c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Electrical and electronic topics for small boats
joc1212
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c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby joc1212 » Wed Jun 29, 2022 1:12 pm

We have a 2016 Outrage 190 with Mercury 150 FOURSTROKE engine. We just got the boat; top speed on first trial was 41.6-MPH COG from GPS.

[Discussion of performance is not going to be the topic of this thread. This thread is moved to SMALL BOAT ELECTRICAL for discussion of the electrical problem.--Moderator]

Shortly after that test run an alarm "critical low voltage" occurred .I reduced engine speed to 3,000-RPM, and I headed for the dock.

At the dock the Mercury 150-HP FOURSTROKE stopped running. To re-start another battery and jumper cables were used. The second battery remained connected so the boat could be moved to its slip.

[At the slip the] engine speed was increased to high-idle speed. On a Smartcraft gauges the battery voltage was indicated as 11.2-Volts. From that I deduced there is a charging defect with the engine

Q1: could the low voltage have caused the Mercury 150-HP FOURSTROKE to have decreased performance?

Seems most 190 OUTRAGE boats with 150-HP are able to run at 50-MPH.

Q2: what is the cause of the engine not charging the battery?

The engine will be looked at by a dealer on July 3. 2022.

ASIDE: I love the 190 OUTRAGE and Mercury 150-HP FOURSTROKE engine combination.

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Phil T
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Location: Was Maine. Temporarily Kentucky

Re: c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby Phil T » Wed Jun 29, 2022 1:46 pm

Low voltage alarm on many models of Mercury engines can be caused by a failing battery OR loose battery connections.

Tighten the connections at the battery posts.

If the battery is more than 5 years old, replace it. Re-test.

I have a feeling it is one of the two items above and a trip to the dealer is unnecessary.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

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Phil T
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Joined: Thu Oct 22, 2015 6:08 pm
Location: Was Maine. Temporarily Kentucky

Re: c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby Phil T » Wed Jun 29, 2022 1:51 pm

For performance analysis, review the factory results.

Note the boats are tested in ideal conditions, light load and gear.

https://www.bostonwhaler.com/content/dam/boston-whaler/technical/resources/190-Outrage-Performance-2016.pdf

Subtract for:

Bottom paint
Current
Wind
Fuel load
Passenger load
Engine trim
Propeller installed versus original to the boat.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

dtmackey
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Re: c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby dtmackey » Wed Jun 29, 2022 3:42 pm

I've found that when batteries suddenly has low voltage like described, the cause sometimes can be a short within one of the cells causing the plates to short together.

Check the simple things first: power connections on the battery and on the engine.

D-

jimh
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Re: c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby jimh » Wed Jun 29, 2022 10:42 pm

Most engines, particularly the newer Mercury four-stroke-power-cycle engines with fuel injection CANNOT be started without a strong battery. This is why the user manual tends to recommend very large capacity batteries.

Based on about 45-years of experience in diagnosis of electrical problems related to equipment that needs a battery to operate, the first component to check is the battery.

As mentioned, a six-cell lead-acid battery produces a nominal full-charge voltage of about 14-Volts. If a cell is shorted and only five cells remain active, then the maximum terminal voltage during charging will be about 11.5-Volts.

Because you got a warning of "low voltage" after the engine was running at full-throttle, the alternator and regulator may have been damaged by trying to pump current into a battery with a shorted cell.

I am not familiar with the 150-HP FOURSTROKE, but typically Mercury uses a field-excited alternator driven by a belt and pulley off the engine crankshaft. For the alternator to work properly the battery has to have enough electrical energy to initiate the field current. So, again, a bad battery is going to cause problems.

Also, don't leave two batteries connected in parallel and expect the engine to charge them. Two batteries create too much load.

At this point you really do not know if the engine is generating the proper voltage and current from the alternator. The problem could be a shorted-cell battery.

Also, loose connections can very quickly damage an alternator.

A first step: buy a new marine AGM battery from a retailer. If you have the dealer sell you one you will probably pay a premium for it.

Leave your worry about ultimate top speed of the boat until you figure out the cause of the battery and no-start and "low voltage" alert.

Regarding the effect of a low voltage alert on engine power output: there could be an interaction. Modern fuel-injected engines need a lot of electrical power to run the injectors. Modern engines need a stable high-pressure fuel circulation system. A marginal battery could cause problems in the injector operation. A marginal battery could result in lower fuel pressure.

If fuel pressure is not at the nominal value, the amount of fuel provided to the combustion chamber will be abnormally less than expected. This will reduce power output. Again, modern Mercury FOURSTROKE fuel-injected engines with individual fuel injectors for each cylinder do not like to work properly without a very strong battery attached to the engine.

dtmackey
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Re: c.2016 Mercury 150 FOURSTROKE Battery Charging Problem

Postby dtmackey » Thu Jun 30, 2022 8:34 am

jimh wrote:Leave your worry about ultimate top speed of the boat until you figure out the cause of the battery and no-start and "low voltage" alert.
Jim is right: work on the problem at hand and then go back and figure out the discrepancy in top speed of your boat compared to similar boats. So many factors contribute to top speed differences that until you have a properly working engine and electrical system, top speed differences cannot be addressed.