Replacement/Rebuild of Mercury Optimax 115

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Fishhawk50

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I have a 2006 Nitro 189 sport with a Mercury Optimax 115. Last summer, the fuel lines disintegrated and clogged up the engine. My mechanic replaced the fuel line, fuel pumps, spark plugs and for good measure, the water pump. Later, I was still having problems with the engine quitting and running roughly. We thought cleaning the injectors would clear that up. When the mechanic checked the cylinders, #1 piston showed a 50% reduction in hp. He says I should get another engine before this piston throws a rod. Also, rebuilding the engine can cost as much or more that getting a used engine. Is this right? Can I find a comparable used engine that will fit my boat? Does anybody know what engine I should look for?
 

cceguy

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Did the mechanic say 50% reduction in hp, or compression? After getting at least 1 more opinion, I would opt for reworking just the one cylinder, if that seems to be the only problem. Might only need the one cylinder honed and new rings and rod. While the head is off, you can tell if there are other problems - and then decide if the cost is worth it. As far as getting a used motor, unless you can have it checked out by a good mechanic, you may be getting more problems. I would go for a remanufactured motor- one that has a good warranty. Getting a rebuilt powerhead is an option, but with the labor involved might be as much as a remanufactured motor. As far as getting another different motor, consider the cost of new controls if needed.
Another cost factor is how much of the work you can (or want to) do yourself. Caution - when I have tried to do part of the work, it cost more than if I had left it alone. Just my thoughts, but you asked.
 

AcousticNitro

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I have a 2010 115hp Optimax on my Nitro. Do I need to be worried about the fuel line disintegrating? Should I have it replaced before there's a problem? Or is this not a common problem?
 

Kirby Wilson

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Is the motor making noises? If not it could only be a fix of the single cylinder. I just blown a Mecury 150 hp last Friday. It was making noises (piston slap) and was able to limp it back to the dock. A rebuild is on the average of $4000 for a V6 outboard. New Mecury motor takes up to 52 weeks to get and newer used motors are difficult to find. Before buying a used motor have a compression check run on the cylinders and if posable have a Outboard Engine Computer Diagnostics done.
 

Kirby Wilson

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I have a 2010 115hp Optimax on my Nitro. Do I need to be worried about the fuel line disintegrating? Should I have it replaced before there's a problem? Or is this not a common problem?
Using ethanol Fuel you need to replace your regularly. I would ask a boat mechanic how often.
 

JohnB

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I have a 2006 Nitro 189 sport with a Mercury Optimax 115. Last summer, the fuel lines disintegrated and clogged up the engine. My mechanic replaced the fuel line, fuel pumps, spark plugs and for good measure, the water pump. Later, I was still having problems with the engine quitting and running roughly. We thought cleaning the injectors would clear that up. When the mechanic checked the cylinders, #1 piston showed a 50% reduction in hp. He says I should get another engine before this piston throws a rod. Also, rebuilding the engine can cost as much or more that getting a used engine. Is this right? Can I find a comparable used engine that will fit my boat? Does anybody know what engine I should look for?
I see that you're in Loudon, TN. If you don't mind me asking, where did you take it? There are only two places I trust in that area: Bunch's Marine in Roane Co. and Bluegrass Marine Repair (mobile mechanic in Knox area). I'm sure there are other good ones, but I know these folks personally and trust them implicitly. (Although I've also heard good things about Madisonville Marine.)

I agree with AcousticNitro - if it's low compression on a single cylinder, just have that one cylinder repaired. This is a very common practice with outboard motors.
 

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