TOPIC: 1959 Dorsett w/ Mark 58a - My First Boat and Post

Hello,

My name is Adam and I live just north of Sacramento. I know nothing about boats but am eager to learn. I picked up my first boat on Sunday and am hoping I got a good deal. I know that I have a 1959 Dorsett and believe it to be an El Dorado from my research but am hoping someone can help me confirm? I found the 1959 brochure but it appears there are a couple other 15' models.

I believe the motor is a 1959 Mark 58a.

I took the boat out on Sunday afternoon. I had a hard time starting up the motor despite it firing right up for the owner during our test ride. Ultimately I ran down the battery but it pulled started fine. It would idle really low and after an hour or so on the water would die if idled too low or between shifting. I've called everywhere in Sacramento in an attempt to find someone that understands and can inspect and/or work on these engines - but even the folks I've been referred to tell me they are no longer confident working on this engine.

A couple of questions I am hoping someone can help me out with.
1. Any recommendations on a service in Northern California?
2. If I take it out again do I risk doing any damage to the motor before it's serviced? (I am mixing two stroke/gas correctly)
3. I have found a Mark 55 and Mark 75 on CL and am wondering if it's worth picking one of these up for parts or possibly a future upgrade to the 75? Not sure if it's compatible. Would it be worth having for $250 depending on the condition? Is that a good price?

Anyway, thanks so much in advance for any information or advice on this boat. This newbie can certainly use all I can get. Cheers.

Oh and the B&W picture is my mother in law. Oddly enough, she saw the boat on Monday and said "that was my first boat!" Small world but hopefully good karama.

Nice looking rig! But you definitely must replace the impeller, any more use of the motor risks losing the pump and frying your lovely classic Merc. Not a horrible job but does require a tool to be either made or bought to remove the water pump cover. More on that later.

In answer of question #3, if the motors are intact and powerhead not frozen-up, Yes, Yes, Yes! You will be well on your way to becoming a Mercoholic!!! The MK 75 and MK 55 are predecessors to the MK 58 and are becoming more desirable all the time. If the motors you're looking at are not crusty, "Salty Dogs" they are certainly worth picking up for a couple hundred bucks.

Heck, working on the MK58 and a couple of other old Mercs will be an excellent introduction to the world of Classic Outboard Repair. You've picked some of the most popular and best-built outboards ever made.

Some version of the 4-cylinder inline Merc was being built all the way up to the 90's. That's quite a production run!

BTW something else I'd do on the MK 58 as general maintenance is to replace the fuel pump diaphragm(s). These sit around and dry up, deteriorate and fail inconveniently.

And unless the carbs have been serviced, I'd also recommend installing the latest version of the plastic float inside the carb. Old floats are not made of alcohol-resistant fuel, and unless you can get the Good Stuff (non-alcohol unleaded), the floats will eventually deteriorate and cause fuel issues.

They are not terribly expensive and are fairly easy to replace; you only have to pull the float bowl filters and cover to get at the float chamber. And the carb packing (gasket) kits are cheap, too.

Last thing, to do right away, is check the lower unit oil. If it's full of water, count on a bit of repair work when you do the impeller. If it's just dark, drain out the bottom and refill thru the same drain hole with Hi-Vis marine-grade outboard gear oil (you can find it at Wally's or NAPA, amongst others). Fill 'till oil runs out the "vent" (upper) plug. You can also buy a handy mechanical pump which goes in the quart jug of oil, and has a threaded adapter for the gearcase drain plug threads. Makes it so much easier and less messy.

My first Merc ever (eons ago) was a $25 MK 58A, from an ad on the shop bulletin board. I cleaned up the points, blew the trash out of the water pump, and skied that motor all summer. Never even hooked up the electric start, it always started on a couple of pulls.

Congrats on the selection of such a great old boat & motor combination, do some basic maint on the motor and it'll give you many more years of service. They don't build 'em like that anymore!

Cheers.........ed

adamoutofplace,

WELCOME ABOARD & PURTY RIG.

Fwiw, the Mercury Workshop manuals are available on amazon.com & ebay.com FOR CHEAP on DVD.
(The last one that I noticed on amazon were 6.99 plus S&H.)

Truthfully, I don't know much about Mercurys (I'm "a FAN OF" the 1955-65 OMC outboards, as you need NOT be a mechanic or have a lot of tools to work on those.) but LOTS of FG folk like them.

yours, satx

Wow thanks so much Ed! I really appreciate the good information and this is exactly what I needed to know! I'll hold off on running it anymore (cancelled the trip this Sunday) until I can track down the right parts and get this thing a tune up. And Satx - yes I did order a Mercury 1965 & Prior manual on ebay ($25 for a hard copy...probably paid too much) and am hoping that this is the right manual to help me out.

I don't think the lower unit is the original as there is some green paint showing under the 'cloud white' - going to look into it more this weekend and take a look at the other two Mark engines as well. Thanks guys.

Be warned, old mercs are very addicting. I started with the one that came with my boat and now have a dozen. Great old motors that are very dependable and relatively easy to work on. The green showing through the white isn't paint but rather a primer, All old mercs have it

dalesdeadbug wrote:

Be warned, old mercs are very addicting.

Hi,

My name is Ed and I'm a Mercoholic!!!

Welcome aboard. I was in your exact shoes three years ago. 1) New to me Dorsett from Sacramento 2) Sort-of running motor (mines a Scott) 3) Eager. This is all good. I didn't take the boat out the entire first summer because I had the boat at a mechanic who kept trying to sell me a new motor. Then I rolled up my sleeves and got 1) Another Scott motor for parts. 2) Every Scott manual I could find (many posted here). 3) Posted lots of questions here. I've worked on my boat and my wife says I have more fun working on it than riding around it in.

Everyone here is very helpful. My guess is the best mechanics in the US are here on this board. Most turn wrenches on their own motors and will give you any insight possible. There are even a couple members here who live near you so they may have local resources.

BTW - I saw that boat come up on CL and was tempted to go to Sac to get it. I'm glad you got it and will keep it going strong!

[in monotone] "Hi Ed."

Hi Ed - exactly. You guys called it, I'm becoming addicted. Picked up the other 58a yesterday morning and am looking forward to opening it up and am tempted to go back and pick up a clean looking 55. But I figure I should get one working before buying more. Thanks Shacomm and Dalesdeadbug! I'm learning more about these every day. One question, can I run this using muffs/puppy ears? I've read some people do and other say this doesn't work on vintage motors. Any advice?

Better to scrounge up a plastic water barrel, cut it to a suitable height, and stick the bottom end in the bucket of water. Then you'll be able to idle it in gear and get a decent adjustment on the carbs.

I like to have the water at least halfway up the center section, to make sure there's no question about the pump being flooded with water.

Some folks have adapted a flusher from an old JohnnyRude Big Twin to wrap around the water intake, but those are getting quite difficult to find, too.

Water barrel (and you can put a drain plug or valve down low on the side to drain it) works the best.

Very easy to slide the empty bucket under the transom-mounted motor, then fill with water. Or, back the boat up to the filled bucket and lower motor into it.

HTH............ed

p.s. congrats on your latest acquisition, you're well on your way!