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Mercury Mariner 50 Hp auto-blend mixing problem

S

shaft

New member
I have Mercury Mariner 50hp 3 cylinder, serial #0C161068 with an auto-blend oil pump to mix gas.When I tried to start the motor, it doesn't start. I took the carbs cover off and Ifound out that there was only oil going to it. I traced from the pump at the side of the motor and the filter to the carbs and found only oil. The spark is fine. the motor will only start if the gas is added directly to the carbs throat but it shuts off when the gas is burnt out. I have checked all connections from fuel tank to auto-blend pump out to motor. I am not sure of the primer bulb, which location does it hook up to? Either the fuel tank side going to the oil pump or from oil pump to the motor inlet hook-up.
 
Take the auto-blend tank and throw it far enough away that it can't spontaneously reconnect.

You are extremely lucky. The auto-blend system was discontinued by Merc after a couple of seasons because it was very unreliable. What it mostly did was bust on the oil side of things so that it fed straight gas to the motor causing significant damage.

In your case you are lucky that the "gas side" of it shut down.

The auto-blend is not a variable system, it always mixes at 50:1 so you can scrap it and pre-mix your gas. You have pretty much no other option unless you want to try and find a second hand unit that's still working (I personally know of one unit on a 1990 motor that has worked great from day one and still going strong now - but also know first hand of at least two dozen rebuilds due to malfunctioning units).

There are no spare/replacement parts for the auto-blend system save the filter, so that's kinda where you stand....
 
thanks for the respond. how do you remove the auto-blend from the fuel system safely so I can run pre-mix gas.:confused:
 
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You have two choices.

1) you can run a new fuel line directly from the gas tank to the connector on the motor.

2) you can follow the gas line from the tank to the auto-blend and disconnect at that point - follow the gas line from the motor back to the auto-blend and disconnect at the auto-blend end - then use a (coupler) to splice the two together.

Then mix you gas at 50:1 with TCW-3 rated 2 stroke outboard oil (same stuff you put in the auto-blend tank)..
 
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