Source for Owner’s Manual, Wiring Diagrams for 1995 OFFSHORE 27 and Mercury 225-HP Engines

[Bawausa]

I just bought a 1995 OFFSHORE 27 with Mercury 225-HP twin engines. I have no manuals or wiring diagrams.

Q1: where can an owner’s manual be obtained for a 1995 OFFSHORE 27?

Q2: where can an owner’s manual be obtained for a Mercury 225-HP [later clarified to be possibly 2002 model year OptiMax] engines?

Q3: where can wiring diagrams be obtained for a 1995 OFFSHORE 27?

Q4: where can wiring diagrams be obtained for a Mercury 225-HP [later clarified to be possibly 2002 model year OptiMax] engine?

[jimh]

For help with engine manuals read at

https://continuouswave.com/whaler/refer ... nuals.html

You should mention the model and model year of the Mercury engines so that readers will be better able to help you located the particular owner's manual and the wiring diagrams for the engines you have. [Several replies later the engines were determined to be Mercury OptiMax engines]

[jimh]

For help with Boston Whaler boat owner’s manuals, contact Boston Whaler customer service.

You can also find many owner's manual and diagrams for Boston Whaler boats at this resource:

https://www.bostonwhaler.com/resources- ... nance.html

The does not appear to be any information for the OFFSHORE 27 model there.

The resource linked above does have extensive coverage of models in more recent years.

[Bawausa]

JIMH--thanks for your reply.

Q5: JIMH--do you know anyone that owns an OFFSHORE 27 offshore?

I might be able to get information from [an owner of an OFFSHORE 27]. Thanks

[Moderator's note: a duplicate of this article has been deleted. A third article asking for help in using the forum has been moved to the INTRODUCTION TO THE FORUM SOFTWARE forum.]

[jimh]

Q5: JIMH--do you know of any one that owns a OFFSHORE 27 offshore?

No. You can be certain that if I knew someone who owned an OFFSHORE 27 boat, I would have already suggested to you to contact that person.

[jimh]

I do not think there is anything particularly unusual or rare in the Mercury 225-HP engines. You should contact a Mercury dealer and inquire if you can purchase printed copies of the owner's manual. If you want wiring diagrams for the engine, you will have to purchase a printed copy of the service manual. Whether or not Brunswick (the parent company of Mercury) still has those printed publications available is unknown to me, but I would anticipate that a Mercury dealer who has been in business at least since 1995 might possibly have those publications on some dusty shelf in their back room.

[jimh]

I do not think there is anything particularly unusual or exotic about the 1995 OFFSHORE 27 that would require being explained in detail in an owner's manual. For many years Boston Whaler only published rather generic owner's manuals that covered many models and lengths of boat.

In the REFERENCE section there are two generic Boston Whaler owner's manual that I have reproduced into HTML documents. You may find the information they contain to be useful for understanding your OFFSHORE 27 boat. See

Manual 18 to 25 foot
Table of Contents
https://continuouswave.com/whaler/refer ... nual18-25/

Regarding detailed electrical schematic diagrams of a 1995 OFFSHORE 27, I have no knowledge if Boston Whaler ever provided such documentation. Typically the electrical installations in Boston Whaler boats were not particularly unusual or complicated. Boston Whaler only began to provide detailed electrical schematic diagrams for their individual boat models in the more recent years. Also, for most boaters, the detailed electrical diagrams are probably not extremely useful, as many boaters are not familiar with electrical schematic diagrams, their conventions, the symbols used, and other elements of the drawings.

Boston Whaler constructs the electrical wiring using a standard wire insulation color scheme in which the wire insulation colors is related to the function of the circuit. In the REFERENCE section the wire insulation color code scheme used by Boston Whaler is presented in detail in the article

Marine Wiring Color Codes
https://continuouswave.com/whaler/refer ... rCode.html

That same article also covers the wire insulation color coding used by Mercury in their outboard engines.

Anyone with familiarity with marine electrical power wiring, controls, and circuits should not have difficulty understanding the electrical circuits on a Boston Whaler boat. Boston Whaler boats tend to closely follow the American Boat and Yacht Council (ABYC) standards. There are excerpts from the ABYC standards for boat electrical system available on-line.

