Optimax 115 puttering out violently

Gnewell

Recruit
Joined
Aug 1, 2018
Messages
2
New to the forums! Having big problems with my twin 2004 mercury Optimax 115. Just had the spark plugs replaced by a mercury dealer in town, as soon as I put it in the water, I go to run the engines and they turn on quite rough. but the motor starts to violently putter out and then immediately dies.

Sometimes the port motor will last a few seconds before dying out but the starboard one immediately goes out.


I checked oil levels, and fuel levels all good. i don’t really have any idea to what’s going on. I had friend run some diagnostics and he told me that banks 4,5, and 6 weren’t firing. I called up the dealer and they told me it had nothing to do with the spark plugs they replaced.

Anyone have any ideas of what the issue is?
 
Last edited:

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,571
So both engines were running properly, and then the dealer changed the spark plugs. Now both are running poorly? Seems like checking the type of spark plugs and the condition they are in would be my next move.

Optimax usually call for iridium spark plugs ($17 each). Is that what he put in?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,571
I don't think you need to index the spark plugs, but you should check.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,263
What do you mean by ----banks 4,5 and 6------Are these 3 cylinder motors ??
 

ajgraz

Lieutenant Commander
Joined
Mar 1, 2010
Messages
1,858
Sure sounds like it's got something to do with something the dealer did...or didn't do...or did accidentally...

See any disconnected harness connectors under the cowling? Are the spark plug connectors on correctly (and on the correct plugs)?
 
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