New used Mercury 850 (1975)

I recently purchased this 1985 Hydra-sport for $1500. The motor will only start using starting fluid after which is runs very well. It only runs water out of the pee hole at a high idle and the water is like what comes out of the hot water faucet at home. At low idle there is no water at all coming out but steam comes out. We didn't run it but about 2-3 min. I just wanted to make sure the motor did run. I am replacing the impeller on the lower unit, gear lube. Question; What do you all recommend doing about the starting problem? This is my first boat and motor and I certainly don't want to be stranded. It has a #50 Minnkota powerdrive also w/ a eagle fish/depthfinder. They had the cranking and trolling battery's wired together so I separated them. New lights and wiring on the trailer now. Any thoughts will be appreciated.

Re: New used Mercury 850 (1975)

First quit the starter fuid or you won't have anything to fix, next buy a manual and remove the carbs and rebuild then, replace the water pump impeller and ck the gear lube and enjoy the boat and motor

Re: New used Mercury 850 (1975)

There is no lubricant in the standard type of "starting fluid".

Use 50:1 fuel mix in a squirt bottle instead; until you get the problem fixed.

Chuck

Re: New used Mercury 850 (1975)

Any idea what the problem could be? After it does start it runs really well. The squeeze bulb is hard and it does seem to be getting fuel. The plugs are clean. I have just ordered a manual for it. Maybe that will point me in the right direction.
Thanks for your inputs.
Eddy

Re: New used Mercury 850 (1975)

dont EVER use started fluid on a 2 stroke engine for starters. And the reason those batteries were wired together is your trolling motor is most likely 24 volt not 12 volt. So you might want to wire them back together if ya wanna use your trolling motor. As for the water you definately got a bad impeller. And your carbs could use a good cleaning. Get yourself some carb gaskets, some carb cleaner and a can of compressed air and clean the chit out of those carbs and you should run real good.

Re: New used Mercury 850 (1975)

Tadd_P said:

Get yourself some carb gaskets, some carb cleaner and a can of compressed air and clean the chit out of those carbs and you should run real good.

Click to expand...

I disagree. If you are going to the trouble of pulling them, might as well do it RIGHT and get a rebuild kit and rebuld them. Get a service manual. It is the best investment you can get to help you out. You will need it to do a link and sync on the carbs after you rebuild them.

Re: New used Mercury 850 (1975)

The trolling motor is a MinnKota Powerdrive PD50 which is 12v. The batteries were wired in parallel to give them more capacity, I think, but I don't think the cranking battery and the deep cycle should be together. I'll get another deep cycle to run parallel to other one and leave the starting battery to itself. What should a carb rebuild, link, and sync cost to have someone professional do it?

Re: New used Mercury 850 (1975)

Silly question, how are you choking the motor when you try and start? Are you holding the choke button down (or pushing in the key if someone installed later controls) and continuing to choke until the motor starts? These motors typically will require full choke until they fire.

With the key on, before you start the motor, do you hear a clicking when you engage the choke? If you don't, something's wrong. You might want to try choking it with the cowling off to make sure everything is moving as it should when you hit the choke.

Another Q, I'm assuming you've only run the motor on a flusher so far. It's entirely possible your starting issue could be a simple case of improperly-adjusted idle mixture needles. You can't tell much about idle mix when running out of the water, there's no load on the motor and no backpressure.

So, before tearing the carbs apart, you might want to turn the idle mixture needle in each carb fully clockwise until lightly seated, then back out approx 2 turns. That'll ensure the mixture is plenty rich to begin with. Final idle speed/mixture adjustments would be made in the water after the motor's fully warmed, idling in Fwd gear.

Once you get your impeller replaced and have checked the choke, see if it starts any better. If not, time to start looking for leaky vacuum hoses and perhaps tearing into the carbs.

HTH & G'luck........ed

Re: New used Mercury 850 (1975)

I do know the choke linkage is working when you push the key in. I ordered a manual yesterday. I'm not going to try starting it anymore at least until I have the impeller in. Don't want to take any chances on burning it up. NO MORE STARTING FLUID!! I'm not putting it out on the water until I know its right. Do not want to get stranded 5-10 miles out on the lake. Har de har har. Thanks for all your comments. I really enjoy being a part of this forum.

Eddy