Mercury 85 HP 850 info needed

[fire831]

I'm looking at a boat that has a Mercury 850 85 HP motor. Ser# 4234701,Thunderbolt Ignition. Can anyone tell me about this motor? Year,and if they have had good or bad luck with them. Motor looks clean and as if it would be in good shape. Owner says it runs but we have not had a chance to get together and see if she'll start. I can get the motor, 16ft fiberglass boat and trailer all for $800.00. Looks like it might be a steal for me. Thanks for any info.

 

[Smig]

Re: Mercury 85 HP 850 info needed

That appears to be a 1975 which has a distributor ignition system. I recently purchased a 1976 850 with the electronic ignition. I can't tell you much about reliability since I am a newbie and have only had the 850 for 1 month, but I will tell you that it has been easy to work on so far! I will be curious to see what some of the veterans have to say...

Regarding the price, I think it really depends on what condition everything is in (Engine: compressions, lower unit, carbs/fuel pump, lower unit, impellor etc..., Boat: transom, floor, bilge, seats, covers. Trailer: hubs/bearings, tires, springs... ) Needless to say, prices can vary drastically...!!!

What finally dawned on me over this past year of learning about boating is that I can always find a better deal and a worse deal. What really matters is if it is worth it to me?!

 

[fire831]

Re: Mercury 85 HP 850 info needed

Thanks for the info.

 

[SeaKaye12]

Re: Mercury 85 HP 850 info needed

I have the same engine; although mine is a 1977 without the distributor.

When I first gotm mine; I asked similiar questions to what you're asking. Most of the response seemed to imply that it was an OK engine that might not win any awards, but was built well and was reliable.

So far I would concur with that...in so far as my experience has been very good so far. I'm into my second season now and haven't had any real issues, other than the normal maintenence stuff.

One exception to that was the condition of the internal wiring harness...something about the quality of the wires that Mercury was using back then leaves a lot to be desired...the insulation was just flaking off and even the wires themselves were corroded to the point where I had to pretty much redo all the wiring under the cowl. Pretty easy to do though.

Just remember that you're buying somethilng rather old....many people may have had their hands on it...I'd try to ascertain just what sorts of things have been done to it.....

Good luck...Chuck

 

[Texasmark]

Re: Mercury 85 HP 850 info needed

I had a mid '80's and all it did was run. Was an excellent starter, especially in cold weather when others at the dock were sitting on the trailer cranking and cranking and cranking.

The Merc distributor ignition was with them from the start, back in the '40's so, other than getting the timing right, it should be bullet proof on yours. Don't remember when they went to solid state.

Mark