1958 Mercury Mark 78

[GMC_DURAMAX_17]

Hello all, new to this forum so if this is posted in the wrong section please let me know. So to start off, I am an 18 year old guy living in south west Michigan. I recently got a 1950's Fleetform boat with motor and trailer, only needed trailer for my other boat, a 1978 sea sprite 16ft tri hull with a 75 HP Johnson stinger. I sold the 50's fiberglass hull to a buddy, who is making it a floating hunting blind. Now I am a Diesel tech so i dont know much about boat motors, but when i pulled the cover off the motor and seen an inline 6 cylinder engine i kept it, saving it from the scrap yard. Full details on the motor: 1978 Mercury Mark 78(A) (Super Marathon) (Dyna-Float) (Kiekhaefer) 2 blade prop. I believe it has electric start as well as the pull start. seems to be in good shape, original cover etc... Now for the bad: has sat on the tansom of that fleetform boat at least a decade. would need a full out restoration, not locked up does spin by hand. but it is all there besides the control box (boat was left hand drive, which most are right). My question is whats it worth? ive seen one or two for sale but both were missing pieces and beat to crap, one was $1200 other was $1000. Thanks for Reading!

 

[Jcris]

Hello young mariner,
Good to have you aboard. This is an exceptional forum as you know. Please post some pic's for us to follow along

 

[racerone]

That motor is what is called a " dock buster "------No gearshift.------Motor is stopped and started up running backwards for reverse.-----Needs the correct control box !

 

[Chinewalker]

Mark 78A would be a 1959. Solid motors, but they do have their quirks - as noted by racerone. The motor actually starts up backwards for reverse. Silent neutral (.ie motor stopped). Needs a good battery and charging system to work properly. If you plan on getting it running, get the OEM Pre-1965 service manual.

Value? Doubt you could get $1000-$1200 unless it was immaculate AND running. Their quirks scare most vintage boat folks away. Buyer would be either someone who won't be running it and wants something to complete a boat display, or someone who knows the motors and their quirks and is willing to deal with them. The former will want it to look good, and the latter likely won't pay that much as they want to do the work themselves.

 

[GMC_DURAMAX_17]

Thank you for the replies... I will get pics posted soon, and i now realize it is just a 78 and not a 78a. and the dockbuster nickname makes sense now lol. it had the control box in the boat, but it was completely seized up internally. still worth grabbing off boat? i can still get it. also would the hull have been worth anything? 1950's, fiberglass 16ft i think, it does float. just curious, i sold it to a buddy for $50 but he has not paid me yet so if its worth more ill go repo it haha. thanks again!

 

[Chinewalker]

Yes, get the controls. Seized is usually the cable - easy fix. If internal to the box, clean up and fresh grease usually fixes all.

Depends on the boat. Some of the really far-out looking 1950s finned classics can get some attention, but there were a lot of generic looking runabouts back then, too, that really don't have much of a following.