CONTINUOUSWAVE

I have been boating since I was born--67-years-ago. I am new to Boston Whaler boats, but I have always liked them. I am not new to boating.

I am the new owner of a 1985 Montauk 17 as of October 2022. The MONTAUK 17 boat is in very good condition, but I have some concern about the engine.

The boat has a 1985 Johnson V4 90 engine, and the variable rate oiling mechanism has been removed.

A couple of years ago the previous owner said he winterized the engine by fogging it and running antifreeze through it, but didn't change the gear case oil. The previous owner said the boat has been kept in heated storage since 2012.

I drained and replaced the gear case lubricant. Upon opening the drain plug, about 25-ml of water trickled out, followed by some greasy goo that might have once been oil. When the boat was last put into storage I don’t know if the gear case lubricant was drained or not, but present appearance is concerning.

I refilled the gear case with new oil. The boat is now back in storage.

Q1: at this point, what other elements of the engine and boat should be checked?

In May 2023 I will pull out the boat from storage. That will be the next time I perform any work on the boat.

Q2: where can a factory service manual for a 1986 Johnson V4 engine with model designation J90TLCOS be purchased ?

I have found some for sale but the applicable model numbers do not include the "COS" suffix.

Q3: where can I find historical information about the OMC V4 engines?

Congrats on the boat.

unclecurt wrote:Q1: at this point, what other elements of the engine and boat should be checked?

In my opinion, you've done what you can for now, assuming you've serviced the rest of the engine and found it in good condition.

I recommend testing the boat in May 2023 using the following procedure:

• Fire up the engine on a hose to ensure starting, water pump operation, and basic idling.
• Take a test ride.
• Drain the gear case lubricant.
• Check for water intrusion.
• Completely service the gear case.
• Replace the water pump.
• Check seals.

My go-to for old OMC service manuals is Ken Cook company. You should be able to purchase the manuals you need here:

https://www.outboardbooks.com/manual/J90TLCO/Johnson/

Good luck.
--Bill

Welcome to the forum at continuousWave.

unclecurt wrote:Q2: where can a factory service manual for a 1986 Johnson V4 engine with model designation J90TLCOS be purchased?

My preference in service manuals is to have the original factory manual. Based on owning original factory manuals for several Evinrude engines, my impression is these manuals are extremely well written, have excellent illustrations, have large fold out diagrams of wiring schematics, and represent a very high level of technical documentation for the product covered. There is a small possibility that on some dusty shelf of a long-time dealer there is a new factory service manual waiting to be sold that is for your engine. Otherwise buying a used manual in good condition is an alternative. The service manuals often cover several years of production.

See more about the model designator of your engine below.

unclecurt wrote:Q3: where can I find historical information about the OMC V4 engines?

ContinuousWave collects historical information about Boston Whaler boats. For historical information about your MONTAUK 17 boat, read the article on that hull in the REFERENCE section of the website. Note that the forum is only a part of the information collected and organized here about Boston Whaler boats:

https://continuouswave.com/whaler/reference/16-17/

The continuousWave website does not try to collect and organize historical information about OMC outboard engines, so you generally won't find too much information about them here. There may be some data in the archives related to older OMC engines. To find this information use the SEARCH page at

https://continuouswave.com/whaler/search.html

I am sure there are other websites that focus specifically on older OMC engines. You should look there for resources that will give you the historical information about OMC engines that you are seeking.

MODEL DESIGNATOR
For help with the model designators of OMC engines, see this article in the REFERENCE section at

EVINRUDE-JOHNSON MODEL CODES
https://continuouswave.com/whaler/refer ... Codes.html

Decoding your engine's model designation of J90TLCO according that that reference yields
J = Johnson
90 = rated horsepower
T = tiller steering
L = 20-inch shaft length
C0 = production epoch 1985

The trailing "S" is unknown to me. The letter S is reserved as an indicator of a saltwater model. Usually that would precede the date code.


WATER IN GEAR CASE
Gear case oil is generally designed to take water into an emulsion with oil. When you opened the gear case drain port and you observed about 0.8-ounces of water (which is equivalent of 25-ml), that suggests that there was not much separated water in the gear case. The gray color of the oil is an indicator that there was water in emulsion with the oil, as the oil is designed.

If further examination of the gear case oil after operating the engine reveals more water intrusion, then you may need to replace the propeller shaft seal. Unless you are particularly skilled and familiar with replacement of propeller shaft seals on the gear case of an outboard engine, my recommendation would be to have an old-school OMC dealer who is familiar with this 37-year-old outboard engine perform any work associated with installation of new propeller shaft seals. On a 37-year-old engine there may be some corrosion of the fasteners that need to be removed in order to get to the propeller shaft seals, and those fasteners may represent an obstacle to the casual do-it-yourself engine repairer.

WHERE TO POST TO SEEK ADVICE ABOUT REPAIRS
To seek advice about repairs to the boat or engine, please start a new thread for each separate repair topic in the REPAIRS and MODIFICATIONS forum.