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Dont know what year and have issues keeping it running. PLEASE HELP

D

Dgillis30

New member
I have a 15hp mariner outboard with a serial number 0d091569. I am not sure of the year and having issues keeping it running. It will fire right off then die. then it wont start. what the best recommended way to start them. Im wanting to get a Manuel for it.. I bout this boat off of someone thinking they sold it knowing it might have a issue. Thank you.
 
ok.. We will try that. Theres some days it runs great. Then others not so much and you fight it all day. It has a fast idle and slow. should it be started in a fast idle or no.
 
There are a number of common issues I see on these motors of this age.

Since this motor is new to you did you happen to get a history from the previous owner?

What I mean is, when was the water pump last done, gear oil, have the coils ever been replaced - anything else been done to it.

The motor is a little more than 20 years old now.

If you don't know then minimally I would replace the sparkplugs, the impeller and change the gear oil in the lower unit.

If that gets it running then either run a good dose of Seafoam with a tank of gas or better yet, stop into a Merc dealer and grab a can of Powertune (under 10 bucks) and just follow the directions on the can - either product will clean all the gunk/cooties/carbon out of the motor.

Some things that are known to go wrong and do go wrong with this particular model -

The main seals on the crank - most notably the upper seems to go more commonly than the lower. A toasted seal results in stalling when you try to idle.

The gasket on the intake cover at the transfer port. Again, similar symptoms - won't stay running unless you give it some gas.

Coils crack - if original they develop small spider cracks in the case. This can cause arcing back to the block robbing spark to the plugs - again, motor runs crappy.

In the past few years I have replaced coils, seals and gaskets on dozens of 1986-1994 portable Merc's 6/8/9.9/15. They are great motors but some parts don't last forever.

With a bit of maintenance these will last just about forever. They have a great carb and arguably the best ignition system ever developed for an outboard.
 
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