For more information on ABYC standards, see

https://abycinc.org/page/StandardsSupp58

See the section "E-11 AC & DC Electrical Systems on Boats"

You can purchase a PDF copy of the standard for $195. You can also find some excerpts from the standard on-line and available for no charge. For example, using a search I located this resource:

http://www.blackfinforums.com/sites/def ... c-e-11.pdf

[jimh]

If you are hoping for readers to assist you, I again remind you that you need to clearly describe the MODEL YEAR and the MODEL DESIGNATORS for the Mercury 225-HP engines for which you are looking for information or copies of the owner's manual and for electrical wiring diagrams. By giving readers this information, you will allow readers who have information on the particular model year and engine model of Mercury engine that you are asking about to assist you. Please provide that information so readers are not kept in the dark about what engines you need assistance in finding printed manuals or wiring diagrams.

[Bawausa]

The information I need about the boat is:

• gray water tank volume
• fresh water tank volume
• fuel tank volume

The wiring diagrams I need are:

• diagram on how to re-wire a Yamaha engine harness and ignition key switch to connect to a Mercury ignition key switch
• wiring of the four boat batteries to the engines
• wiring of battery charging outputs from the engines to the batteries
• wiring for the many pumps

BACK STORY

This 1995 27 Offshore was purchase by the Wilwaukee Police department in 1997. The boat came with two Yamaha engines, so all the controls say Yamaha. In 2002 the engines were changed to Mercury Optimax engines, designated as 225 DFI.

I never got the right [ignition key switch] keys from the Police dept. They keys they sent say L and R but do not fit.

I decided to change the ignition switches which are less than a $100 each.All the Mercury dealer and had was a 6-wire ignition switch. I ignition switches on the boat have 10 wires.

I want to find someone to build me a harness that would convert the ten wires to six wires.

The boat is missing the fuel gauge.

The boat has four batteries. Don't understand how the house batteries are getting charged.

I don't know how many bilge pumps are installed on the boat.

The boat was trailered from Milwaukee to Nevada and went through a bad rain storm. The boat has two inches of water in the cabin below. I have no clue how the water got there.

I am currently in India visiting my mom over the holidays and the boat is in Henderson, Nevada.

I plan to take off the deck [access] plates off, and then I will try to figure out all [the unknowns]. I got no help from Boston Whaler.

Thanks a ton for your help.

[jimh]

You have still not clearly stated the model year of the Mercury 225-HP OptiMax engines. Perhaps since they were installed in 2002 they might be model year 2002 engines. Usually the model year of an outboard engine is identified by a decal or tag or plate attached to the engine. You should make a close visual inspection of the engines and determine the model year.

[jimh]

The information I need about the boat is:

• gray water tank volume
• fresh water tank volume
• fuel tank volume

From the 1995 Boston Whaler catalogue:

The freshwater tank has a capacity of 30-gallons.

The fuel tank is aluminum and has a capacity of 243 gallons. However, there was an option for a larger tank with a capacity of 74-gallons more, for a total capacity of 317-gallons.

There is no gray water tank mentioned.

The standard equipment included a marine toilet and holding tank with macerator discharge pump. Use of a raw sewage discharge into the water will probably be illegal in any waters other than open ocean water and at a mandatory distance offshore and not in a designated no-discharge zone of the ocean. On that basis you should plan to disable to overboard discharge from the macerator pump, as just having that facility onboard could cause marine authorities to cite you for violation of non-discharge regulations that exist in almost every freshwater lake.

Regarding accumulation of rain water in the cockpit: as a general rule Boston Whaler boats will have through-hull drains that will allow any water accumulated in the cockpit and then drained into sump areas from the cockpit to then be drained overboard through the hull via a drain in the lowest portion of the sumps. These drains were probably plugged on the boat while it was in transit to you, and the battery switches were probably in the OFF position, resulting in the sump pumps not being able to operate. This configuration explains how water accumulated in the boat during transporting it across the USA.

There are two bilge pumps.

Regarding how Boston Whaler wires a sump pump, the normal configuration is for the pump to be controlled by a three-position switch. In the OFF position, no power is available to the pump. In the ON position, power is applied to the pump; and this position on the switch is normally a momentary position, that is, it must be manually held down or it will reset to OFF. In the AUTO position, power to the pump is controlled by a float switch or some other form of water sensor. The method of wiring of these switches often provides for the power used in the AUTO position to come directly from a battery, and not downstream of the primary ON-OFF switch for the battery. This allows for the pumps to operate while the battery switch is in the OFF position. If you are not familiar with wiring of DC control circuits, an article in the REFERENCE section describes the usual circuity. See

Cockpit Sump Pump
https://continuouswave.com/whaler/reference/bilgePump.html

[jimh]

The wiring diagrams I need are:

• diagram on how to re-wire a Yamaha engine harness and ignition key switch to connect to a Mercury ignition key switch

I doubt you can find a diagram from either Yamaha or Mercury that will give you a wiring configuration for using a Yamaha key switch and Yamaha engine harness to connect to a Mercury OptiMax engine. This unusual modification was probably created by the prior owners or operators of the boat, and is a one-of-a-kind installation. Lacking original documentation of what was done, there is no possibility of finding an accurate wiring diagram from another source.

