Mercury/Mariner 6hp 2 stroke outboard

Kev UK · 06 September 2015, 17:11

Mercury Mariner 6 hp 2 stroke tiller control made in Belgium.
Started happening this year --- when pulling the starter rope FROM COLD the rope will kick back after about the 3rd pull .
The motor would normally start after 2 pulls.
The 4th pull feels like the engine is hard to pull over but it will then start.
Once started it will start and stop all day without any problems --- just the slightest of pulls gets it running .
The fuel is fresh and the 2 stroke oil is the same as I have used for years and new.
Plugs have been replaced with same result ...
Any help would be appreciated please.
Thanks Regards Kevin

Fenlander · 06 September 2015, 17:17

Well I'd be thinking timing. Does yours have a timing link rod to a fast idle knob and if so does this all look in place OK.

Kev UK · 06 September 2015, 17:55

Fenlander.
Many thanks for the reply --- the boat and engine are 25 miles away but may get to use here this week weather permitting.
I intend to take a strobe light with me to check for spark from the first pull of the rope.
I don't know about the linkage rod but there is a fast /slow idle knob on the front but I never touch this as she idles fine --- think this adjusts a slow running jet but there again it could be linked to a rod --- food for thought .
What I can't fathom out is once she is running she will start and stop all day until the next cold start a few days/weeks later.
I have a workshop manual so I need to take a closer look.
Thanks
Regards Kevin

Fenlander · 06 September 2015, 18:07

If yours has the same arrangement as my similar era 15hp there is a fast idle knob combined with choke/primer where pulling out squirts some fuel in from the primer... leaving it out is the choke on... and turning clockwise is the fast idle.

If it's the same as I'm thinking of and looks like this under the hood you'll see the fast idle knob operates a rod that raises the idle speed by moving the timing... just wondered if there was a problem there.

P1030582.jpg Photo by ljs399 | Photobucket

Kev UK · 06 September 2015, 19:16

Never seen anything looking like that under the hood !!!
Yes the knob is the choke and also fast/ slow idle but not a primer --- I've never used it as a primer --- just the bulb on the external fuel line.
I have the serial number somewhere ---
Thanks again.
Regards
PS The gear shift is on the left side of the engine not the tiller --- sorry if that has confused.

PPS .Just found the outboard pics --- no mine is older than yours with Mariner on the hood

Fenlander · 06 September 2015, 19:36

Ahh OK... is yours black or met dark grey?

Kev UK · 06 September 2015, 19:56

See my PPS edit on previous post --- Grey hood with Mariner on it --- older model than yours.
Regards

Kev UK · 07 September 2015, 19:45

Follow up ....
Engine hasn't been started for nearly 2 weeks --- I ran the carb dry after the last use.
Today .... connected a strobe and it flashed on 1st pull so there was something going on at the plugs so disconnected it.
Yes there is a stiff link wire that moves under the flywheel when the choke is pulled.
The choke knob has "slow" "fast" and "start" printed on it but I have never rotated this only pulled it out to choke.
Today I rotated it and depending where it is in rotation how much the stiff wire travels when pulled to choke.
In the "start" position -- fully clockwise --- and choked the motor would not start so I took the plugs out --- they were wet when shaken onto my hand.
I replaced both plugs but it took about 10 pulls before the motor spluttered into life ---- once it is started and stopped the slightest of pulls will get it running again.
I had to rotate the knob anti clockwise (choke off) to keep the motor idling
At no time did it kick back.
Used for about 2 hours of stop /start fishing with no problem .
The boat will be off the water soon and in my garden where I can look more into it , clean the carb ,filter ,etc and do some more head scratching.
Many thanks for your time.....
Regards Kev

Kev UK · 08 September 2015, 17:34

2nd update ....
Studied the workshop manual today and I never knew that when you pull the choke knob out it squirts fuel into the carb as mentioned ---- I thought it just closed off the air intake.
So yesterday I must have flooded the engine with my pulling the choke out several times trying to work out what was going on with the link rod --- makes sense now.
Thanks again for taking the time to reply.....
Regards Kevin

Nightfisher · 09 September 2015, 09:41

There touchy, I own one though tohatso-made merc. Easy to flood when priming just pull-out once after the cold start idle has been rotated clockwise.

Fenlander · 09 September 2015, 10:18

As nightfisher says easy to get it wrong when you can independently choose how many squirts of primer, idle level/ign advance and carb choke amount.

In the UK summer I've refined by experience to do as Nightfisher with idle speed fully up and one or two primer squirts but no choke. Usually that will be a first time start but if it hasn't started in three pulls then I give it choke.

If you do three full primer squirts as in the manual and have the fully choke out that risks it being so flooded by the time you've tried three or four pulls it takes loads more pulls with the choke off to clear... and by them an interested audience is usually gathering.

Early or late in the year when it's much cooler I go by the book using full choke.

Kev UK · 09 September 2015, 15:51

Thanks for the replies --- I have had the engine for 5 years (came with the boat) and just pull out the choke,give it 2 or 3 pulls and she is away then bang in the choke.
Because this summer has been so cool,the boat been idle for weeks on end as opposed to days and also no heat from the sun on the engine cowl to add some warmth my usual starting method seems not to work.
Now that I know what the choke knob actually does then I'll try different cold start methods --- the word "start" on the knob should have been a clue !!

I had an audience of 1 on Monday --- a guy sat on his Orkney waiting for the tide .
My engine eventually started and I went fishing ----- on returning Mr Orkney was still high and dry ---- I love these neap tides !!

Thanks again for your time and hints --- I have found out a lot about my motor since posting here . I await the next time I try to start it.

Kev UK · 25 September 2015, 20:31

Follow up --- hopefully sorted.
Used the motor today --- first time for weeks.
Found a photo taken in 2011 which just happened to show the motor and zooming in showed where the choke knob was set.
Rotated the knob anti clockwise so that the "pull to choke" writing was vertical ( couldn't read it without turning my head sideways !) as shown in the 2011 photo --- I've never messed with this knob but someone who changed the impeller for me earlier in the year must have.

No kick back and the motor started on the 2nd pull just like it used to ....

Many ,many thanks to all who took the trouble to read and post replies.
Regards Kevin