switched plug lead problem...

[MystyBlue2]

Hi all im new to this site and relatively new to boating so my apologies if i sound as thick as 3 bricks from time to time.

I have a mariner (jap origin) 25hp 2stroke 2cylinder outboard 1980.

I have been trying to investigate a rough idle/misfire as my top cylinder was not firing after doing the lead test. Anyhow i put in new plugs cleaned the inside of plug leads with cotton buds give a spray with WD40 and top cylinder is back working again. I have 2 problems...FIRSTLY if i switch the plug leads to the oposite plugs it makes no differance at all to the motor running or starting and dont know if this is normal or an indication of a faulty coil pack or CDI unit as in a car its a big no no. SECONDLY it is very smokey and i know 2 strokes are smokey but i would expect it to smoke when cold then get less smoke when warm. However this it the complete opposite. Hardly any when cold start then lots of smoke the warmer the engine gets. Plugs have been in 8 weeks and fouled up already. My carb mixture screw is set to 1 and a half turns out from lightly seated and running 50-1 ratio with TCW3 outboard oil. Also very very low on power too dont know if any of issues above could effect performance but shes mounted on a 12ft seahog boat and struggles to plane. Average 10kn max!

Sorry for the blab just wanted to get as much info as i can,

Looking forward to your replies cheers in advance

Dan

 

[Plum]

Hi all im new to this site and relatively new to boating so my apologies if i sound as thick as 3 bricks from time to time.

I have a mariner (jap origin) 25hp 2stroke 2cylinder outboard 1980.

I have been trying to investigate a rough idle/misfire as my top cylinder was not firing after doing the lead test. Anyhow i put in new plugs cleaned the inside of plug leads with cotton buds give a spray with WD40 and top cylinder is back working again. I have 2 problems...FIRSTLY if i switch the plug leads to the oposite plugs it makes no differance at all to the motor running or starting and dont know if this is normal or an indication of a faulty coil pack or CDI unit as in a car its a big no no. SECONDLY it is very smokey and i know 2 strokes are smokey but i would expect it to smoke when cold then get less smoke when warm. However this it the complete opposite. Hardly any when cold start then lots of smoke the warmer the engine gets. Plugs have been in 8 weeks and fouled up already. My carb mixture screw is set to 1 and a half turns out from lightly seated and running 50-1 ratio with TCW3 outboard oil. Also very very low on power too dont know if any of issues above could effect performance but shes mounted on a 12ft seahog boat and struggles to plane. Average 10kn max!

Sorry for the blab just wanted to get as much info as i can,

Looking forward to your replies cheers in advance

Dan

Don't worry about switching the plug leads. It is not unusual, to simplify the ignition system, to fire both plugs every 180 degrees of crank revolution.

Www.solocoastalsailing.co.uk

 

[MystyBlue2]

Awesome thank you for clearing that up and replying

 

[gordmac]

How fresh is the fuel?
Well worth properly cleaning the carbs.

 

[MystyBlue2]

Fuel is 2 weeks old and carbs had a full strip and rebuild in feb of this year. Im thinking of changing from 50-1 fuel mix to 75-1 to see if its a slight over oiling issue. Ive read 100-1 is manufacture recommendations but a feel that that is pushing the limit on a 40year old outboard that may have taking a beating the last 39years. What do you guys think? 50-1.....75-1........100-1 and could over oiling cause my symptoms

Cheers folks

 

[gordmac]

Long shot but does it have autolube? Would imagine 50:1 would be ok.
If it has a choke per cylinder are they balanced?

 

[MystyBlue2]

No it is just a very basic 1980 technology with 2 cylinders and 1 carb, has not got any oil injection system at all. Under cowl seems very basic and nothing like what you see these days with sensors etc...i was advised that 50-1 was sort of generic for older 2 strokes pre 1990 but seems to be very low on power super smokey when warm and plug fowling every 8 weeks dont seem right. Sont want to cut out too much oil in fuel or could be catastrophic but i honestly dont know what the problem could be. Im totally stumped tbh

 

[MystyBlue2]

No it is just a very basic 1980 technology with 2 cylinders and 1 carb, has not got any oil injection system at all. Under cowl seems very basic and nothing like what you see these days with sensors etc...i was advised that 50-1 was sort of generic for older 2 strokes pre 1990 but seems to be very low on power super smokey when warm and plug fowling every 8 weeks dont seem right. Sont want to cut out too much oil in fuel or could be catastrophic but i honestly dont know what the problem could be. Also has only 1 choke for single carb. Im totally stumped tbh

 

[gordmac]

Have you checked the compressions?

 

[MystyBlue2]

No i have not checked compression yet. Do you think bad compression could be the culprit? If so il have to book in and get a test done

 

[MystyBlue2]

Also started to cough at higher rpms.

Seems fine at idle now and starts fine when hot and cold, this never ends

Video link below, looks like this is gunna be an expensive job, what do you think?