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Author Topic:   1999 Mercury OptiMax Won't Start

grossjas posted 05-15-2010 02:23 PM ET (US)
I bought a used boat with a [1999] Mercury Optimax. [The Mercury OptiMax] started right up about a month ago. Now that it is boating season in northern Michigan, I went to start [the Mercury OptiMax] today, and it will not even fire. The [Mercury OptiMax] is new to me. I know nothing about it. Am I missing something? Help.
jimh posted 05-15-2010 03:42 PM ET (US)
It is unlikely that there has been much wear and tear on the engine from a month of sitting idle. On this assumption we turn to other causes for the failure to start, external to the engine itself. Most notable is the battery.
The short version: If the battery is more than three years old, discard the current battery and replace it with a new battery with a MCA rating of 1,000-amperes or more. If the battery is less than two years old, recharge it.
The long version:
A Mercury OptiMax needs a very strong battery to start. Typically the battery must voltage must not sag during engine cranking. The OptiMax cannot be started without an external supply of electrical power to operate its electrical system. The electrical system of a Mercury OptiMax is a net consumer of electrical power until the engine speed reaches a fast idle. The Mercury OptiMax needs electrical power to run:
--the engine control unit (ECU) computer electronics;
--the electrical fuel injectors
--the electrical air injectors
Until the engine starts, all electrical power must be supplied by the storage battery used to crank it over. During engine cranking, if the battery voltage sags, it is very likely the ECU computer will not operate properly. The engine may very likely be impossible to start without a strong battery. The Mercury OptiMax is very well known for its demanding starting battery specifications. The minimum MCA rating for the battery is 1,000-amperes.
To eliminate the battery as a possible cause of the no-start, I recommend you follow this procedure:
--check the battery electrolyte level; refill to proper level if low
--fully charge the battery with a proper charger; allow the battery to reach 100-percent charge and float there for a day to insure complete charging of the battery and restoration of cell chemistry; after letting the battery equilize its charge for several hours, measure the terminal voltage with a voltmeter with 5-percent accuracy. You should see at least 12.8-volts.
--check all electrical connections between the battery and the Mercury OptiMax; by this I mean you should remove all connections, clean all terminals, remove any corrosion, restore all connections, tighten all retaining nuts or fasteners.
Then, try restarting the Mercury OptiMax. Since it ran a month ago, it should run now. If this electrical service does not restore starting, investigate the fuel system. We can offer more advice on that once you check the electrical system.
jimh posted 05-15-2010 06:10 PM ET (US)
Using a search of the archives of CONTINUOUSWAVE with the search arguments "OptiMax" "No" and "Start", I found
http://continuouswave.com/ubb/Forum3/HTML/015027.html --an article describing how replacement of the starting battery returned the engine to normal starting;
http://continuouswave.com/ubb/Forum3/HTML/013626.html --an article describing starting problems and a recommendation to check the battery.
RevengeFamily posted 05-16-2010 06:30 AM ET (US)
Jim is 100% correct. I have twin 1999 Mercury 225 Optimax on my 1999 285 Conquest. With other engines you may be able to "squeek by" with a dieing battery, but not with the Optimax.
I experienced something similar once before. I left my slip and motored 30 yards to the fuel dock. Shut the engines down and fueled up. (fueling took 20 minutes) To restart the engines I had to squeeze the primer bulbs again. Thought it was a bit strange considering I did not tilt the engines and they had been warmed up at the slip. Not sure what happened, but Optimax are definately a strange breed.
jimh posted 05-16-2010 10:49 AM ET (US)
Here is another good discussion from the archives on solving the problem of a Mercury OptiMax outboard that won't start:
2001 Mercury OptiMax Won't Start
http://continuouswave.com/ubb/Forum3/HTML/013996.html
This article mentions a procedure for initiating an automatic priming of the fuel system.
grossjas posted 05-16-2010 08:12 PM ET (US)
You were exactly right, the battery was no good, it was strong enough to turn it over but not power everything else. I bought a new Optima Blue Top 31M battery, I hope it will be a good battery.
