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1 clean spark plug

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sacalait1971

New member
Have a mercury 225 opti with 49 hours on it. Life challenges left boat sitting for 8 years. Starting to get it ready to run again. Pulled plugs and one plug looked like it was out of the box. What could have caused this or what should I look at before I try to start motor?

The engine ran great before storage
 
A clean plug results from , a bad sparkplug , no fuel , too much fuel, no spark or zero compression.-----I would start with a compression test and a spark check.----Good spark is considered to be able to jump a gap of 3/8" ( 1 cm ) or more.
 
Good advice and hey.......BE SURE TO PUT IN A NEW WATER PUMP IMPELLER!!!!
Drain all old fuel and flush lines with fresh clear non oxy fuel. You certainly don't want to use ethanol with your operating schedule.....it has VERY short life.
 
Water intrusion into a cylinder can actually steam clean a spark plug. Perhaps you have had a slight leak for some time but not enough that you noticed a change in performance.
 
ddc11 said:
Water intrusion into a cylinder can actually steam clean a spark plug. Perhaps you have had a slight leak for some time but not enough that you noticed a change in performance.
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That's my thought. With only 45 hours when you put it away, one wouldn't think that salt water passage pitting/corrosion would have been the cause. I had a water intrusion engine once before and it is amazing what water can do in a combustion chamber....as long as combustion is present....steam cleaning personified.
 
Texasmark said:
That's my thought. With only 45 hours when you put it away, one wouldn't think that salt water passage pitting/corrosion would have been the cause. I had a water intrusion engine once before and it is amazing what water can do in a combustion chamber....as long as combustion is present....steam cleaning personified.
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A 2 stroke with water in the cylinder will trash the crankshaft in short time.... Doubtful that he has a water issue...

There is a chance the cylinder liner is out of position but it is not likely.....
 
So just to clarify, the engine likely had the issue before storage? But hasn't ran yet? Was it winterized?
I would swap the ignition coil from another cylinder and see if you're now getting spark to that clean plug. I've had this issue on Optimax.
 
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