it for the peace of mind.

 

[Irish1800]

Does anyone know what serial #'s the plastic worm gear was in? I was told it was upgraded at some point, but I might've been told a white lie. Did Mercury ever upgrade it where it could be changed to a stainless steel or aluminum one? Is this gear internal or external?

 

[igneous]

I agree with buckeyepaul, the solution to the plastic gear has to be reliable (ie. work 100% of the time), and the electric pump could also fail. Where do you get a block off kit?

 

[Irish1800]

Has there been any upgrades based on certain years or aftermarket gears manufactured? I was told when I purchased mine that the oil pump gear wasn't a issue in my model year, but after reading this I guess I was misinformed by the Mercury Tech.

 

[Irish1800]

Has anyone considered a stainless steel replacement for this plastic oil drive gear? Definitely a market for it with retrofits and rebuilds. Dont know what shape mines in, so prolly will go premix this summer

I've pondered this as well and have actually considered purchasing one and having one machined out of stainless or aluminum by a machinist friend of mine. My question is do you have to completely disassembly the motor to get to the oil pump gear inside to replace it? If it's a easy fix/replacement then I believe I'm going to go forward with this idea and replace the pump at the same time. My boat doesn't have alot of hours on it, but being a nylon worm gear I'm guessing it wouldn't take alot of hours to wear it out and once failure happens we all know what happens. I can't believe Mercury didn't rememdy this as they still use the jetdrive motor setup although I'm sure they've went to 4 strokes like everyone else.

 

[DomsX20]

The engine must be totally disassembled to replace the worm gear. I THINK Mercury did not use a metal gear is due to the contraction and expansion characteristics of metal. This would cause a much greater potential to shear the worm gear if during expansion, the gears no longer aligned properly. It should be noted that Mercury did replace the original plastic worm gear with a stronger different material (still plastic).

 

[Irish1800]

The engine must be totally disassembled to replace the worm gear. I THINK Mercury did not use a metal gear is due to the contraction and expansion characteristics of metal. This would cause a much greater potential to shear the worm gear if during expansion, the gears no longer aligned properly. It should be noted that Mercury did replace the original plastic worm gear with a stronger different material (still plastic).

Do you know what model/serial # this was done?(replacement of stronger gear) I've got a engineer buddy that said he could easily machine one out of brass with no issues. I'm wondering if it's worth it or not. I could easily mix the fuel 50:1 or buy gasket sets and tear motor down and put new brass worm gear in.

 

[BMANN06]

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