Need HELP! trouble with a Merc 850 85 hp reverse and start

[metmat]

I just recently purchased a '75 tri-hull open bow sport boat with a two cycle mercury 850 outboard motor from the mid 70s as well. When it runs it runs great but getting it started has become a painstaking affair. I have been using a blast of starting fluid/ether which definitely helps but after reading through a bunch of these forums understand that band-aid fix will cause more trouble in the long run. I am going to try the spray bottle with the 50:1 fuel/oil mix in place of the starting fluid this weekend but I was curious what else could I have looked at or maybe do myself? Is there anything that can be done that will eliminate the need to spray to start?

I was also wondering if anyone had any suggestions that would explain the reverse ceasing to work. If I put the throttle into reverse the engine rockets into really high revs but doesn't budge. This has made trips to the marina on a busy day extremely nerve racking!

 

[Moody Blue]

Re: Need HELP! trouble with a Merc 850 85 hp reverse and start

These motors by nature are hard to start when cold. They need lots of fuel to kick them over. Squeeze the primer bulb till its hard. Activate the choke. On your motor, likely with the MerControl type controller, you need the push and HOLD the choke button down while cranking it over.

Check is to make sure the choke is operating properly and the choke plates in the carbs close completely when activated.

Starting fluid = bad
Premix in spray bottle = good

As for the reverse issue, it could be a number of things.
1) shift cable may be misadjusted
2) shift shaft may have been misaligned during lower unit reassembly
3) lower unit clutchdog may be damaged

 

[metmat]

Re: Need HELP! trouble with a Merc 850 85 hp reverse and start

Thanks for the input Moody Blue.
I think I have found someone trustworthy to look at the reverse issue and I have found it always helps to go in with suggestions so they don't think they can take advantage of you. I am looking forward to using premix instead of starting fluid as well and I am glad I caught that before major damage. I know it is an older engine and not problem free but it is reassuring to know the issues I have been facing are typical for this model and my instincts aren't too far off.

I will look at the choke plates as well.

I thought of another quick question last night... Is it typical for a boat/engine of this age and design to require frequent charging of the battery? After a couple days of camping/boating a jump pack is required to get her started. Brand new battery and it was charged less than a month ago. I don't use the radio ever or leave the key clicked over. Want to make sure there isn't a larger underlying issue here. Thanks in advance!

 

[Moody Blue]

Re: Need HELP! trouble with a Merc 850 85 hp reverse and start

If the battery is running down so quickly then your charging system may not be working. I think that motor puts out about 9 amps running wide open. That should be enough to keep it charged under normal conditions. Unless you are idling it a lot or have some other load switched on (lights, pumps etc) then the battery is not being charged.

With the motor running, measure the voltage on the battery terminals. Should see 13+ volts. If you only measure about 12 volts then something is not right.