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80hp mercury outboard

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grimreaper

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"Hey guy, hope someone can hel

"Hey guy, hope someone can help me. I have a 1985 mercury outboard that will run smooth for 4 seconds then violently jerk, run smoth for another 4 seconds then jerk and on and on. this happens during idle and low trolling speeds. Slam down the throttle and she takes off up to 55mph without a miss. Cleaned and set up carbs, replaced plugs and rectifier. Any thoughts would be helpful. thanks"
 
"Make sure your fuel water sep

"Make sure your fuel water separator isn't clogged, and maybe check the fuel diagram to make sure its not got trash in it."
 
"You could be running on the l

"You could be running on the lean side sounds like lean cough to me. How many hours are on the motor?When have you lasted decarbed the motor ?
Trolling builds carbon. But you said it runs great at wot, So I would turn mix screw open on each carb 1/8- 1/4 to the rich side to see if that helps"
 
I have been through the merc m

I have been through the merc manual from cover to cover and cannot find any mention of a water separator. could it be known by another name? How does one decarb a motor? thanks for your help.
 
On an 85 you would not have a

On an 85 you would not have a water separator unless you installed one in the fuel line. Sea foam is what I use to decarbon my motors you can get at most any auto parts place or from here but your in Canada so check at your local boat shop.
Merc makes a fuel treatment and yami also any will work just ask the tech and tell him what you want to do..
I hope it helps let us know how you do

Hamit
 
hey can any1 help my 80hp blue

hey can any1 help my 80hp blueband and need 2 no where the 3 wires cuming out of the dizzy goes 2 as the black wire i think is a earth but when i bolt it up i dont get any spark but when i tap it on and off boat sumtimes runs real ruff and gotta keep touchin wire or it stops.boat shop said it cud be in the dizzy the part thats conected 2 the wires dont c how it can be when i have spark when tapping the wire on and off please help??!! my email is [email protected]
 
"The three wires from the dist

"The three wires from the distributor go to the switch box, black, brown and white.The three terminals on the switch box are normaly colour coded.The brown also hook into the mercury safety switch."
 
nope my wires are blue white a

nope my wires are blue white and black.the blue 1 goes to the switchbox as colour coded then runs to the mercury saftey
doesnt have a colour code on switch box for the black 1 thats y i think its a earth but when its earthed get no spark when turning it over but when i disconnect it and turn it over and keep tapping the black wire earthing it out i get spark
 
"finaly got constant spark whe

"finaly got constant spark when i connected the blackwire up this was not happening before.then i started it and it run mint as, stoped it a coule of times then left it for 5mins then tryed it again now im back to stage 1 again only geting spark when tapping the black earth wire cud it be the switch box at all???"
 
all wires are in the rite plac

all wires are in the rite place still no spark until i disconect earth and keep tapping the earth wire earthing it out. would ya think maybe my distributor is nacked maybe have a broken wire or something i have hunted for 1 for my model and cant find 1 anywhere its shaped like a horse shoe sort of thing its white and looks plastic
 
"Disconnect the mercury switch

"Disconnect the mercury switch and try .Post serial #
Test the coil with an ohmmeter, test that black wire for continuity,test them all,"
 
that vintage merc had horrible

that vintage merc had horrible wiring....check for anything with a green corrosive tint....around and where lugs attach to wiring..relug and recrimp as needed altho replacing wiring harness is better fix..check for wires being stiff...crystalizing(spelling) is what you are looking for..if a wire feels stiff then strip back insulation...you will find corrosion imbedded in strands..this can be either grey or green...this causes a voltage drop when current is being drawn..getting a wiring harness will be a problem i fear for that motor...but with a good soldering iron and patience you can rewire...
 
thanks 4 ya help carl checked

thanks 4 ya help carl checked 1 wire and it did hav sorta carbon stuff in it but wud dat drill all my spark totally ya think wires aint stiff tho i may hava go at rewireing it
 
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