46 td20 5 hp, coughs alot now was great.

[pugerz]

I have an old td20 that i just switched out the plugs on and changed the gear oil. The old plugs were at least 20 years old and the gear oil looked original. Thought the motor would run like a champ but smoked more and coughed alot. seemed to have a miss. It ran and all but just not like it did before i switched out plugs. Ran a 16 to 1 mix, prior two gallons ran a 50 to 1 mix and found out to run a richer mix from this board. before there was alot of unburnt fuel coming out of exhaust but yesterday none, so that is good. Can someone help me with coughing and smoking of motor, Am i overlooking something here. There was no cough before i did the work ever with this motor.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

Check for good constant spark on both cylinders, if one cylinder isn't firing or is dead you will get a miss. Did you remove and clean the carb as well, it's a must for a motor that's been sitting for 20 years? PS- they do smoke and smoke a lot, these aren't like the outboards of today that run 50:1, they smoke like crazy. 16:1 is a little heavy, I run 24:1 in my 3hp Viking single and 24:1 is called for your motor too. Here is a vid I shot yesterday of the viking running, clean carb on mine and it smokes like this:

http://www.youtube.com/watch?v=YZBkPnYwMjo

 

[pugerz]

Re: 46 td20 5 hp, coughs alot now was great.

the motor has not been sitting for 20 years, I have run it alot last fall and have been out 4 times this year with it. This last time out, yesterday tho after replacing plugs and gear oil, it was coughing alot, ran decent, just appeared to be missing. Thinking of cleaning old plugs and sticking back in. The 16:1 mixture was given on this board bye a number of people with that motor. They said prior to 50s motors needed a higher mixture. Not sure now.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

What plugs number did you put in? Did you gap the plugs? I'll triple check the ratio.

 

[pugerz]

Re: 46 td20 5 hp, coughs alot now was great.

Not sure what plug number. I took the old napa plug to napa and they said that plug was last made 20 years ago. Marvelled at the age and gave me an autolite plug and said it was the replacement. Gapped at 30, gap i got off here and from them at store. Gap on old plug was greater maybe due to wear. Motor runs just coughs alot now. Tried to adjust knob on top for mixture but to no avail. Did make a difference somewhat.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

Here is another post on the issue:

http://forums.iboats.com/showthread.php?t=77855

http://www.outboardrepairs.com/topics/003773.html

http://hoodad.fortunecity.com/hd25troubleshoot.html

http://forums.iboats.com/showthread.php?t=123237

They all state 24:1 so I'm not sure where 16:1 came into play.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

Not sure what plug number. I took the old napa plug to napa and they said that plug was last made 20 years ago. Marvelled at the age and gave me an autolite plug and said it was the replacement. Gapped at 30, gap i got off here and from them at store. Gap on old plug was greater maybe due to wear. Motor runs just coughs alot now. Tried to adjust knob on top for mixture but to no avail. Did make a difference somewhat.

That motor calls for champion J8J which are long discontinued, they say the proper plug is a J6C for today's gas. Clean up the old ones and put them back in and see if it improves, may not like the autolite plug. Plugs do make a difference believe it or not. My Merc ran like crap, through in the proper champion plugs in favour of the A/C plugs that were in it and it ran like a champ.

 

[pugerz]

Re: 46 td20 5 hp, coughs alot now was great.

ok, i see that on all those posts. Looked back at threads for td20 and came up with some threads stating 16:1. I can dump fuel and put in another gallon of 24:1 and run it with that. Or run what i have out and see what she does. Do you think that is the problem with the coughing?

 

[pugerz]

Re: 46 td20 5 hp, coughs alot now was great.

Wow looked at your youtube video on your viking bktheking. My smoking is nothing like that. smoke puffs after the cough is all. What a little motor that seems to be indestructable to me. Just want to do right bye the old lady.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

16:1 maybe back in the day before TCW-3 oils, 24:1 is a safe bet with the tcw-3 oil. 16:1 won't hurt it, just make it smoke more. Try cleaning up the old plugs and see if it makes a difference before anything else.

 

[F_R]

Re: 46 td20 5 hp, coughs alot now was great.

Oil does more than just lubricate it. It also seals it. That is a third port motor and needs the sealing.

