Hiring Marina To Evaluate Used Boat Before Purchase

[Boatthecape24]

I may buy a 2005 170 MONTAUK.

Q1: should I hire a marina to go through the boat and the engine at a cost of $500 to determine what needs to be done to the boat?

MORE ABOUT THE BOAT

The hull has bottom paint, but looks to be in good condition. The engine is the original Mercury 90-HP four-stroke-power-cycle engine using carburetors, and running time is unknown. The engine mounting place and pivot have rust. The mechanical steering is sticky. A new battery may be needed.

The boat electronics are older.

The condition of the cushions is average.

The galvanized trailer was made in 2010. The wheels have maintenance-free hubs,

I know the seller, who says the boat has not had much use since 2020; no use in 2021 and 2022, and just one use in 2023.

The asking price is $15,000.

I think the boat may need a new engine in 2027 to 2028.

I do not know if the Mercury 90-HP engine could provide a comprehensive diagnostic report and running time.

READERS: your thoughts will be much appreciated.

[jimh]

I may buy a 2005 170 MONTAUK.

Q1: should I hire a marina to go through the boat and the engine at a cost of $500 to determine what needs to be done to the boat?

As for hiring a "marina" to perform a survey, I would not hire a "marina."

Instead, I will give you some free advice. I think this will be a much better value proposition for you than spending $500 at "a marina."

The condition of the boat is generally easily assessed. It is an open boat, there is practically nothing hidden. The hull integrity is the most important aspect, and this can be assess just by a careful visual inspection, looking for any indication of damage to the gel coat surface such as crack, penetrations, soft spots. Observe the hull in the water at its static trim with the engine trimmed down, and the usual gear aboard. The boat should float so that the engine splash well drains are not submerged under water. There may be a slight lateral trim to the side on which the battery is installed; this is natural. There should not be a significant stern-down trim, but a slight general trim to down-by-the-stern is intentional to help drain water off the cockpit.

I do not know if the Mercury 90-HP engine could provide a comprehensive diagnostic report and running time.

The c.2005 Mercury engine will not have a diagnostic port.

For more background on the various models of the "Mercury 90-HP four stroke" engine, read my article that describes the several variant versions and their features:

A Brief History of the Mercury 90-HP FOURSTROKE
https://continuouswave.com/forum/viewtopic.php?t=2405

The "problem" with carburetors is also rehashed in the above linked article.

Because the engine has carburetors, I suspect that the engine you are considering is most likely to be the Yamaha-made engine. The power head was made by Yamaha in Japan. The power head was sold to Mercury, who adapted it to their electrical harnesses and connectors, then mated it to a midsection and gear case made by Mercury, painted everything black, and put the Mercury brand on it. Mercury was unable to manufacture any 90-HP four-stroke-power-cycle engines of there own until about 2006, when they adapted the basic 1.7-liter four-cylinder in-line block of their VERADO series of supercharged engines to become a 90-HP model with natural aspirated air intake.

You can identify the version of the 90-HP FOURSTROKE from the cowling shape. Read more in my linked article above.

The best immediate assessment of the engine will be to check the engine oil sump lubricant for color and contamination; check the gear case lubricant for indication of ingress of water; make a very careful visual inspection of the engine block, wiring harness, rubber hoses, spark plugs, and other components, looking for signs of any leaks, rusts, damage, and so on.

If the gasoline fuel is four years old, discard the fuel--probably only six gallons at most--and get fresh, non-ethanol gasoline. Put the boat battery on a good battery charger for a day, bringing it up to full-charge. Using a hose attachment, attempt to start the engine--following the exact pre-start procedure given in the engine manual. The engine should start and idle smoothly.

If a sea trial can be arranged, attend the sea trial and evaluate the boat and engine on the water. If the engine was properly prepared for storage and is in proper running condition, there is no reason why it would not continue to function for many years.

In general, this boat is almost 20-years-old, so it may need some restoration. You are in the best position of anyone to determine if the boat has received good care and proper maintenance, as you know the seller. Also, you know best about your own abilities or willingness to have the time and skill necessary to restore the boat.

But for me the most attractive aspect is the very modest asking price. If you do not buy this boat I am sure someone else will without hesitation.

Read this discussion from 2021 regarding a c. 2005 Mercury 90-HP four-stroke-power-cycle engine with carburetors:

Mercury 90 FOURSTROKE Carburetor Engine
https://continuouswave.com/forum/viewtopic.php?t=6171

A wide range of opinions will be expressed. Pay attention to the comments from participant SOSMERC, who is an actual Mercury mechanic.

[jimh]

The engine mounting place and pivot have rust. The mechanical steering is sticky.

If the boat has been used in saltwater, particularly warm saltwater, some rust is probably inevitable. The comment that the steering is "sticky" does raise a HUGE concern. If the engine pivot tube has not been properly greased and has internal rust, the repair could be labor intensive and expensive.

As a way to assess, disconnect the drag link from the mechanical steering actuator to the engine tiller. Rotate the engine by hand, observing if the movement of the engine is easy and free from obstructions.

At the same time, with the drag link still disconnected, rotate the steering wheel at the helm and observe if the "sticky" action remains or has been cured.

These simple tests will give you much insight into the condition of the engine pivot tube, and on the tilt tube.

If the engine cannot be easily rotated by hand after disconnecting the drag link, the problem is in the engine pivot tube.

If the engine is easily rotated by hand after disconnecting the drag link, but the steering is still "sticky", the problem is likely in the engine tilt tube, where the steering actuator arm is rusted or frozen in position. This is a much simpler repair, and much less expensive.

[jimh]

Also, because of the amazingly low asking price, you should not tell anyone else about this boat before you decide on buying or passing on it. If you tell anyone, they will probably go buy it before you decide.

[Boatthecape24]

Thanks Jim, this has been very helpful. At the price I can get the boat for, it seems that even if I have to repower sometime down the road there would be a good chance that I would get back most of my investment if I were to sell.

[Boatthecape24]

JIMH—thanks again. I spoke to the seller,and we are going to go forward. He knows a retired marine mechanic that he is going to ask to take a look at the steering and do a compression test on the motor. Deal of course is contingent on a sea trial. The existing 6.5 gallon fuel tanks are pretty old and probably be replaced. I may install a 22 gallon Moeller fuel tank instead.

[jimh]

A 90-HP four-stroke-power-cycle engine should be rather fuel efficient, so carrying 22-gallons will give the boat decent fuel endurance. To stay on plane will probably need 50-HP, which will be a fuel burn rate of about 4.5-GPH, or about 5-hours endurance, and at a speed of, say, 25-MPH, that will be a range of over 100-miles. I don’t know about you, but 5-hours and 100-miles in a 17-foot boat exceeds my endurance.

When you buy a “replacement” fuel tank for an older boat you may be able to avoid the current non-vented fuel tanks that can be problematic. Read my article on the MOELLER 22-gallon tank at

The MOELLER 24-gallon White On-deck Fuel Tank for Boston Whaler Boats
https://continuouswave.com/forum/viewto ... f=4&t=5807

More advice on buying Boston Whaler boats is given in

Buying Classic Boston Whaler Boats
https://continuouswave.com/whaler/reference/buying.html

Finally, purchasing a new engine for an older boat is not a financial “investment.” The moment a new engine leaves the dealership it loses significant value, and the value continues to decline as the engine hours and age increase. But a new engine is often an investment in more joy and fun in boating, often reducing worry about reliability, which is important on single engine boats. But at today’s prices a new engine will put a dent in your pocketbook.