A person familiar with both Yamaha and Mercury engine harness wiring and ignition key switch wiring MAY, after a careful inspection and documentation of what was done, be able to develop a new wiring plan for replacing the Yamaha ignition key switch wiring with a Mercury ignition key switch.

An alternative solution would be to purchase new Mercury engine wiring harnesses to connect to the new ignition key switches, and assume--a very big assumption--that something very weird has not been done inside the OptiMax engines or to their electrical connections that interface to the standard wiring harness.

A MUCH SIMPLER ALTERNATIVE would be to get a new key made to fit the existing ignition switches. A Yamaha dealer should have a variety of ignition key switches in stock, and I would expect that there would not be a thousand different keys. There may only be a ten different key in use. Also, a very close visual inspection of the ignition key switch may reveal an identify mark that encodes which key switch is to be used. This approach will be MUCH SIMPLER and MUCH FASTER and MUCH CHEAPER than your plan to tear out the Yamaha switches and replace with something completely different for the only reason you don't have a key that fits the ignition key switch. You should choose this plan and abandon your initial approach to solving this problem.

The wiring diagrams I need are:

• wiring of the four boat batteries to the engines

The wiring of the four batteries to the engine should be rather simple to discover. A close inspection of the batteries, the battery switches, and the engine primary power cables will provide enough information for a wiring diagram to be created by anyone who is familiar with boat 12-Volt high-current wiring, battery switches, and outboard engines. If you are not skilled in this area, you may be able to hire some one who has the requisite knowledge.

The wiring diagrams I need are:

• wiring of battery charging outputs from the engines to the batteries

The configuration for how each of the four boat batteries is to be recharged from the propulsion engines can be assessed in a similar manner as described above. I do not think that a Mercury OptiMax engine of c.2002 vintage would have an auxiliary battery charging output. The only charging current provided from the engine would be via the main power cables to the battery that was connected to those cables via the battery switch position.

The wiring diagrams I need are:

• wiring for the many pumps

The wiring of the many pumps is likely to be as I described in my prior reply regarding sump pump operation. Typically any switch which controls a pump will be identified by a nearby label its function. Wire color coding will also help deduce the circuitry.

[Bawausa]

Thank you Jim, the engines are 2002. When I get back I will keep you posted on what I find.

[jimh]

Regarding the existing wiring for the the primary power distribution using four batteries and twin engines, there is no way to know the exact circuitry that is in place. Much like the modification made to the boat after it left the Boston Whaler factory to employ Yamaha remote controls and engine ignition switches with Mercury OptiMax engines, there is no reasonable basis to assume that the present circuitry in the boat for handling the batteries for use with twin engines is exactly the same as when the boat was sold by Boston Whaler to the first owner.

The typical installation used by Boston Whaler for a twin engine boat was to have two batteries and two battery switches. In an article I wrote many years ago in the REFERENCE section on the topic of DUAL BATTERY WIRING, I show the typical circuitry used by Boston Whaler for a boat with twin engines and two batteries. You can find my article at

Dual Battery Wiring
https://continuouswave.com/whaler/refer ... ttery.html

The section that discusses Boston Whaler wiring for dual engines can be found under the subheading "Boston Whaler Factory Installation."

Again, there is no reasonable basis to think that the arrangement of FOUR batteries, two engines, and any number of battery switches after the boat has been out in the field for 29 years will be EXACTLY as it was when the boat was first delivered. On that basis, your quest to get "wiring diagrams" may not produce useful results. Boat electrical systems are very often changed from their original configuration as the boat is in use, and particularly when a boat has been modified in any way related to the electrical system.

For example, my own boat is a 1990 24-foot Boston Whaler, and its present battery and electrical power distribution system system is significantly different than it was when built in 1990. To now have a "factory" wiring diagram would be of no value and provide no useful information about the boat power distribution wiring as it now exists.