1986 Mercury 9.8 110 outboard

[Kissdude]

It appears to be functioning, but once it warms up, it could become unstable.

If I have good spark on both cylinders a spray of premi9x into carb should fire correct? Cause I can't get this thing to fire at all

 

[jimmbo]

Air-Fuel, Compression, and Spark at the proper time and it should fire.
You have fuel, in the cylinder
What are the Compression Numbers?(this is a very long thread)
You have Spark at the Plug Wire
The chances of both Plugs being bad is unlikely
Maybe the Spark Timing is was off
Maybe there is Too much fuel in the cylinder. With the plugs out, the throttle wide open, and the choke off. Pull the Recoil several Times to clear out most of the Fuel.

 

[Kissdude]

compression numbers are around 98

 

[Kissdude]

Would anyone be able to tell me where I can find a diagram of the ignition system on my 110, 9.8 Mercury outboard serial no: 7151133, as I can't find a manual for it. When I research this outboard, I have noticed a some of them have two brown wires leaving the cdi box and head up to something above the fuel pump that my motor does not have and trying to figure out if I am missing a part.
Thanks in advance

 

[Mc Tool]

I have found a few manuals for a 9.8hp 110 mercury but not for 1986 year . I dunno for sure about your motor but often the same model is made for years and/or a manual may also be for different sized motors ...ie the 7.5 is pretty much the same motor. It may have a smaller bore or a shorter stroke ( this should be covered in a " one size fits all " manual )but is essentially the same . It may even be the same size but have a smaller carb or different porting to " detune " it .
Others with more knowledge on the subject may chime in and advise of a suitable manual . You may have to download a pdf file but ...I dunno about you but Im of an age (63 ) where Id rather have the actual book... but I have bought a few pdf manuals and they are ok . Keep a copy on a flash drive . One advantage is that you can expand the text if your eyes are not as young as they used to be
It might also transpire that a Tohatsu 9.8 is the same motor painted a different colour.....they did that . A possible way to see is to google the Tohatsu you tube vids and see if it looks the same as yours .
I have an 18hp Tohatsu and I know the same motor was sold as a Mercury and a Nissan .

 

[Scott Danforth]

oldmercs site or AOMCI.org

 

[Mohawkmtrs]

Rope Start or Electric Start?

 

[racerone]

Is the powerhead original?-----Only some pictures of it might explain the missing wires going to trigger?

 

[racerone]

With 6 drops of fuel in each sparkplug hole it should bark like a wild dog.----If not , you do not have strong spark or spark at the wrong time !----Simple as that.----With carburetor removed does opening in reed block line up?----Post picture of that.-----This motor should be simple to figure out.

 

[Scott Danforth]

Manuals

OldMercs.com is your one stop shop for all Mercury parts. We stock parts from 1940 to the present.

www.oldmercs.com

the service manual is $75

 

[Kissdude]

With 6 drops of fuel in each sparkplug hole it should bark like a wild dog.----If not , you do not have strong spark or spark at the wrong time !----Simple as that.----With carburetor removed does opening in reed block line up?----Post picture of that.-----This motor should be simple to figure out.

Ok. so I was able to get her to fire for like 2 seconds with premix in the spark plug hole. Now what?

 

[Kissdude]

I was able to get the reed block all lined up with the pin to block

 

[Nordin]

My experience of these Mercury is that the ignition coils goes bad.
They spark in atmosphere at plugs and with a spark tester.
But if you put them in a spark tester Mercotronic or similar (coil tester out of the power head) the insulation between the prime winding and the secondary winding in the coil fail.
The spark jumps inside the coil between the windings.

 

[Kissdude]

My experience of these Mercury is that the ignition coils goes bad.
They spark in atmosphere at plugs and with a spark tester.
But if you put them in a spark tester Mercotronic or similar (coil tester out of the power head) the insulation between the prime winding and the secondary winding in the coil fail.
The spark jumps inside the coil between the windings.

I have been using new coils I had on hand that I didn’t need for another motor so those are good. Does the choke need adjustment if it doesn’t close snug when pulled?

 

[Mc Tool]

I have been using new coils I had on hand that I didn’t need for another motor so those are good. Does the choke need adjustment if it doesn’t close snug when pulled?

Yes , sometimes you have to slacken off the screws holding the butterfly in the spindle ,close the choke and wriggle the butterfly so as to get in a position where the choke is fully closed and then nip the screws up again . Usually on a 2 stroke that butterfly must be fully closed or they can be hard to start from cold .
If the motor runs for a few seconds and splutters to a stop you may have to go to ½ choke coz they can easily over choke and flood ......they are not like 4 strokes