Nowhere do I see that you tried simply adjusting the carburetor. It will sneeze and pop big time if out of adjustment.

The wheel on top of the tank is the high speed adjustment. Running at full speed (on a boat in the water), turn it to the right till it starts to slow down, then back to the left enough to regain power. Then do the idle needle.

The bent rod on the front of the crankcase (where it spits out in your eye), is the idle needle. It is extremely sensitive. It should be about 5/8 turn open from lightly seated. Running at idle speed, turn it in till it sneeezes, then back out till it stops sneezing. Then recheck both.

Mix is 16:1, it is SUPPOSED to smoke a lot, and it is supposed to run on a boat in the lake. Running it in a barrel will smoke up the whole neighborhood and make adjusting the carburetor difficult if not impossible.

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

So why is everyone and their brother saying 24:1?

 

[steelespike]

Re: 46 td20 5 hp, coughs alot now was great.

Just stick with 16:1 You really can't tell the difference as far as the smoke and then you have a little lube cushion if you miss mix it.The motor won't suffer any damage running at 16:1 it could at 24:1.If you want to reduce polution us artificial 2 stroke
it is said to be biodegradable and smokes less.

 

[F_R]

Re: 46 td20 5 hp, coughs alot now was great.

So why is everyone and their brother saying 24:1?

Same reason I rarely answer oil mix questions: Everybody has their swear-and-be-durned opinion that cannot be shaken. I only answered this one because it involved coughing and snorting, rather than lubrication.

OK, accepting the challenge and realizing that even OMC publications don't always agree, I just now looked it up in the official 1976 Johnson oil mix chart. For that model they still said 16:1

EDIT: Typo---make that 1971

 

[bktheking]

Re: 46 td20 5 hp, coughs alot now was great.

I guess it's one of those opinion things. The only puzzler is why the ratio's have never been updated since the new and improved oils have been released, 16:1 was back when 30 weight oil was used.

 

[aganser]

Re: 46 td20 5 hp, coughs alot now was great.

Hi all.

I'm the owner of these 3 beauties:

http://www.youtube.com/watch?v=n99FZIqruXQ

And I'm in the camp that says run them at 16:1. While I agree oils have improved over the years these are sill old school motors. They don't use roller, ball or needle bearings nor do they have bearing seals. I guess some have had luck with 24:1, I just want to play it safe.

Some folks ran these on 50:1 and they run real good......for maybe a summer. Then when they don't idle and no amount of carburetor adjusting or rebuilding will help, these motors will be shot, as the bearing clearances get so great from accellerated wear the motor can't build crankcase compression enough to idle. So please be careful with any motor from that era.

They smoke a lot in a barrel, but on a boat they'll be just fine.

Have fun with your toys!!

Bob G

 

[F_R]

Re: 46 td20 5 hp, coughs alot now was great.

What I started to say, but didn't complete, is that the TD/TN Johnsons have a third port and rotary valve induction systems instead of the reed valves found on newer motors. Proper clearances on those parts are vital if you want a good running motor. The oil completes the sealing where the clearance leaves off.

 

[1946Zephyr]

Re: 46 td20 5 hp, coughs alot now was great.

A lot of these old motors will say 1/2 pint per gallon, for the mix. That would be 16:1 24:1 is just a tad under 6 oz of oil. For the longest time, I thought 8 oz was 24:1 and just recently found out it is 16:1. Oh well, my motors have been getting a little extra lube.

 

[pugerz]

Re: 46 td20 5 hp, coughs alot now was great.

Thanks for all your input on this motor. I ran motor again adjusting lower idle adjuster and upper idle adjuster this time, keeping the plugs i got from napa in the motor, still coughing alot runs ok but rougher and coughs. I never got any coughing with my 20+ year old napa plugs in it. I was not aware untill this post about the lower idle adjuster. Autolite a303 were the plugs they gave me. I cleaned up the old napa plugs that were in it and will try them next time out. This must be a plug issue?

 

[wbeaton]

Re: 46 td20 5 hp, coughs alot now was great.

First thing I would have done is to reinstall the old plugs and see if the problem persists. Sometimes new plugs just aren't any good. I'm not sure why everyone wants to replace plugs every year either. If it ain't broke...

Did you notice a difference when you turned the adjusting knobs or did it not make any noticeable change?