1966 Sea Coaster w/ 1966 Merc 650

[Jerry E]

When I restored my boat, I added weight to the original specs by adding Mahogany hardwood to the deck and seat boxes. When I bought the boat it came with a 1966 Merc 650 that ran.

With the added weight, do you feel that this boat will be adequately powered? I will need to have someone else look at the engine and possibly fix it to be reliable.

I do not want to spend money on an engine that will not provide adequate performance, such as getting on plane rather easily.

Please help with your thoughts. My preference is to rebuild Merc 650 if it will power the boat adequately.

Thanks.

[thegammas]

Hmm, somewhat of a loaded question. How big is your boat (sea lancer/ Tomboy?). How many people will you typically have, will you be pulling skiers, etc. Anyway - I would think 65hp should be fine if shes a sea lancer or smaller - especially if you have the motor prop'd nicely. you've not likely added so much extra weight that the performance will be that noticably different. If the 65 runs, put her on and try it out. See if you like it.

I was considering stepping down from 100hp to something between 65 and 80hp for the fuel and weight considerations.

I'm a total Merc Guy, so I am biased. And if you are going to sell off the 65, and your willing to give it away, and your willing to ship it, let me know!!

[Jerry E]

I usually would have just myself and wife in the 17' Sea Coaster and occasionally would have another couple (4 adults total). Not too much waterskiing, tubing really just a fun recreational boat for cruising or fishing.

The engine needs seals for the lower unit plus tune up etc., maybe (impellers ?) A engine mechanic estimated about $600 to get it running. When he actually sees it well find out then what I will take to make it reliable.

How much is an engine like this worth and how much should I spend to make it reliable is the question vs. getting a different engine, maybe more h.p. if that will make the boat perform better.

Any thoughts?

Thanks.

p.s. good try about shipping the engine your way. My feeling is that this engine isn't worth much in its current condition.

[thegammas]

Well, when I got my Merc it was all original. It ran, but barely. it's a 100hp six with a dual ignition set up. If I recall the 65hps, it's a six with dual points as well. I want a very reliable engine. I did a lot of work to mine so that I could feel I could trust it. All the ignition components were wore and so I replaced the points, condensers, rotor cap, plug wires, coils, coil wires. With that it ran very nicely. I also replace/rebuilt the fuel system. I know from experience that those 40+ year old parts would start to fail with renewed regular use. Also, the original fuel s system materials do not hold up well to the alcohol in today's fuel. I removed, cleaned, and rebuilt the carbs (they were filthy), rebuilt the fuel pumps, and replaced all the fuel lines and the balance lines. I bought the impeller and kit, but upon inspection of what was in the lower, I was able to verify that the seller had indeed put a new one in.

I've got at least $450 in parts in it. Also, had to have the prop rehubbed - again, with renewed use, the original hub quickly failed - add $115. And I did all the work myself. If a mechanic did the work, add a fair amount for labor. If it needs new power head seal, that's still more in labor and parts.

Mine is a fresh water engine with very good compression on all six cylinders and very good cosmetically, so it was worth the effort/money to me. Besides, I enjoy working on vintage motors.

In all seriousness, if you do decide to go with a different engine and don't want to keep the 65hp, let me know - the shipping alone would likely make it cost prohibitive for me - but I'd like to consider it.

[Sassy Lass]

Hello;

For what it's worth. I'm the original owner of a 63 Sea Coaster. I bought it along with a 63 Merc 650 in September of 63. I still own the boat.

The 650 was great with me and my girlfriend. I was 220# then and she was 100#. But with another couple I had to run the 650 full power to have a nice plane. I don't like to run any engine wide open for extended periods. May of 64 I traded for a Merc 1000, 100 hp and have never looked back.

The 650 was propped correctly so that was not an issue. With the 1000 and 4 POB it will cruise real nice at 3000 RPM. Wide open, 5500 RPM, as per Merc Spec., she is really hauling. The wake is almost flat with only the prop turbulance and a slight water disturbance out to the boat sides. The prop is a 3 bladed bronze, 17" pitch.

Whenever it was that Merc made the last 150 hp, tall, 6 cyl. engines I had a chance to buy one, new in the box with all rigging for a real steal. I contacted Mercury and a friend who had been a field rep for Thompson about using it on my boat. They both told me pretty much the same thing. Weight was the main issue and the 150 was just a few pounds heavier then my 100 and that the boat would handle it easily without any problems. That primary factor in boat speed was the hull design not how much HP was applied. That the 150 would gain little if any speed because they thought the boat hull was doing the best it was designed for.

Another issue, I wanted to keep the boat as near original as possible.

Love that boat!!!!!! Thanks for reading, nicholas

[Jerry E]

Well, I,ve been using the 1966 Merc 650 for anout a season and a half. Noticed a new issue. It will run fine for awhile and then cut out for an instant then keeo running. This can happen and any RPM. Seems to be happening more often each time I take it out. Also, doesn't seem to have the same power as before. Any ideas?

[thegammas]

Greetings Jerry! I enjoyed re-reading this thread. And I still have my Sea Lancer and the 100HP on it. You’ll come to know that I am a long-winded “poster”, so forgive the long read….

Your dropping performance could be the result of a number of issues. I’d need a bit more info to put you in the right direction. I'll bang out a few questions here, and point you to an excellent support site for old mercs of your vintage;

The Site; www.fiberrglassics.com. Go to the Mercury Outpost forum. A very supportive group of very knowledgeable people and they (we) love to trouble shoot.

The questions: What if any work has been done to the motor since your 2008 posting; How many hours on it since then; Do you know if there was any work done before you got it? I’ll assume no work since you got it since she was a runner, light to moderate hours since then, and that (forgive me) you’ve only basic knowledge of vintage motors.

These are breaker-point twin ignition systems. As the points wear (and vintage points wear faster than 'modern') , the ignition settings start to get sloppy. As points wear increases, dwell increases, synchronization between the points wonders off mark, timing wanders off mark (in relation to break points), etc.. She’ll start to use more fuel, be harder to start, not idle as smooth, she’ll seem sluggish, and performance will drop off. The cut-out could just be another symptom of a worn ignition, an intermittent ignition short, the ignition safety (cut off) malfunctioning, etc.

I’d tune her up first. That may solve it all, including the cut-out. If a tune up doesn't solve the issues (or she's been tuned recently), we can look further.

Feel free to write me directly at www.peterstransky@verizon.net. And again, the fiberglassics site is awesome for support of these old Mercs

By the way, since the time of the original posts, I’ve had a lot more experience with my 1000. I had 7 people in my sea lancer, and that 100HP had no problem bringing her to plane, and as mentioned earlier, with 4 POB, she’ll cruise all day at 3000 RPM.

Let us know!