Poor design, planned obsolesence

[DonV]

To those of you who have a 2stroke Mercury with an engine mounted oil tank and may be having oil alarm issues or even more important if it does happen to you, I might be able to help you diagnose the problem. Let me go over what happened to me last weekend.

My oil alarm went off (four beeps every two minutes), I tried to go out fishing because I knew the tank was full and the oil pumping from the big tank to the engine tank was working properly, however sooner or later the engine's computer will shut you down and put your engine in "safe mode"....it's a long way back to shore from 12 miles out at 1500 rpm.

When I got back to the dock I checked the oil and it was full and I was able to bypass the alarm to isolate the problem to the sending unit/float in the tank. Since the alarm was working the sending unit (switch assembly p/n 856156A2) was eliminated as the problem, the problem is the float system in the tank that uses a magnetic washer to activate the sensor.

First picture is what your float looks like when the tank is low or out of oil ( I just had to cut the damn tank apart) the float and magnetic washer are at the bottom of the shaft.


The second picture is when the float is at the top and the sensor sees the tank is full


And the third is what the problem is, the black magnetic washer has separated from the float and stays at the bottom of the shaft sending a false "out of oil" signal. The washer is actually glued to the BOTTOM of the float.....what??? How dumb is that, why not on top of the float????


Anyway maybe this will help someone.....oh yeah, a new tank is a smooth $75.

[flyingfrizzle]

Originally Posted by DonV

Anyway maybe this will help someone.....oh yeah, a new tank is a smooth $75.

This is a "known issue" with the mercury oil injection, even worse the plastic gear on the crank shaft that can strip out and cause the oil pump not to run. The newer models have injection oil pumps that are electric and driven by the computer but the older ones are crap. First thing I do with a mercury is gut the oil injection and install a cap off kit in the block. Pre mix is the way to go on the plastic gear pre 2000's models. After that the other style is more reliable.

If you need a tank with a good float PM me I got 5 or 6 of them and can send you one if you haven't already gotten one.

[DonV]

Thanks Frizz, already bought one so I could fish Saturday. I'll keep you in mid for sure!!!!!

[doodlebug]

Don , both of my opti's did the same, I just made jumpers for the wires.
Two tanks twice the problems 4 years and going strong.

[DonV]

Howdy Duane, I thought about just leaving the wires connected together after I did my testing to isolate the problem, which means you have no alarm. If the tank was like the 90 Opti for example where you can just remove a simple cap and look at your oil level, versus removing the cowling on the V6 engines, I would have left it that way. However "Mr. Murphy" is always close by me and if the little tank under the cowling empties at 4000 rpm you have just bought a new engine....not in my retirement budget!

Take care!

[DonV]

Yeah think about it. It's the same sending unit in all their tanks, from what I've seen, and it seems to be a very common problem! I've got a few simple solutions, 1. attach the magnetic washer with tiny screws to the float 2. split the float and place half above the magnetic washer and half below 3. put the washer on top of the float 4. don't use a metal clip under the "stop washer" at the bottom of the unit, that metal clip holds the magnetic washer from moving up on it's own 5. make the plastic unit removable and not seal it in the poly tank (the Chinese can make this thing for about $.45 and it can be sold for a profit at $5) 6. and a real simple one, make the float magnetic or with the magnetic ring around the circumference embedded in the float.

I could come up with a quite a few more however they would work and NOT break, would be too simple and Mercury would not be able to get me for $75 for a new tank. I'm done venting.