[Changed TOPIC to discuss boat batteries. Please use the SMALL BOAT ELECTRICAL discussion area to discuss boat batteries. Thank you.--jimh]

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Author	Topic: 1999 Mercury OptiMax Won't Start
grossjas	posted 05-15-2010 02:23 PM ET (US) I bought a used boat with a [1999] Mercury Optimax. [The Mercury OptiMax] started right up about a month ago. Now that it is boating season in northern Michigan, I went to start [the Mercury OptiMax] today, and it will not even fire. The [Mercury OptiMax] is new to me. I know nothing about it. Am I missing something? Help.
jimh	posted 05-15-2010 03:42 PM ET (US) It is unlikely that there has been much wear and tear on the engine from a month of sitting idle. On this assumption we turn to other causes for the failure to start, external to the engine itself. Most notable is the battery. The short version: If the battery is more than three years old, discard the current battery and replace it with a new battery with a MCA rating of 1,000-amperes or more. If the battery is less than two years old, recharge it. The long version: A Mercury OptiMax needs a very strong battery to start. Typically the battery must voltage must not sag during engine cranking. The OptiMax cannot be started without an external supply of electrical power to operate its electrical system. The electrical system of a Mercury OptiMax is a net consumer of electrical power until the engine speed reaches a fast idle. The Mercury OptiMax needs electrical power to run: --the engine control unit (ECU) computer electronics; --the electrical fuel injectors --the electrical air injectors Until the engine starts, all electrical power must be supplied by the storage battery used to crank it over. During engine cranking, if the battery voltage sags, it is very likely the ECU computer will not operate properly. The engine may very likely be impossible to start without a strong battery. The Mercury OptiMax is very well known for its demanding starting battery specifications. The minimum MCA rating for the battery is 1,000-amperes. To eliminate the battery as a possible cause of the no-start, I recommend you follow this procedure: --check the battery electrolyte level; refill to proper level if low --fully charge the battery with a proper charger; allow the battery to reach 100-percent charge and float there for a day to insure complete charging of the battery and restoration of cell chemistry; after letting the battery equilize its charge for several hours, measure the terminal voltage with a voltmeter with 5-percent accuracy. You should see at least 12.8-volts. --check all electrical connections between the battery and the Mercury OptiMax; by this I mean you should remove all connections, clean all terminals, remove any corrosion, restore all connections, tighten all retaining nuts or fasteners. Then, try restarting the Mercury OptiMax. Since it ran a month ago, it should run now. If this electrical service does not restore starting, investigate the fuel system. We can offer more advice on that once you check the electrical system.
jimh	posted 05-15-2010 06:10 PM ET (US) Using a search of the archives of CONTINUOUSWAVE with the search arguments "OptiMax" "No" and "Start", I found http://continuouswave.com/ubb/Forum3/HTML/015027.html --an article describing how replacement of the starting battery returned the engine to normal starting; http://continuouswave.com/ubb/Forum3/HTML/013626.html --an article describing starting problems and a recommendation to check the battery.
RevengeFamily	posted 05-16-2010 06:30 AM ET (US) Jim is 100% correct. I have twin 1999 Mercury 225 Optimax on my 1999 285 Conquest. With other engines you may be able to "squeek by" with a dieing battery, but not with the Optimax. I experienced something similar once before. I left my slip and motored 30 yards to the fuel dock. Shut the engines down and fueled up. (fueling took 20 minutes) To restart the engines I had to squeeze the primer bulbs again. Thought it was a bit strange considering I did not tilt the engines and they had been warmed up at the slip. Not sure what happened, but Optimax are definately a strange breed.
jimh	posted 05-16-2010 10:49 AM ET (US) Here is another good discussion from the archives on solving the problem of a Mercury OptiMax outboard that won't start: 2001 Mercury OptiMax Won't Start http://continuouswave.com/ubb/Forum3/HTML/013996.html This article mentions a procedure for initiating an automatic priming of the fuel system.
grossjas	posted 05-16-2010 08:12 PM ET (US) You were exactly right, the battery was no good, it was strong enough to turn it over but not power everything else. I bought a new Optima Blue Top 31M battery, I hope it will be a good battery. [Changed TOPIC to discuss boat batteries. Please use the SMALL BOAT ELECTRICAL discussion area to discuss boat batteries. Thank you.--jimh]