wiring harness 1974 85 hp outbard

[sandhopper2]

SN 4096602 85 hp mercury
I need to rewire the harness inside the motor , do the pins inside the plug come out ?
I have not run this motor yet so I don't want to spend the money for new harness , so if I can splice or replace the bad wires that is what I want to do
Also this motor seems to be stuck in gear can I turn something inside to get unstuck or do I have to drop the lower unit
I know I need to change the impeller but I would like to make sure it runs before I stick a bunch of money in her
Larry

 

[Chris1956]

Re: wiring harness 1974 85 hp outbard

I do not think the pins come out of the quick connect plug. A '74 motor should have a distributor. They would be simple to hotwire it, but for your purposes, you only need to know if it has spark and compression. Nothing else is important. So connect a battery with jumper cables to the frame (Ground) and touch the bolt on the starter (plugs out) and se if she spins. If so, test compression. If compression is 90+PSI and within 15%, the motor is good.

Post back and we can describe how to test spark.

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

Seems was stuck in Gear , forced the arm to what feels like N
Motor seams to be locking up , will turn flywheel by hand and will go only so far then stops
go in other direction again stops
Maybe a bad rod or piston skirt hanging up , or somethinkg in lower unit ?
What steps should I take next ? do I pull the head ?
Larry

 

[mercurymang]

Re: wiring harness 1974 85 hp outbard

Take the spark plugs out, then try to turn the motor again.

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

Plugs were out , could only turn part way around
I will try a socket on it in the morning , it feels like a ring , rod or piston is hitting on something
This motor may be too much trouble to repair
Larry

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

This motor will only turn over 1/2 way around in both directions then something hits , any ideas ?

 

[GA_Boater]

Re: wiring harness 1974 85 hp outbard

Are all the pistons moving? Almost sounds like you might have a broken rod.

 

[Chris1956]

Re: wiring harness 1974 85 hp outbard

Drop the gearcase, to eliminate that as an issue. If she still will not turn 360*, you have a real problem.

 

[Chris1956]

Re: wiring harness 1974 85 hp outbard

After dropping the gearcase, if you still have an issue, remove the two transfer covers on the starboard side of the powerhead and see if you can see the issue.

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

What are transfer covers ? any pictures ? What on the lower unit could cause it not to rotate 360 ?
Larry

 

[1960 Starflite]

Re: wiring harness 1974 85 hp outbard

With luck, the water pump impeller may be in pieces. Had a 30 HP Merc that way. Agree with others, drop lower unit.

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

now that make sence , I understand to drop the lower unit it takes 5 bolts and the gear slector nut
Sound like that is the first move in the morning , before the wife changes the work plan for the day

 

[Chris1956]

Re: wiring harness 1974 85 hp outbard

Well, 5 nuts and a bolt, to be accurate. You must remove the zinc anode to get at the hidden bolt. The upper and lower shift shafts will uncouple. The zinc anode can be removed with a thin wall socket (7/16" or 1/2") or an Allen Wrench, if the original bolt was replaced with a allen head bolt.

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

Ok I'm stumped
Lower unit do not free it up
Pulled the plates on the side and I can't see anything wrong Pistons move good got hold of the rods by a nut and they seem good
what do I try next ? the head plate ? Not sure if this is worth chasing but I just have to know now
Larry

 

[Chinewalker]

Re: wiring harness 1974 85 hp outbard

Take a look under the flywheel. I had one once that had sucked up a loose nut and it got caught between the magnets and stator. Would bind things up a bit...

 

[carholme]

Re: wiring harness 1974 85 hp outbard

You say that the pistons are all moving good. So presumably, the flywheel is now turning OK.

Gerry

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

No it still only does 180 and stops , I don't see anything under the flywheel or feel anything there to stop it
all the pistons move and rods seem to be ok the only thing I can think of is something in the top of the cylinder or crank case
It looks like the head is easy enough to remove so that maybe the next step
Larry

 

[GA_Boater]

Re: wiring harness 1974 85 hp outbard

You need a hacksaw to remove the head. The head is cast integral to the block. What you think is the head is the cylinder block cover, actually part of the cooling system. Item #26 here, Mercury Marine Model 850 85 HP(4 CYL.) END CAPS, MANIFOLD AND EXHAUST COVERS Parts

 

[Chris1956]

Re: wiring harness 1974 85 hp outbard

Gee, with the transfer covers off and the spark plugs out, you should be able to see everything in the cylinder, or pretty much so. Maybe the trouble in in the crankcase?

 

[sandhopper2]

Re: wiring harness 1974 85 hp outbard

so the plate on top is not part of the head , if I remove that I will not see the top of the piston ?
I guess I'm past what I can take apart with the motor on the boat
Need to build the stand and pull this thing
Larry