1965 Kiekhaefer Mercury 35hp

Strychn9ne

Seaman Apprentice
Joined
Aug 27, 2016
Messages
34
Hey everyone, I just bought my first fiberglass boat the other day! She's a 1965 Starcraft Siren with a '65 Merc 35hp on her. I have not put her in yet, but did hear the engine run before I bought it. It's very seasoned looking with some dents, dings, and faded paint, but runs very well as well as going into gear perfectly. Compression is around 120 PSI on both cylinders (Was told the engine was around 140 PSI when it was new), and had the lower unit rebuilt and a used 3 blade prop installed before I bought it.

Anyways, I'm trying to gather some information on the engine before I take to the water. The previous owner told me he ran the boat on 91 octane (87 without ethanol is hard to find around here) at a 50:1 mix. I'm sure this has been covered many times, but I can't find any concrete answers on the correct mix ratio. To me 50:1 sounds pretty lean for an old engine like this. I also have a 1957 Evinrude Fleetwin 7.5hp that was on my old flat bottom, and that runs 24:1. Though I'm not sure if the Merc uses bushings throughout like the Evinrude does. I have not mixed anything for the Merc yet, but I bought some Quicksilver Premium 2 cycle oil for it but then couldn't find the mix ratio info. Does anybody know for sure what ratio to run? Are there any PDF manuals out there for this engine I could download? Any info is greatly appreciated. Feel free to share any history and fun facts too!
 

DeepCMark58A

Commander
Joined
Aug 17, 2015
Messages
2,030
Yes 50-1 is the correct mixture, the quicksilver 2 cycle should mix with 6 gallons of gas. I would find the serial number and figure out exactly what year and model of motor you have. You may have been told it was a 1965 but it does not hurt to double check.
 

Strychn9ne

Seaman Apprentice
Joined
Aug 27, 2016
Messages
34
Wow, kind of surprising there. I guess Mercury was ahead of the times in the 60's. I might try out 40:1 and see if it likes that, then I can use leftovers in my weed eater and leaf blower. That was always a pain with my Fleettwin, nothing else I own runs well on 24:1 haha!

Good idea, I'll definitely do that. The previous owner's grandpa told me it was a '65, so that's all I've got. Where is the number stamped on the engine block? I looked the cowling over closely but couldn't find anything there. Only had the cowling off for a short while before it started raining, but didn't find it. I'm planning on putting her in the water tomorrow for awhile for a shake down, so I'll look for it again before mixing up the fuel. What year did Mercury switch to 50:1 and real bearings instead of bushings? Also, do these engines usually have a charging system? It's electric start with electric choke, but also has a pull start.

Edit: Found a number on the tilt tube, below the chrome cowling cover. It's on a sticker that has operating instructions on it. It reads 1858819. According to Oldmerc.com, it is indeed a 1965.
 

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jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Good thing you verified the year. In 1966 there were major changes to the 35hp'
Some spec for your engine
30 cu in displacement
Bore 2 7/8"
Stroke 2.3"
Full throttle rpm range 4800 - 5300
Spark plug; AC M44C, Champion J6J
Plug Gap 0.025"
Point Gap 0.020
 

Strychn9ne

Seaman Apprentice
Joined
Aug 27, 2016
Messages
34
Yea it id definitely beneficial to know exactly what ya got that for sure! Great info there, thanks for that.

Anyways, tried to go out on the water today, only to find out my battery was dead! I left the key in the ignition switch and left it on all week! Of course, I didn't notice this until I had her in the water already and the truck parked 50 yards away. I attempted to pull start her, but ran out of motivation after a little while and went back home. Hopefully next weekend will be nice enough for a shake down cruise. Oh well, this will give me some time to re route some wiring, solder on some new connectors, and install my fish finder.
 
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