1985 Mercury 18hp Outboard trouble

HacksawJim

Recruit
Joined
Sep 22, 2010
Messages
5
ok guys...i just want to thank anyone and everyone in advance for even attempting to help a novice like me....

So the problem is, the thing just won't start. Here's a history.

Went to view the boat with motor a little over a year ago.

The thing wouldn't start. The old man took it to the local Repair shop, had the carb cleaned and plugs and coils replaced. The next day, it started up fine.

Bought the boat, took it out twice.

The first time, it was an idle only public fishing area, and the boat ran fine all day. Electric start worked everytime, it smoked a little, but it ran fine.

Second time, i get to open up the throttle. Going up river about a quarter mile, and it starts coughing. Buddy on the River pulls alongside, takes a look at some gunk in my bulb, rinses me off, and we get her to start one more time before she eventually dies again.

I take the carb off, take it up to the mechanic's shop, have it cleaned up real good. Meanwhile, i flush my tank and lines, renew with fresh fuel, replace a couple of dryrotted hoses, replace my plugs and wires.

Get the carb back, and the guy mentions adjusting something or another when i put the carb back on.

To be honest, i was in a hurry and i kinda was half listening, and i have no idea what he was saying...all i heard was "Cleaned up good, should be fine, adjust your doo wa dappy do and give me some money".

So the carb goes back on, with the rest of the makeover completed, and i just cant get her to start.

I DID check my fire, which led me to replacing the plugs and wires. With the new plugs and wires, she sparked once, didn't the next time, then sparked every time from there on after.

Any ideas guys?....please bare with me...this is my first outboard.
 

HacksawJim

Recruit
Joined
Sep 22, 2010
Messages
5
Re: 1985 Mercury 18hp Outboard trouble

OH..and for your troubles, if you're willing to help, i'll upload pictures, close ups, far aways, videos, ....

WHATEVER YOU NEED if it helps you help me...

thanks...
 

slyhatch

Seaman Apprentice
Joined
Sep 10, 2010
Messages
45
Re: 1985 Mercury 18hp Outboard trouble

hi buddy
I just went through my engine and it runs fine now.The adjustment he was prabably refering to is the idle screw located at the front right of the carburetor.Screw it in to a lightly seated position then back it out to a 11/4-11/2 turn .You may adjust it while the engine is running for a finale ajustment by listening to the motor run.
Sly
 

HacksawJim

Recruit
Joined
Sep 22, 2010
Messages
5
Re: 1985 Mercury 18hp Outboard trouble

hey thanks man...i hope it IS something that simple...i plan on going out and messing with it again in just a little while...I'll let you know how it went....thanks alot man...


anybody else?
 

HacksawJim

Recruit
Joined
Sep 22, 2010
Messages
5
Re: 1985 Mercury 18hp Outboard trouble

ok guys..

just went out and checked my carb adjustment screw....turns out it was out about 3 turns, so i reseated it and backed it out between 1/4 and 1/2 turn....

Still nothing..so i checked my spark again, and now i'm not getting a spark at either plug...

whats the deal?
 

trihull59

Seaman Apprentice
Joined
Jul 18, 2010
Messages
46
Re: 1985 Mercury 18hp Outboard trouble

check all your wires, im not to familiar with that engine upload some pictures of your elec system i.e. switchbox distributor ect
 

Really Old Guy

Petty Officer 3rd Class
Joined
Sep 1, 2009
Messages
84
Re: 1985 Mercury 18hp Outboard trouble

I have one of these, down in the shed. Good old motor.
Sounds like a fuel issue, for sure.
Are you getting it to the carb?
 

HacksawJim

Recruit
Joined
Sep 22, 2010
Messages
5
Re: 1985 Mercury 18hp Outboard trouble

yessir...getting it to the carb...getting it to the coils, or wherever it goes...the fuel lines on the inside of the motor are clear, and i can see the gas getting to where it goes...

the carb was just cleaned, and all fuel flushed/replaced....


I'll post pictures of the electrical system soon...this is one of the deals with the two coils on the top/back of the motor, two plugs beneath that, and a power pack sort of setup on the left hand side of the motor...

thanks alot guys....
 

starcraft1982

Petty Officer 1st Class
Joined
Feb 7, 2010
Messages
277
Re: 1985 Mercury 18hp Outboard trouble

FIRST,the screw needs to be 1 AND 1/4 out from lightly seated,not 1/4.As for spark,this is only the start of things to look at.Make sure battery is FULLY charged and motor is spinning enough rpms to produce spark.check all connections and clean them.Also a weak starter can also produce no spark by simply not turning motor fast enough.So,if compression checks good,then your next step will be getting spark to jump a 7/16" gap tester.Could be lots of things from bad wire to stator to?.Spend time reading and searching on here and how to troubleshoot electrical issues and buy or borrow the necessary tools(testers)for the job.MUCH cheaper than the replace and see method.Good luck
 
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