1990 DT15c - smoking and sparkplug condition?

[simplystressed]

I notice when my DT15 is idling or trolling, it seems to smoke quite a bit. I took the plugs out (new this year) and one seems significantly more fouled than the other. This is an oil injected motor, any idea what might be going on? Are there any filters I should be changing? Have no idea when they were last changed.

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

The carb on the one cylinder is just set a little rich, you can just adjust it a little more lean on the one that have the black plug .....

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

Thanks for the reply. Where can I adjust this setting?

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

the air/fuel mixture screw on the carb ... ideal setting is 1 & 1/2 full turns outwards from soft stop ....

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

Update - My engine only has 1 carb - how can I set the one cylinder a bit leaner so it doesn't fowl as bad?

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

just set the carb 1 & 1/2 turns outwards from soft stop ....

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

I've attached a pic - where is the A/F screw on the carb?

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

it is the one on the top of your carb as on the pic with the spring ....

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

it is the one on the top of your carb as on the pic with the spring ....

So just soft tighten it and turn it out 1.5 turns? More turns the richer or leaner it goes? Appreciate the help!

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

yes that is correct ....

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

I checked it on the weekend and it looks to be 1.5 turns out already. Should I tighten it or loosen it to lean it out a little.

side note: is this just for idle speeds or does that screw affect the entire rpm band A/F ratio?

 

[simplystressed]

Re: 1990 DT15c - smoking and sparkplug condition?

I checked it on the weekend and it looks to be 1.5 turns out already. Should I tighten it or loosen it to lean it out a little?

side note: is this just for idle speeds or does that screw affect the entire rpm band A/F ratio?

 

[robert graham]

Re: 1990 DT15c - smoking and sparkplug condition?

put a clean/new spark plug, then dump your gas and put some clean fresh gas in the tank with some Seafoam in it and run it a while and it should clean out. sounds like you may have some old, degraded fuel. Good luck!

 

[deejaycee_2000]

Re: 1990 DT15c - smoking and sparkplug condition?

inwards is more air and less fuel, outwards is more fuel and less air .... it wil affect the over all RPM, you can adjust it lightly outwards ...