1964 Mercury 850 - Wont start without choke. Won't go into forward without stalling

Ok, I was going to write a long detailed story of my afternoon but then I figured it would be best to cut right to the chase.

Motor:
1964 Mercury 850 - Outboard

Problems:
- stalls out when put into forward drive unless I gun it hard, and even if i gun it hard, its hit or miss
- reverse seems to work better than forward (doesn't stall as much)
- will not start without being choked, even when warmed up
- does not put out serious power until control lever is pushed almost all of the way forward, then it is about an inch or two of movement between 1/4 power to full power
- once up to full throttle, it would randomly cut out on power like i was pulling back the throttle control lever, even though I didn't touch it (and i had my friend manually hold the throttle cable at full throttle)

a little background:
I was obsessed with the idea of buying a boat and this one popped up on craigslist for super cheap so I jumped on it. The guy I bought it from said he had it in the water last year. He also said it just needed a battery but it turned out the starter was completely fried. The boat looks like its been either sunk, or out in the elements for 5 years. Moss growing everywhere, the bilge pump hose was completely clogged with muck (which i cleared and replaced the pump). So needless to say I can't rely on his word so the gas in the tank is probably not all that good to be pumping through the motor. I probably should have drained it and put good gas in there before trying to run it. Live and learn.

My plan for this week is to drain the tank and clean it out but I'm not sure how. I'll also pull the carbs and clean them.

Whats the best way to go about cleaning a gas tank? This tank is your standard plastic tank, not a metal tank.

Should I really avoid ethanol gas? I keep hearing that its bad for these old outboards. But I have no clue where to get ethanol-free gas.

Should I take it to the "merc guy"that the guy at the marina told me to, or should I just tackle this myself. Like I said, the engine will run, just not exactly the way I want it to. I have the original manual and a clymer manual and feel confident that I can tackle most of the maintenance and component cleaning/rebuilding?

Any opinions/ideas on what might be causing these issues?


Sorry, wasn't exactly to the chase. But thanks for taking the time!

Re: 1964 Mercury 850 - Wont start without choke. Won't go into forward without stalli

Is that the 6 cylinder?

Does it have the manual choke and a electric choke?

Re: 1964 Mercury 850 - Wont start without choke. Won't go into forward without stalli

The PO said "it was in the water last year" but he didin't say it was running! I would clean out the fuel tank (you could just siphon the gas out), check the compression to see how good the cylinders are (100psi+ all within 10 psi), check the throttle cable movement it might be misaligned, the synch between the distributor and carb pickups might be off (use the setup procedure in the manual). That motor uses two sets of points that have to be setup using a degree plate that a Merc dealer might still have and might do it for you, or rent it to you.
I use ethanol gas all the time and used it in a 1960 700 with no problems.
You will be in better shape if you test and inspect every wire, carb and ignition part.
Clymer manuals are not as detailed as Mercury's so maybe you should look on ebay for the '65 and earlier' one.

Re: 1964 Mercury 850 - Wont start without choke. Won't go into forward without stalli

Putting it in forward puts more of a load on the engine VS reverse due to the prop pitch,that's why it works better that way,would be the same with muffs on.After taking merc850's advice run some Seafoam and StarBrite gas/ethanol treatment every other tank or so.At the end of the year make sure if you have gas left to run the ethanol treatment through the engine as well as putting in the right amount in the tank.Try tackling the job yourself the journey is half the fun. Replace the fuel pump diaphragm as well.I would use the Merc mechanic as a last resort as the people on here can guide you through,as a matter of fact there is a post with a tutorial on linc N snyc under the heading of ---- 115hp 1976 carbs--- on this page

Re: 1964 Mercury 850 - Wont start without choke. Won't go into forward without stalli

An OEM MERCURY manual for that motor WILL be your best friend.
Bought then on Ebay from 10 to 50 bucks.
GOOD reading.
Not trying to be an A hole, but you will learn more from that manual, that you can imagine, espiacally(SP?) with that year motor. .02

Re: 1964 Mercury 850 - Wont start without choke. Won't go into forward without stalli

I know this thread is almost a year old, but I had no idea you guys had replied with this advice! Thanks!

The motor is running great. No stalling and starts when I want it to (once its warmed up). Had me out all last season and already out again 2 weeks ago. Ran like a champ. Just had to fiddle with the carbs and put fresh oil/gas in it. Only gripes are its a ***** to steer, and you can hear it coming a mile away