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Posted

Hi Raiders,

I had a go at servicing my 2001 90 HP Mercury 2 Stroke today.

I did the following:

  • Gear oil (see picture of old oil, please advise if there is anything I should be concerned about with the colour of the oil is this what would be considered milky?)
  • Spark plugs 
  • Impeller
  • Inline fuel filter 
  • Fuel water separator filter 
  • Carb clean (used the Yamalube aerosol) 

I noticed that when running the motor there is water coming out around the anodes, is this normal or am I missing a gasket (there wasn't one when I took the lower leg off) 

The carb cleaner seems to have caused some issues, the motor now misses when you rev it one of the carbs (the top one) back fires- I have run the motor for at least 30 minutes so I expect that the carb cleaner has been burnt off.

Thanks in advance for the advice.

I have a video of the motor running but cant upload it

 

Oil.jpg

Posted

Can't clean carbs by spraying them, looks like water in the gear oil, might be time for a quick pressure test, did you replace the washers under the drain/fill plugs, have you removed the prop to check for fishing line around the seal? not too sure where you mean the water is coming out, can you take a picture?

  • Thanks 1
Posted
1 hour ago, noelm said:

Can't clean carbs by spraying them, looks like water in the gear oil, might be time for a quick pressure test, did you replace the washers under the drain/fill plugs, have you removed the prop to check for fishing line around the seal? not too sure where you mean the water is coming out, can you take a picture?

Will try and post the video again

Posted

Another thing I noticed was a crack in the motor housing around the gear selector, it is in a very hard to notice place, I only noticed it when I was putting the lower leg back in. 

Judging by the corrosion around the crack I would guess it has been this way for a while.

If any raiders can please offer some insight on this.

Housing crack 2.jpg

Housing crack 3.jpg

Housing crack.jpg

Posted

Cant see a crack in the image but water is getting into your gear box somewhere.

 

@noelm Im interested to hear the pressure test proceedure.

I presume it would be connecting to the threaded oil inlet with an oil pump & just closing off the intake of the pump & pumping?

Spray some soapy water over the foot/crack??

Posted

Pictures are too close to make a lot of sense, gearcase pressure test is a common procedure and should be done, it does involve low pressure "pumped" into the gearcase, all shops would have an adapter, but you can make your own, use only low pressure to avoid seals popping out!

  • Thanks 1
Posted

I forgot, you don't have to block anything off to pressure test, you will hear air escaping easy enough, but proper adapters have a gauge and you want it to retain pressure, just like a leak down test on a cylinder.

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Posted

The oil looks not too bad if you had water intrusion it would be milky white colour. Carburettors need to be removed disassembled and cleaned all the internals. Water leaking around the anodes on the lower leg is normal. Pressure testing is done with air and a gauge if the pressure drops you have a leak. Then you need to fault find where the leak is usually a seal then you will need special tools and expertise to remove and replace 

  • Thanks 1
Posted

Most gear box seals can be done by anyone with reasonable mechanical skills, nothing scary about it, there's the drive shaft seal, (under the water pump) the shift rod seal and the prop shaft seal.

Posted

Here is a screen shot from the video of the water coming out near the anode 

I dropped the lower leg today, everything looks okay, I decided to use a bead of RTV gasket silicon all around the exhaust chamber. 

Seems to be a logical thing to do - are there any issues with doing this?

I also took the prop off today and no sign of fishing line behind the prop, going to take it in to have the gear casing looked at. 

I also noticed why the engine buzzer (the one that sounds as you turn the key and if something is wrong) is not working, it has been deliberately disconnected. I am guessing the oil level sensor went and the previous owner didnt want to replace it so chose to disconnect the entire system.

Overall I am glad I did the work on the motor, I have learnt a lot and feel like if something went wrong while out on the water I would have an idea of where to start looking.

Thanks for all the feedback so far, keep it coming. 

Capture.JPG

Posted (edited)

Picture is way too close to make out anything, there is no need to seal between the gearbox and the lower housing. Why do people disconnect the oil system? get the alarm working, if you get an overheat, it's going to be too late to do anything about it without the alarm.

Edited by noelm
  • Thanks 1
Posted

Is it a problem if I have made a seal around the exhaust chamber? 

I will get the alarm reconnected. I think the reason people disconnect them is because the flair switch is not sold separately it comes as a complete unit so it is pretty expensive. 

If I can afford to have the oil sensor reconnected I am going to ask if just the overheat sensor can be connected. 

I always check the oil level before going out and I always have oil in the boat with me just in case, but first prize is to get them all working. 

Posted
15 minutes ago, noelm said:

Is the oil injection still working? I thought you said it was disconnected?

Oil injection seems to be working the oil tank empties when the motor is run. 

I have added close 4 L of oil to the tank in about 20-30 hours of operation 

Posted

I found the attached diagram online, the two wires highlighted in yellow have been disconnected on my motor. There is also a tan/blue and black wire that I found have been disconnected. 

I will do the continuity test on the oil sensor as per the manual to confirm if it is faulty.

 

Warning system wiring diagram.JPG

Posted
On 7/19/2020 at 8:08 AM, Blade said:

Another thing I noticed was a crack in the motor housing around the gear selector, it is in a very hard to notice place, I only noticed it when I was putting the lower leg back in. 

Judging by the corrosion around the crack I would guess it has been this way for a while.

If any raiders can please offer some insight on this.

Housing crack 2.jpg

Housing crack 3.jpg

Housing crack.jpg

Took the boat in the mechanic said the crack is very unusual but won't cause any issues so happy about that. 

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